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Platinum

Metals

Review

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VOLUME 55 NUMBER 2 APRIL 2011

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•Platinum Metals Rev., 2011, 55, (2), 73•

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Platinum Metals Review, Johnson Matthey Plc, Orchard Road, Royston, SG8 5HE, UKE-mail: [email protected]

E-ISSN 1471–0676

Platinum Metals ReviewA quarterly journal of research on the platinum group metals

and of developments in their application in industryhttp: //www.platinummetalsreview.com/

APRIL 2011 VOL. 55 NO. 2

Contents

Microstructure Analysis of Selected Platinum Alloys 7744

By Paolo Battaini

The 2010 Nobel Prize in Chemistry: 8844

Palladium-Catalysed Cross-Coupling

By Thomas J. Colacot

Dalton Discussion 12: Catalytic C–H 9911

and C–X Bond Activation

A conference review by Ian J. S. Fairlamb

A Healthy Future: Platinum in Medical Applications 9988

By Alison Cowley and Brian Woodward

Fuel Cells Science and Technology 2010 110088

A conference review by Donald S. Cameron

11th International Platinum Symposium 111177

A conference review by Judith Kinnaird

The Discoverers of the Rhodium Isotopes 112244

By John W. Arblaster

“Asymmetric Catalysis on Industrial Scale”, 2nd Edition 113355

A book review by Stewart Brown

Publications in Brief 114400

Abstracts 114422

Patents 114466

Final Analysis: Flame Spray Pyrolysis: 114499

A Unique Facility for the Production of Nanopowders

By Bénédicte Thiébaut

By Paolo Battaini

8853 SpA, Via Pitagora 11, I-20016 Pero, Milano, Italy;

E-mmail: [email protected]

Metallographic analysis can be used to determine the

microstructure of platinum alloys in order to set up

working cycles and to perform failure analyses. A

range of platinum alloys used in jewellery and indus-

trial applications was studied, including several com-

monly used jewellery alloys. Electrochemical etching

was used to prepare samples for analysis using optical

metallography and additional data could be obtained

by scanning electron microscopy and energy disper-

sive spectroscopy. The crystallisation behaviour of

as-cast alloy samples and the changes in microstruc-

ture after work hardening and annealing are described

for the selected alloys.

IntroductionOptical metallography is a widely used investigation

technique in materials science. It can be used to

describe the microstructure of a metal alloy both

qualitatively and quantitatively. Here, the term

‘microstructure’ refers to the internal structure of the

alloy as a result of its composing atomic elements

and their three-dimensional arrangement over dis-

tances ranging from 1 micron to 1 millimetre.

Many alloy properties depend on the micro-

structure, including mechanical strength, hardness,

corrosion resistance and mechanical workability.

Metallography is therefore a fundamental tool to sup-

port research and failure analysis (1–3). This is true

for all industrial fields where alloys are used. A great

deal of literature is available on the typical methods

used in optical metallography (4–6).

A large amount of useful information is available in

the literature for precious metals in general (7–10).

However, there is less information specifically

focussed on platinum and its alloys.

The present work aims to give some examples of

platinum alloy microstructures, both in the as-cast

and work hardened and annealed conditions, and to

demonstrate the usefulness of optical metallography

in describing them. This paper is a revised and

updated account of work that was presented at the


•Platinum Metals Rev., 2011, 55, (2), 74–83•

Microstructure Analysis of SelectedPlatinum Alloys

doi:10.1595/147106711X554008 http://www.platinummetalsreview.com/

24th Santa Fe Symposium® on Jewelry Manufacturing

Technology in 2010 (11).

Materials and MethodsA wide variety of platinum alloys are used in jew-

ellery (12–18) and industrial applications (10, 19–21).

Different jewellery alloys are used in different markets

around the world, depending on the specific coun-

try’s standards for precious metal hallmarking. The

alloys whose microstructures are discussed here

are listed in Table I. These do not represent all the

alloys available on the market, but were chosen as a

representative sample of the type of results that can

be obtained using metallographic techniques. The

related Vickers microhardness of each alloy sample,

measured on the metallographic specimen with a

load of 200 gf (~2 N) in most cases, is given for each

microstructure.

If metallographic analysis is aimed at comparing

the microstructure of different alloys in their as-cast

condition, the initial samples must have the same

size and shape. Mould casting or investment casting

can produce different microstructures, with different

grain sizes and shapes, depending on parameters

such as mould shape, size and temperature, the

chemical composition of the mould, etc. Therefore,

whenever possible, the specimens for the present

study were prepared under conditions which were as

similar as possible, including the casting process.

The specimens were prepared by arc melting and

pressure casting under an argon atmosphere to the

shape shown in Figure 1. A Yasui & Co. Platinum

Investment was used, with a final flask preheating tem-

perature of 650ºC. The captions of the micrographs

specify whether the original specimen is of the type

described above.

The preparation of the metallographic specimens

consists of the following four steps: sectioning,

embedding the sample in resin, polishing the metallo-

graphic section, and sample etching for microstructure


doi:10.1595/147106711X554008 •Platinum Metals Rev., 2011, 55, (2)•

Table I

Selected Platinum Alloys

Composition, wt% Melting rangeaa, Vickers microhardnessbb,ºC HV220000

Pt 1769 65c

Pt-5Cud 1725–1745 130

Pt-5Cod 1750–1765 130

Pt-5Aud 1740–1770 127

Pt-5Ird 1780–1790 95

Pt-5Rud 1780–1795 125

70Pt-29.8Ire 1870–1910 330

70Pt-30Rh 1910f 127

90Pt-10Rh 1830–1850f 95

60Pt-25Ir-15Rh n/a 212

aSome melting ranges are not given as they have not yet been reported bThe microhardness value refers to the microstructure of samples measured in this

study and reported in the captions of the FigurescHV100dThese alloys are among the most common for jewellery applications. Where it is not

specified, it is assumed that the balance of the alloy is platinumeThis alloy composition is proprietary to 8853 SpA, ItalyfSolidus temperature

detection. The detailed description of these steps

will not be given here, as they have been discussed

in other works (4–10).

Further advice relevant to platinum alloys was given

in the 2010 Santa Fe Symposium paper (11) and in

this Journal (22). In these papers, procedures for the

metallographic analysis of most platinum alloys are

described. The samples for the present study were

prepared by electrolytic etching in a saturated solution

of sodium chloride in concentrated hydrochloric

acid (37%) using an AC power supply, as described

previously (22).

Microstructures of the Platinum AlloysIn this section the microstructures of the selected

platinum alloys in different metallurgical conditions

are presented. As already stated, this selection is a

representative sample and not a complete set of the

platinum alloys which are currently on the market.

As-Cast Microstructures: Metallographyof CrystallisationExamination of the as-cast microstructures shows

the variation in size and shape of the grains in differ-

ent platinum alloys. However, a noticeable dendritic

grain structure is quite common. The largest grain

size was found in platinum with 5 wt% copper

(Pt-5Cu) (Figure 2) and platinum with 5 wt% gold

(Pt-5Au) (Figure 3), with sizes up to 1 mm and 2 mm,

respectively. The Pt-5Au alloy sample also shows

shrinkage porosity between the dendrites. The core

of the dendritic grains showed a higher concentra-

tion of the element whose melting temperature was

the highest in both cases. This behaviour, known as

‘microsegregation’, has been widely described (12,

23, 24). Electrolytic etching tended to preferentially

dissolve the interdendritic copper- or gold-rich

regions, respectively. In a platinum with 5 wt% iridium

(Pt-5Ir) alloy (Figure 4), since iridium has the higher

melting temperature, the dendritic crystals were

enriched in iridium in the first solidification stage.

It is important to point out that the higher or lower

visibility of microsegregation within the dendrites is

not directly related to the chemical inhomogeneity,

but to the effectiveness of the electrolytic etching in



Diameter:25 mm

Cross-ssection diameter: 3 mm

Fig. 1. General shape of specimensprepared by investment casting for thisstudy. The microstructures of different alloysobtained by investment casting can becompared, provided that the specimens havethe same size and shape. The dashed lineshows the position of the metallographicsections examined in these samples

500 µm 500 µm

Fig. 2. As-cast Pt-5Cu alloy showingdendritic grains with coppermicrosegregation (sample shape asin Figure 1; flask temperature 650ºC;microhardness 130 ± 4 HV200 )

Fig. 3. As-cast Pt-5Au alloy showingshrinkage porosity between thedendrites (sample shape as inFigure 1; flask temperature 650ºC;microhardness 127 ± 9 HV200 )

500 µm

Fig. 4. As-cast Pt-5Ir alloy withcolumnar grains (sample shapeas in Figure 1; flask temperature650ºC; microhardness95 ± 2 HV200 )

revealing it. For example, the microsegregation in the

platinum with 5 wt% cobalt (Pt-5Co) alloy is hardly

visible in Figure 5, despite being easily measurable by

other techniques (24).

Scanning electron microscopy (SEM) and energy

dispersive spectroscopy (EDS) are very effective in

showing the presence of microsegregation. Figure 6shows an as-cast sample of a platinum with 25 wt%

iridium and 15 wt% rhodium alloy (60Pt-25Ir-15Rh).

The SEM backscattered electron image is shown in

Figure 7.The EDS maps in Figures 8–10 give the ele-

mental distribution on the etched surface. If the maps

were obtained on the polished surface the approxi-

mate concentration of each element may be different

due to the etching process and a possible preferen-

tial dissolution of different phases of the alloy.

However, because EDS is a semi-quantitative

method, it can only give the general distribution of

the elements on the metallographic section. It is

worthwhile remembering that metallographic prepa-

ration reveals only a few microstructural features. By

changing the preparation or the observation tech-

nique, some microstructural details may appear or

become more clearly defined, while others remain

invisible.

The melting range of the alloy and the flask pre-

heating temperature affect the size and shape of

grains significantly. In order to decrease the dendritic

size and obtain a more homogeneous microstructure,

the temperature of the material containing the solidi-

fying alloy is lowered as much as possible. The effec-

tiveness of such an operation is, however, limited by



500 µm

Fig. 5. As-cast Pt-5Co alloywith small gas porosity (sampleshape as in Figure 1; flasktemperature 650ºC; microhardness130 ± 6 HV200 )

200 µm

Fig. 6. 60Pt-25Ir-15Rh alloy castin a copper mould. From thetransverse section of an ingot(microhardness 212 ± 9 HV200 )

50 µµm

Fig. 7. 60Pt-25Ir-15Rh alloy:scanning electron microscopy(SEM) backscattered electronimage of the etched sample. Thesample is the same as that shownin Figure 6

50 µm

Fig. 9. 60Pt-25Ir-15Rh alloy:energy dispersive spectroscopy(EDS) iridium map acquired onthe surface seen in Figure 7. Theiridium concentration is lowerwhere that of platinum is higher

50 µm

Fig. 10. 60Pt-25Ir-15Rh alloy:energy dispersive spectroscopy(EDS) rhodium map acquired onthe surface seen in Figure 7. Therhodium distribution follows thebehaviour of iridium. The zones ofhigher iridium and rhodium contentshow this approximate composition(wt%): 55Pt-28Ir-17Rh

50 µm

Fig. 8. 60Pt-25Ir-15Rh alloy:energy dispersive spectroscopy(EDS) platinum map acquiredon the surface seen in Figure 7,showing the platinum microsegre-gation. The network of highplatinum content shows thisapproximate composition (wt%):72Pt-14Ir-14Rh

the melting range and by the chemical composition

of the alloy. An example of the flask temperature

effect is shown in Figure 11 for Pt-5Ir poured into a

flask with a final preheating temperature of 890ºC.

This microstructure is to be compared with that in

Figure 4, in which a flask preheating temperature of

650ºC was used.

A smaller grain size was observed in the platinum

with 5 wt% ruthenium (Pt-5Ru) alloy, which showed

a more equiaxed grain (Figure 12) with a grain size

of about 200 µm. The addition of ruthenium led to

finer grains in the platinum alloy.

Pouring the alloy in a copper mould produces

a smaller grain size due to the high cooling rate, as

visible in Figure 6 and Figures 13–15. In this case,

the high iridium and rhodium content also con-

tributed to the lower grain size in the as-cast sample.

Homogenising thermal treatments result in a

microstructural change. Comparing Figure 16 with

Figure 17 highlights a reduction in microsegregation

in Pt-5Cu as a consequence of a homogenisation

treatment performed at 1000ºC for 21 hours.

Work Hardened and AnnealedMicrostructures: Metallography ofDeformation and RecrystallisationOptical metallography can reveal the changes in

microstructure that occur after work hardening and

recrystallisation thermal treatments and allows

recrystallisation diagrams like the one in Figure 18 to



500 µm 500 µm

Fig. 11. As-cast Pt-5Ir alloy (sampleshape as in Figure 1; flasktemperature 890ºC; microhardness105 ± 2 HV200 )

Fig. 12. As-cast Pt-5Ru alloy showingshrinkage porosity at the centre ofthe section (sample shape as inFigure 1; flask temperature 650ºC;microhardness 125 ± 5 HV200 )

200 µm

Fig. 13. 70Pt-29.8Ir alloy: cast in acopper mould. From an ingot trans-verse section. A high iridium contentcontributes to grain refinement(microhardness 330 ± 4 HV200 )

200 µm

Fig. 14. 70Pt-30Rh alloy: cast in acopper mould. From the transversesection of an ingot. A high rhodiumcontent enhances the grainrefinement (microhardness127 ± 9 HV200 )

200 µm

Fig. 15. 90Pt-10Rh alloy: cast ina copper mould. From the trans-verse section of an ingot. The gasporosity is visible (microhardness95 ± 5 HV200 )

500 µm

Fig. 16. Higher-magnification imageof as-cast Pt-5Cu alloy showingdendritic grains with copper micro-segregation (microhardness 130 ± 4HV200 ). Compare with Figure 17

be drawn. This makes it a valuable aid in setting up

working cycles. It is necessary to establish the right

combination of plastic deformation and annealing

treatment in order to restore the material’s worka-

bility. This allows suitable final properties to be

achieved.

An example of the changes in microstructure after

various stages of work hardening and annealing is

shown in Figure 19 for the 60Pt-25Ir-15Rh alloy. This

can be compared to the as-cast structure shown in

Figure 6.

Drawn wires show a very different microstructure

along the drawing (longitudinal) direction in compar-

ison to the transverse direction (Figures 20–22 for

Pt-5Au). However, after annealing, the microstructure

becomes homogeneous and the fibres formed after to

the drawing procedure are replaced by a recrystallised

microstructure (Figures 23 and 24). Using the tech-

niques described elsewhere (11),analyses can be per-

formed even on very thin wires,as shown in Figure 25for a platinum 99.99% wire of 0.35 mm diameter.

It is worth pointing out that some binary platinum

alloys have a miscibility gap at low temperatures, as

shown by their phase diagrams (19, 20, 25). Examples

of this are given in Figures 26 and 27 for Pt-Ir and

Pt-Au, respectively. Similar behaviour is observed for

Pt-Co, Pt-Cu and Pt-Rh alloys.

As a consequence, a biphasic structure is expected

of each of them. However, this may not occur for var-

ious reasons. The phase diagrams refer to equilibrium

conditions, which hardly ever correspond to the

as-cast conditions. One of the two phases is some-

times present but in low volumetric fraction, due to

the chemical composition of the alloy, in which one

of the two elements has a low concentration.

Furthermore, the thermal treatments may have

homogenised the alloy. Finally, the metallographic

preparation may not be able to reveal such biphasic

structures. Therefore, it is necessary to use other

analytical techniques to detect the type and

concentration of the alloy phases. Only in specific

cases can the biphasic structure be revealed.



Annea

ling

tempe

ratu

re, ºC

Size

of

grai

n, m

m

Deformation, ε %0 10 20 40 60 80

1700

1500

1300

1100

900

700

1.6

1.1

0.6

0.1

Fig. 18. Recrystallisationdiagram of a platinum-rhodium alloy annealedat a set temperature fora given time after adeformation of ε %.Adapted from (10). Byincreasing the annealingtemperature the grain sizeincreases. During annealingthe grain size also increasesif the previous deformationis reduced

500 µm

Fig. 17.Microstructureof Pt-5Cu alloyafter thermaltreatment at1000ºC for 21hours. Themicro-segregation ofcopper isreduced (micro-hardness 120 ±4 HV200 ).Compare withFigure 16

The best results in working platinum alloys are gen-

erally achieved by hot forging the ingot during the

first stages of the procedure. Metallography shows the

differences between a material that has been cold

worked and annealed (Figures 28 and 29 for Pt-5Cu)

and a material that has been hot forged (Figures 30and 31). Hot forging more easily achieves a homoge-

neous and grain-refined microstructure, free of

defects. This is due to the dynamic recrystallisation

that occurs during hot forging (26).

The Limits of MetallographyOptical metallography is only the first step towards

the study of the microstructure of an alloy. A wide

variety of analytical techniques can be used alongside



500 µm

Fig. 20. Pt-5Au alloy: longitudinalsection (along the drawing direction)of a drawn cold worked wire(microhardness 190 ± 4 HV200 )

500 µm

Fig. 21. Pt-5Au alloy: transversesection of the drawn coldworked wire seen in Figure 20(microhardness 190 ± 4 HV200 )

50 µm

Fig. 22. Pt-5Au alloy: detail ofFigure 21 showing the deformationof the grains

500 µm

Fig. 23. Pt-5Au alloy: transverse sec-tion of the wire seen in Figure 21,after oxygen-propane flame anneal-ing (microhardness 104 ± 6 HV200 )

50 µm

Fig. 24. Pt-5Au alloy: detail ofFigure 23, showing therecrystallised grains

50 µm

Fig. 25. Pt99.99% wire:transverse sec-tion of the wireafter variousstages of draw-ing and anneal-ing (diameter0.35 mm;microhardness65 ± 3 HV100 )

200 µm

Fig. 19. 60Pt-25Ir-15Rh alloy: fromthe transverse section of an ingot,after various stages of work hard-ening and annealing (microhardness212 ± 5 HV200 ). Compare with theas-cast sample shown in Figure 6



Tem

pera

ture

, ºC

Iridium content, at%Pt 20 40 60 80 Ir

2200

1800

1400

1000

600

Pt 20 40 60 80 Ir

Iridium content, wt%

2454

1769

Liquid

α

α1 + α2

Fig. 26. Pt-Ir phase diagram showing a miscibilitygap at low temperatures (20)

Gold content, at%

Gold content, wt%

Tem

pera

ture

, ºC

Pt 20 40 60 80 Au

1800

1600

1400

1200

1000

800

Pt 20 40 60 80 Au

Liquid

α

α1 α2

Fig. 27. Pt-Au phase diagram showing a miscibilitygap at low temperature (25)

2 mm

Fig. 28. Pt-5Cu alloy: from a trans-verse section of a 19 mm × 19 mmingot, which was rod milled,annealed in a furnace and finishedat 10 mm × 10 mm by drawing. Thesample shows residual coarse grainmicrostructure from the as-castcondition and fractures along the baraxis (microhardness 208 ± 13 HV200 ).The small square shows the positionof the detail seen in Figure 29

200 µm

Fig. 29. Pt-5Cu alloy: detail ofFigure 28, with coarse grains andsmall opened cracks evident

2 mm

Fig. 30. Pt-5Cu alloy: from a trans-verse section of a 19 mm × 19 mmbar, which was hot hammered,torch annealed and finished bydrawing. The sample hashomogeneous microstructure withsmall grain size (microhardness200 ± 9 HV200 ). The small squareshows the position of the detailseen in Figure 31

it to provide a far more complete knowledge of the

microstructure. One of the most widely used

techniques is SEM. In addition to this, EDS allows the

relative concentration of the contained chemical ele-

ments to be determined, as shown in Figures 8–10.

Further studies can be performed by X-ray diffraction

(XRD), which reveals the different crystal phases

present in the alloy.

When working with platinum alloys, often only

very small specimens are available, therefore more

recent techniques may be required in order to study

them. One of these is the focused ion beam (FIB)

technique, which can produce microsections of a

specimen (27, 28). The microsections are then

analysed by other techniques, such as transmission

electron microscopy (TEM). In this case the details of

microstructure can be detected due to the high spatial

resolution of the technique. The crystal structure of

the primary and secondary phases can be studied by

electron diffraction. Another interesting technique is

nano-indentation, performed with micron-sized

indenters, which allows hardness measurements to

be performed with a spatial resolution far better than

that attainable with ordinary micro-indenters. The

data obtained from these measurements allows the

measurement of fundamental mechanical properties

of the alloy, such as the elastic modulus (Young’s

modulus) (29).

ConclusionsThe metallographic analysis of platinum alloys can

be profitably carried out by using a specimen prepa-

ration methodology based on the techniques used for

gold-based alloys. However, electrochemical etching

is required in order to reveal the alloy microstructure

and observe it by optical microscopy. A saturated

solution of sodium chloride in concentrated

hydrochloric acid can be successfully used for a great

many platinum alloys, both in the as-cast condition

and after work hardening. Optical metallography pro-

vides essential data on the alloy microstructure

which can be used in setting up the working proce-

dures. Other techniques can be used alongside it to

achieve a more complete knowledge of the material,

the effects of the working cycles on it, and to interpret

and explain any remaining problems.

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28 E. Bemporad, ‘Focused Ion Beam and Nano-MechanicalTests for High Resolution Surface Characterization: NotSo Far Away From Jewelry Manufacturing’, in “The SantaFe Symposium on Jewelry Manufacturing Technology2010”, ed. E. Bell, Proceedings of the 24th Symposiumin Albuquerque, New Mexico, USA, 16th–19th May,2010, Met-Chem Research Inc, Albuquerque, NewMexico, USA, 2010, pp. 50–78

29 D. J. Shuman, A. L. M. Costa and M. S. Andrade, Mater.Charact., 2007, 58, (4), 380

The AuthorPaolo Battaini holds a degree in nuclearengineering and is a consultant in fail-ure analysis for a range of industrialfields. He is responsible for researchand development at 8853 SpA inMilan, Italy, a factory producing dentalalloys and semi-finished products ingold, platinum and palladium alloys,and is currently a professor of preciousmetal working technologies at theUniversity of Milano-Bicocca, Italy.Professor Battaini is also a recipient ofthe Santa Fe Symposium® AmbassadorAward and regularly presents at theSanta Fe Symposium® on JewelryManufacturing Technology.



By Thomas J. Colacot

Johnson Matthey, Catalysis and Chiral Technologies,2001 Nolte Drive, West Deptford, New Jersey 08066,USA;


The 2010 Nobel Prize in Chemistry was awarded joint-

ly to Professor Richard F. Heck (University of Delaware,

USA), Professor Ei-ichi Negishi (Purdue University,

USA) and Professor Akira Suzuki (Hokkaido University,

Japan) for their work on palladium-catalysed cross-

coupling in organic synthesis. This article presents a

brief history of the development of the protocols for

palladium-catalysed coupling in the context of Heck,

Negishi and Suzuki coupling. Further developments in

the area of palladium-catalysed cross-coupling are also

briefly discussed, and the importance of these reac-

tions for real world applications is highlighted.

The 2010 Nobel Prize in chemistry was the third

awarded during the last ten years in the area of plat-

inum group metal (pgm)-based homogeneous cataly-

sis for organic synthesis. Previous prizes had been

awarded to Dr William S. Knowles (Monsanto, USA),

Professor Ryoji Noyori (Nagoya University, Japan) and

Professor K. Barry Sharpless (The Scripps Research

Institute, USA) in 2001, for their development of asym-

metric synthesis reactions catalysed by rhodium,

ruthenium and osmium complexes, and to Dr Yves

Chauvin (Institut Français du Pétrole, France),

Professor Robert H. Grubbs (California Institute of

Technology (Caltech), USA) and Professor Richard

R. Schrock (Massachusetts Institute of Technology

(MIT), USA) in 2005 for the development of the

ruthenium- and molybdenum-catalysed olefin

metathesis method in organic synthesis.

Figure 1 shows some of the researchers who have

made significant contributions in the area of palladi-

um-catalysed cross-coupling, including 2010 Nobel

laureate, Professor Akira Suzuki, during a cross-

coupling conference at the University of Lyon, France,

in 2007 (1).

Palladium-Catalysed ReactionsOrganometallic compounds of pgms are vitally

important as catalysts for real world applications in



The 2010 Nobel Prize in Chemistry:Palladium-Catalysed Cross-CouplingThe importance of carbon–carbon coupling for real world applications


synthetic organic chemistry. Chemists are continually

striving to improve the efficiency of industrial

processes by maximising their yield, selectivity and

safety. Process economics are also important, and

chemists work to minimise the number of steps

required and thereby reduce the potential for waste

and improve the sustainability of the process.

Homogeneous catalysis is a powerful tool which can

help to achieve these goals. Of the three Nobel Prizes

in pgm-based homogeneous catalysis, perhaps the

most impact in practical terms has been made by

palladium-catalysed cross-coupling (2).

In order for an area to be recognised for the Nobel

Prize, its real world application has to be demon-

strated within 20 to 30 years of its discovery. Although

the area of metal-catalysed cross-coupling was initi-

ated in the early 1970s, there were a very limited num-

ber of publications and patents in this area before the

1990s (see Figure 2). However, the area has grown

rapidly from 1990 onwards, especially since 2000.

In terms of the number of scientific publications,

patents and industrial applications, Suzuki coupling

is by far the largest area, followed by Heck,

Sonogashira and Stille coupling (Figure 2). Negishi

coupling is smaller in terms of the number of pub-

lications, but its popularity is growing due to the

functional group tolerance of the zinc reagent in

comparison to magnesium, in addition to its signifi-

cant potential in sp3–sp2 coupling, natural product

synthesis and asymmetric carbon–carbon bond form-

ing reactions (1).

The history and development of the various types

of palladium-catalysed coupling reactions have been

covered in detail elsewhere (3, 4). This short article

will focus on the practical applications of palladium-

catalysed coupling reactions.

Heck CouplingBetween 1968 and

1972, Mizoroki and

coworkers (5, 6) and

Heck and coworkers

(7–9) independently

discovered the use of

Pd(0) catalysts for

coupling of aryl, ben-

zyl and styryl halides

with olefinic com-



Fig. 1. From left: Professor Kohei Tamao (a significant contributor in Kumada coupling),Professor Gregory C. Fu (a significant contributor in promoting the bulky electron-richtert-butyl phosphine for challenging cross-coupling), Professor Akira Suzuki (2010 NobelPrize in Chemistry Laureate), Dr Thomas J. Colacot (author of this article) and ProfessorTamejiro Hiyama (who first reported Hiyama coupling) in front of a photograph ofProfessor Victor Grignard (who initiated the new method of carbon–carbon coupling) inthe library of the University of Lyon, France

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The

Nob

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ound

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n.Ph

oto:

Ulla

Mon

tan

pounds, now known as the Heck coupling reaction

(Scheme I) as Heck was the first to uncover the mech-

anism of the reaction.

The applications of this chemistry include the syn-

thesis of hydrocarbons, conducting polymers, light-

emitting electrodes, active pharmaceutical ingredi-

ents and dyes. It can also be used for the enantio-

selective synthesis of natural products.

Heck coupling has a broader range of uses than the

other coupling reactions as it can produce products

of different regio (linear and branched) and stereo

(cis and trans) isomers. Typically, olefins possessing

electron-withdrawing groups favour linear products

while electron-rich groups give a mixture of branched

and linear products.The selectivity is also influenced

by the nature of ligands, halides, additives and sol-

vents, and by the nature of the palladium source. The

reaction has recently been extended to include direct

arylation and hydroarylation, which may have future

potential in terms of practical applications. Heck cou-

pling also has the unique advantage of making chiral

C–C bonds,with the exception of α-arylation reactions.

The Negishi ReactionDuring 1976–1977,

Negishi and co-

workers (10–12) and

Fauvarque and Jutand

(13) reported the use

of zinc reagents in

cross-coupling reac-

tions.During the same

period Kumada et al.

(14–17) and Corriu

et al. (18) independ-

ently reported that nickel–phosphine complexes

were able to catalyse the coupling of aryl and alkenyl

halides with Grignard reagents. Kumada and cowork-

ers later reported (in 1979) the use of dichloro[1,1′-bis(diphenylphosphino)ferrocene]palladium(II)

(PdCl2(dppf)) as an effective catalyst for the cross-

coupling of secondary alkyl Grignard reagents with

organic halides (19). One common limitation to both

Ni- and Pd-catalysed Kumada coupling is that cou-

pling partners bearing base sensitive functionalities



8000

7000

6000

5000

4000

3000

2000

1000

0

Tota

l num

ber

of p

ublic

atio

ns

and

pate

nts

DecadesPre-1990 1991–2000 2001–2010

SuzukiHeckSonogashiraStilleNegishiBuchwald-HartwigKumadaHiyamaAlpha ketone arylation

Fig. 2. Growth in the number of scientific publications and patents on platinumgroup metal-catalysed coupling reactions

RX +R’ H

H H

R’ H

H R

Pd catalyst

Base

R, R’ = aryl, vinyl, alkylX = halide, triflate, etc.

Scheme I. The Heck coupling reaction

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Mon

tan

are not tolerated due to the nature of the organomag-

nesium reagents.

In 1982 Negishi and coworkers therefore carried out

a metal screening in order to identify other possible

organometallic reagents as coupling partners (20).

Several metals were screened in the coupling of an

aryl iodide with an acetylene organometallic reagent,

catalysed by bis(triphenylphosphine)palladium(II)

dichloride (PdCl2(PPh3)2). In this study, the use of

zinc, boron and tin were identified as viable counter-

cations, and provided the desired alkyne product in

good yields. The use of organozinc reagents as cou-

pling partners for palladium-catalysed cross-coupling

to form a C–C single bond is now known as the

Negishi reaction (Scheme II).

The Negishi reaction has been used as an essential

step in the synthesis of natural products and fine

chemicals (21–23).

Suzuki CouplingDuring the same

period as the initial

reports of the use of

palladium–phosphine

complexes in Kumada

couplings, the palla-

dium-catalysed cou-

pling of acetylenes

with aryl or vinyl

halides was concur-

rently disclosed by

three independent research groups, led by

Sonogashira (24), Cassar (25) and Heck (26).

A year after the seminal report on the Stille cou-

pling (27, 28), Suzuki picked up on boron as the last

remaining element out of the three (Zn, Sn and B)

identified by Negishi as suitable countercations in

cross-coupling reactions, and reported the palladium-

catalysed coupling between 1-alkenylboranes and

aryl halides (29) that is now known as Suzuki cou-

pling (Scheme III).

It should be noted that Heck had already demon-

strated in 1975 the transmetallation of a vinyl boronic

acid reagent (30). Perhaps the greatest acomplish-

ment of Suzuki was that he identified PdCl2(PPh3)2 as

an efficient cross-coupling catalyst, thereby demon-

strating the relatively easy reduction of Pd(II) to

Pd(0) during catalysis.

The Suzuki coupling reaction is widely used in

the synthesis of pharmaceutical ingredients such

as losartan. Its use has been extended to include

coupling with alkyl groups and aryl chlorides

through the work of other groups including Fu and

coworkers (31). Subsequent work from Buchwald,

Hartwig, Nolan, Beller and others, including Johnson

Matthey, has expanded the scope of this reaction.

Other Name Reactions in Carbon–CarbonCoupling In 1976, Eaborn et al. published the first palladium-

catalysed reaction of organotin reagents (32), fol-

lowed by Kosugi et al. in 1977 on the use of organotin

reagents (33,34). Stille and Milstein disclosed in 1978

the synthesis of ketones (27) under significantly

milder reaction conditions than Kosugi. At the begin-

ning of the 1980s, Stille further explored and improved

this reaction protocol, to develop it into a highly ver-

satile methodology displaying very broad functional

group compatibility (28).

In 1988, Hiyama and Hatanaka published their work

on the Pd- or Ni-catalysed coupling of organosilanes

with aryl halides or trifluoromethanesulfonates (tri-

flates) (35). Although silicon is less toxic than tin,

a fluoride source, such as tris(dimethylamino)-

sulfonium difluorotrimethylsilicate (TASF) (35) or cae-

sium fluoride (CsF) (36), is required to activate the

organosilane towards transmetallation. Professor S. E.

Denmark has also contributed significantly to this area.

Industrial ApplicationsIn the early 1990s the Merck Corporation was able to

develop two significant drug molecules, losartan, 11,



RZnY + R’X R–R’Pd catalyst

R, R’ = aryl, vinyl, alkylX = halide, triflate, etc.Y = halide

Scheme II. The Negishi coupling reaction

RBZ2 + R’X R–R’Pd catalyst

Base

R, R’ = aryl, vinyl, alkylX = halide, triflate, etc.Z = OH, OR, etc.

Scheme III. The Suzuki coupling reaction

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(also known as CozaarTM, for the treatment of hyper-

tension) (37) and montelukast, 22, (also known as

SingulairTM, for the treatment of asthma) (38, 39),

(Figure 3) using Suzuki and Heck coupling processes

respectively. This also increased awareness among

related industries to look into similar processes.

Today, coupling reactions are essential steps in the

preparation of many drugs. Recent reviews by Beller

(40) and by Sigman (41) summarise the applications

of Pd-catalysed coupling in the pharmaceutical,agro-

chemical and fine chemicals industries. Apart from

the major applications in the pharmaceutical and

agrochemical industries (the boscalid process is the

world’s largest commercial Suzuki process), cross-

coupling is also being practiced in the electronics

industry for liquid crystal and organic light-emitting

diode (OLED) applications in display screens (42,

43).

The research and development group at Johnson

Matthey’s Catalysis and Chiral Technologies has devel-

oped commercial processes for preformed catalysts

such as PdCl2(dtbpf) (Pd-118), 33, (44–46), L2Pd(0)

complexes, 44, (47) and precursors to twelve-electron

species such as [Pd(µ-Br)tBu3P]2 (Pd-113), 55, (48)

and LPd(η3-allyl)Cl, 66, (49, 50) (Figure 4). These cata-

lysts are all highly active for various cross-coupling

reactions which are used for real world applications.

More details on the applications of these catalysts

are given elsewhere (48, 51, 52). A special issue of

Accounts of Chemical Research also covered recent

updates of these coupling reactions from academia

in detail (53).



PdBr

PtBu2

3

Fe

PtBu2

Pd

Cl

ClL L

4

tBu3P–Pd Pd–PtBu3

Br

5Pd

Cl

P

6

4a L = PtBu34b L = PtBu2Np4c L = PCy34d L = Q-Phos4e L = Ata-Phos4f L = P(o-tolyl)34g L = PPhtBu2

Fe

PtBu2

Ph

PhPh

Ph

Q-Phos ligand

Me2N

Ata-Phos ligand

PtBu2

Ph

2 Montelukast 1 Losartan

Fig. 4. Examples of highly active Pd cross-coupling catalysts developed and commercialised by Johnson Matthey

Fig. 3. Structures of losartan and montelukast

In order to address the issue of residual palladium

in the final product, several solid-supported

preformed palladium complexes have been devel-

oped and launched onto the catalyst market

(54–56).

ConclusionsPalladium-catalysed cross-coupling is of great impor-

tance to real world applications in the pharmaceu-

tical, agrochemicals, fine chemicals and electronics

industries. The area has developed quite rapidly

beyond the work of Heck, Negishi and Suzuki,

though all three reactions are widely used. Academic

groups such as those of Beller, Buchwald, Fu, Hartwig

and Nolan as well as industrial groups such as that

at Johnson Matthey, are now developing the field even

further. Buchwald-Hartwig coupling has become par-

ticularly important for developing compounds con-

taining carbon–nitrogen bonds for applications in

industry, as well as α-arylation of carbonyl com-

pounds such as ketones, esters, amides, aldehydes

etc., and nitriles (57). The significant growth of cross-

coupling reactions can be summarised in Professor

K. C. Nicolaou’s words:

“In the last quarter of the 20th century, a new

paradigm for carbon–carbon bond formation has

emerged that has enabled considerably the prowess

of synthetic organic chemists to assemble complex

molecular frameworks and has changed the way

we think about synthesis” (58).

More detailed articles summarising the history of

cross-coupling in the context of the 2010 Nobel Prize

in Chemistry with an outlook on the future of cross-

coupling will be published elsewhere (59, 60).



Glossary

Ligand Name

Ata-Phos p-dimethylaminophenyl(di-tert-butyl)phosphine

Cy cyclohexyl

dppf 1,1′-bis(diphenylphosphino)ferrocene

dtbpf 1,1′-bis(di-tert-butylphosphino)ferrocene

Np neopentyl

Ph phenyl

Q-Phos 1,2,3,4,5-pentaphenyl-1′-(di-tert-butylphosphino)ferrocenetBu tert-butyl

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51 T. J. Colacot and S. Parisel, ‘Synthesis, CoordinationChemistry and Catalytic Use of dppf Analogs’, in“Ferrocenes: Ligands, Materials and Biomolecules”, ed.P. Stepnicka, John Wiley & Sons, New York, USA, 2008

52 T. J. Colacot, ‘Dichloro[1,1’-bis(di-tert-butylphosphino)-ferrocene]palladium(II)’, in “e-EROS Encyclopedia ofReagents for Organic Synthesis”, eds. L. A. Paquette,D. Crich, P. L. Fuchs and G. Molander, John Wiley & Sons,published online 2009

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The AuthorDr Thomas J. Colacot, FRSC, is aResearch and Development Managerin Homogeneous Catalysis (Global) ofJohnson Matthey’s Catalysis andChiral Technologies business unit.Since 2003 his responsibilities includedeveloping and managing a new cat-alyst development programme, cat-alytic organic chemistry processes,scale up, customer presentations andtechnology transfers of processesglobally. He is a member of PlatinumMetals Review’s Editorial Board,among other responsibilities. He hasco-authored about 100 publicationsand holds several patents.



Reviewed by Ian J. S. Fairlamb

Department of Chemistry, University of York, Heslington,York YO10 5DD, UK;


The 12th Dalton Discussion (DD12) conference was

held at Durham University, UK, from 13th–15th

September 2010 (1). It was the first Dalton Discussion

to have been jointly organised by the Dalton and

Organic Divisions of the Royal Society of Chemistry

(RSC). A special issue of Dalton Transactions, con-

taining refereed papers (both original and perspective

articles), accompanied all the presentations at the

conference (2). The DD12 meeting was supported by

generous sponsorship from BP, Pfizer and the Dalton

and Organic Divisions of the RSC, and poster prizes

were provided by Springer, Dalton Transactions and

Catalysis Science and Technology.

The principal aim of DD12 was to bring together

both organic and inorganic chemists from around the

world to highlight and discuss important aspects rele-

vant to the design, development and application of

late transition metal-catalysed protocols involving the

activation of either carbon–X (X = halogen or pseudo-

halogen) or carbon–hydrogen bonds. The investi-

gation of mechanism and synthetic applications of

catalytic processes by both experimental and theo-

retical methods underpinned many of the oral and

poster contributions at the conference.

Common themes discussed at DD12 included:

• Ligand design and kinetic studies of catalytic

processes involving C–H and C–X activation;

• New opportunities in C–X activation;

• Fundamental experimental aspects of C–X and

C–H activation;

• Mechanistic and theoretical aspects of C–X and

C–H activation.

It was quite fortuitous that DD12 occurred just a

few weeks prior to the announcement on 6th October

2010 that the Nobel Prize in Chemistry 2010 would be

awarded to Professors Richard F. Heck, Ei-ichi Negishi

and Akira Suzuki for work in the field of palladium-

catalysed cross-coupling reactions in organic synthe-

sis (3), which highlights the general importance and

timeliness of the topic.

Over one hundred delegates attended DD12 from

across Europe, Asia, the Middle East and North

America. Both academic and industrial groups were



Dalton Discussion 12: CatalyticC–H and C–X Bond Activation


represented at the conference, with around 25% of

attendees being from major industrial organisations.

The DD12 meeting comprised eight single sessions

run over three days. Individual sessions began with

either a Keynote lecture or an invited lecture. These

were followed by three five-minute contributed pre-

sentations. With the exception of the sixth session

(see below), questions were taken during the lively

and lengthy discussions held after all of the session

lectures had taken place.

Ligand DesignProfessor Todd Marder (Durham University, UK)

chaired the first session of the meeting. Professor

Hans de Vries (DSM Pharmaceutical Products, The

Netherlands) gave the Keynote lecture, which pro-

vided an overview of cross-coupling reactions and

issues of ‘ligand design’ versus ‘ligand-free’ catalysis.

His lecture nicely set the tone of the meeting and

stimulated lots of discussion; for example, on the

nature of the catalytically active species and the

role of palladium nanoparticles. Professor de Vries

then went on to present several mechanisms for the

modified Ullmann reaction, highlighting the impor-

tance of copper(III) species, but also issues surround-

ing the complex catalytic reaction systems.

A careful study of manganese-catalysed C–H oxi-

dation with hydrogen peroxide showed that spe-

cially designed multidentate ligands were oxidised to

pyridine-2-carboxylic acid prior to catalytic substrate

oxidation, which explains the observed catalytic

activity (Scheme I). This work by Wesley R. Browne

(University of Groningen, The Netherlands) showed

that some caution should be exerted in ligand design,

metal catalysis and reaction mechanism analysis,

especially where the ligand can change chemical

form under the catalytic reaction conditions used.

Selective CatalysisThe second session was chaired by Warren B. Cross

(University of Leicester, UK) who introduced a

Keynote lecture from Professor Aiwen Lei (Wuhan

University, China). Professor Lei discussed selective

oxidative cross-coupling using palladium(II) catalysis

(with a suitable oxidant) between two different

nucleophiles (for example Process A, Scheme II) and



Mn/H2O2

OH

N N

N

N N

Ligand oxidationN

CO2HMn/H2O2

HO

Activecatalystspecies

Scheme I. Ligand degradation in a manganese-catalysed oxidation process

+

Process AM

R1

Process BX

R1

H

R1Process C

H

R2Pd catalyst

R1

R2

M = metalX = halogen or pseudohalogen

or:

or:

Scheme II.New catalyticcross-couplingprocesses withactivated orunactivated arenes

went on to elaborate on issues surrounding the rates

of reductive elimination processes. Crucially, fast

reductive elimination and transmetallation rates were

found to determine the selectivity of the hetero-

coupling reaction.

George Fortman (University of St Andrews, UK)

discussed work on the synthesis of gold–acetylides

formed by alkyne C–H activation. The serendipitous

discovery of a palladium-catalysed regioselective

C–H functionalisation of 2-pyrones was then reported

by Professor Fairlamb. Two catalysts were used in this

work,namely trans-Pd(Br)N-Succ(PPh3)2 and Pd2(dba-

4-OMe)3 (N-Succ = succinimide; dba-4-OMe = 1,5-bis-

(4′-methoxyphenyl)penta-1E,4E-dien-3-one).

The third session of the meeting was chaired by

Professor Fairlamb, and began with a Keynote lecture

by Professor Jennifer Love (The University of British

Columbia, Canada). Love presented a brief overview

of carbon–fluorine activation processes including

cross-coupling reactions of polyfluoroarenes. She

focused on the development of nickel and platinum

catalyst systems for arylboronic acid cross-coupling

with fluoroarenes containing ortho-directing groups.

This presentation was followed by Professor Philippe

Dauban (Centre National de la Recherche

Scientifique (CNRS), France), who presented studies

of catalytic aminations involving nitrene insertion

into C–H bonds (Scheme III). The selective C–H

functionalisation of secondary methylene carbon

centres in the presence of other secondary sites was

a particular highlight.

During the discussion session of these lectures,

several of the pharmaceutical chemists present at the

meeting debated the role of fluoroaryl groups in

pharmaceutical compounds. Several viable synthetic

methods for incorporating fluoro substituents into

arenes were highlighted.

Mechanistic AspectsThe fourth session of DD12 was chaired by Professor

Susan Gibson (Imperial College London, UK), and

began with an invited lecture by John M. Brown

(Oxford University, UK). Brown introduced anilide

activation of adjacent C–H bonds in the palladium-

catalysed Fujiwara-Moritani reaction using catalytic

Pd(OAc)2 in the presence of tosic acid and p-benzo-

quinone. Kinetic aspects such as induction periods

and palladacycle formation were presented as well as

synthetic aspects. During the discussion session a

number of mechanistic aspects of these processes

were raised, which led to David (Dai) Davies

(University of Leicester, UK) defining the ambiphilic

metal ligand activation (AMLA) process in which the

number of atoms thought to be involved in the transi-

tion state is specified, as illustrated in Scheme IV for

AMLA-4 (4 electrons) and AMLA-6 (6 electrons)



Iodine(I)

R’R

S(S)NH2 + Iodine(III)

Rh*

Concertedor stepwise?

Rh*=NS(S)

H

R’R

NHS(S)

Terpenes orpolycyclic systems

Yield ≤91%de ≤99%

S(S)NH2 =

NH2S

O

N SO2-p-Tol

Rh* =O

O

N

O O

Rh RhRh2((S)-nta)4nta = nitrilotriacetate

Scheme III. Selectivecarbon–hydrogenactivation-catalyticamination usingrhodium catalysis

intermediates which are of general relevance to C–H

activation. The concerted metalation-deprotonation

(CMD) is identical to AMLA-6.

Esteban P. Urriolabeitia (University of Zaragoza,

Spain) reported stoichiometric and catalytic

regioselective C–H functionalisations including a

palladium-catalysed oxidative etherification of imino-

phosphoranes. Finally, a combined theoretical and

experimental study on the use of ruthenium vinyli-

dene complexes as catalysts for carbon–oxygen bond

formation was presented by Jason M. Lynam

(University of York, UK). The role of carboxylate

‘acetate’ ligands was discussed, and a variant of the

AMLA/CMD mechanism proposed, namely the ligand-

assisted-proton shuttle (LAPS) (Scheme V).

The fifth session was chaired by Anthony Haynes

(The University of Sheffield, UK). Professor Zhang-Jie

Shi (Peking University, China) gave an interesting

presentation, particularly the unusual results of a

‘metal-free’ coupling of an aryl halide with an arene

using potassium tert-butoxide and 1,10-phenanthro-

line (4).

Dai Davies went on to present alkyne insertion

reactions of cyclometallated pyrazole and imine

complexes of iridium, rhodium and ruthenium, with

emphasis on establishing substrate/catalyst/product

correlations through detailed structural and spectro-

scopic studies. The last speaker of the session, Xavi

Ribas (Universitat de Girona, Spain), discussed reduc-

tive elimination from a ‘model’ aryl–Cu(III)–halide

species which was triggered by a strong acid, and its

relevance to the mechanism of Ullmann-type cou-

plings (Scheme VI).

C–H ActivationThe sixth session was chaired by Professor Peter

Scott (The University of Warwick, UK), and the first

invited lecture was from Professor Robin Bedford

(University of Bristol, UK). Bedford presented an

introduction to the field of ‘C–H activation’, and went

on to discuss mild and selective ‘solvent-free’ aro-

matic C–H functionalisation/halogenation reactions

catalysed by Pd(OAc)2. The second lecture was

given by Professor Fairlamb on surface-catalysed



++

O

HN

O

HNPd(OAc)2, p-TsOH, butyl

acrylate, p-benzoquinone

CO2Bu

LnMR’

R

H

++LnM

R’

R

H

++

LnM

R’

R H

++

LnMX

R

H

O

O

Oxidativeaddition

σ-Bondmetathesis

Ambiphilic metal ligand activation(AMLA)

AMLA-6*AMLA-4

*AMLA-6 is essentially identical toconcerted metalation deprotonation(CMD)

R’ = H, hydrocarbyl, borylX = heteroatom with lone pair(s)

O H

RuO

R

O

[Ru]O

H

R

O O

[Ru] C

H

R

[Ru]=Ru(κ2-OAc)(PPh3)2

Scheme IV. Alkenylationchemistry (top); ambiphilicmetal ligand activation(AMLA) and concertedmetalation-deprotonation(CMD) mechanisms forcarbon–hydrogen activation(bottom)

Scheme V. Ligand-assisted-protonshuttle (LAPS)mechanism

Suzuki-Miyaura cross-coupling over palladium nano-

particles stabilised by polyvinylpyrrolidinone (PVP).

This work, in collaboration with Professor Adam Lee,

gave details about the reaction mechanism, including

results from kinetic studies, X-ray photoelectron spec-

troscopy (XPS) and X-ray absorption spectroscopy

(XAS), of a heterogeneous surface-catalysed Suzuki

cross-coupling (Figure 1). Extended X-ray absorption

fine structure (EXAFS) measurements proved particu-

larly informative in showing that palladium nanopar-

ticles do not change size in a typical Suzuki-Miyaura

cross-coupling. Finally, Professor Yoshiaki Nakao

(Kyoto University, Japan) presented a nickel-catalysed

alkenylation of aromatic C–H bonds in indoles and

pentafluorobenzene.

The seventh session was chaired by Jason M. Lynam

and the Keynote lecture was given by Professor

William D. Jones (University of Rochester, USA).

Professor Jones discussed various kinetic and ther-

modynamic aspects of C–H bond activation by transi-

tion metals. A key focus of the lecture was placed on

the ortho-fluorine effect by drawing on both rhodium–

carbon and carbon–hydrogen bond energy correla-

tions in a series of fluorinated aromatic hydrocarbons

(Figure 2). Professor Robin Perutz (University of

York, UK) delivered a presentation on studies in col-

laboration with Professor Odile Eisenstein (Université

Montpellier II, France), discussing the effect of ortho-

fluorine substituents on Pd/C catalysed C–C bond

formation, particularly C–H functionalisation and the

CMD/AMLA-6 mechanism. Together, the Jones and

Perutz presentations showed that one should con-

sider both C–H acidity and metal–carbon (aryl)

bond strengths when explaining the regioselective

C–H functionalisation accelerated by ortho-fluorine

substituents.

Theoretical AspectsThe final session was chaired by Professor Odile

Eisenstein, and began with an invited lecture by

Professor Stuart Macgregor (Heriot-Watt University,

UK). Macgregor delivered an introduction to theo-

retical approaches, following previous comments on

the strengths, weaknesses and pitfalls of certain

aspects of density functional theory (DFT) calcula-

tions. More detailed computational studies were

presented on catalytic alkene hydroarylation with

[CpIr((κ2-OAc)(PH3)]+, with particular emphasis on

the AMLA-6 mechanism. This once again highlighted

the key role played by the ‘flexible’ acetate ligand.

Eric Clot (Université Montpellier II, France) went on

to present a DFT study of the mechanism of Pd(PR3)-

catalysed benzocyclobutene formation via C(sp3)–H

activation. In the final presentation, Professor Mike



N

N N

CH3

H H

( )3

CuIII

X

+( )3

CF3SO3H (1.5 equiv),CH3CN, 298 K, <1 h

X = Cl or Br

N

N N

H3C

H H + [CuI(CH3CN)4]+

( )3

X

( )3

H

+

CF3SO3– (TFO–)

Scheme VI. Aryl–X reductive elimination from an aryl–Cu(III)–X species via protonation with triflic acid

Ar1X

Ar2B(OH)2

Ar1–Ar2

Heterogeneous catalytic cycle

Kinetically stablemetallic Pdnanoparticles(<5 nm)

Fig. 1. Palladium-surface catalysedSuzuki-Miyaura cross-couplings (From A. F. Lee et al., in (2). Reproduced by permission of The Royal Society ofChemistry)

George (The University of Nottingham, UK) presented

a combined experimental (fast time-resolved infrared

spectroscopy (TRIR)) and theoretical investigation of

the C–H activation of cyclic alkanes by cyclopentadi-

enyl rhodium(I) carbonyl complexes. He highlighted

the inherent mechanistic differences in C–H activa-

tion of linear versus cyclic alkanes by half-sandwich

rhodium complexes. Interestingly, C–H activation in

cyclic alkanes depends primarily on the strength of

alkane–metal binding. Note that this paper appeared

in a later issue of Dalton Transactions (5).

Poster PrizesFollowing the conference dinner in the famous

Durham Castle, Professors Love and Perutz awarded

four poster prizes. The poster content of the awardees

(Figure 3)highlighted the breadth of subjects covered

and the high standard of all of the posters presented

at the meeting. The winning posters were:

• ‘Hydrodefluorination of Fluoroaromatics by

[RuH2(CO)(NHC)(PPh3)2]: An Explanation for

the 1,2-Regioselectivity’, Julien Panetier (Heriot-

Watt University, UK)

• ‘Development of Chiral 4-(DAAP)-N-oxide

Catalysts for the Sulfonylative Kinetic Resolution

of Amines’, Toritse Bob-Egbe (Imperial College

London,UK)

• ‘Reversible Reactions Across the M–C Bond of

Lanthanide NHC Complexes to Form New N–E

and C–E Bonds’, Anne Germeroth (University of

Edinburgh, UK)

• ‘Novel Multidentate Phosphine-Alkene Ligands

for Catalysis’, Amanda Jarvis (University of York,

UK)

Concluding RemarksFrom the oral presentations, numerous posters and

lively discussions at the DD12 meeting, there was

overwhelming evidence that a better understanding

of the mechanisms of metal-catalysed C–X and C–H

functionalisation processes is emerging. Quite strik-

ingly, studies in inorganic and organometallic coordi-

nation chemistry, theoretical and kinetic studies, new

synthetic methodologies and applications are driving

this understanding. The platinum group metals play

an important role in many of the catalytic processes

under discussion.

As a first joint discussion conference between the

RSC Dalton and Organic Divisions, it was a great suc-

cess, and showed quite clearly that both the organic



Fn

FF

[Rh] HR3P

Fn

F

[Rh] HR3P

[Rh] HR3P

8 kcal mol–1

5 kcal mol–1ortho-fluorine effect

[Rh] = Tp’RhTp’ = tris(3,5-dimethylpyrazolyl)borate

RRh–C /C–H = 2.15Fig. 2. The ortho-fluorine effect inpromoting carbon–hydrogen activation.RRh–C /C–H = slope of line on plot ofRh–C vs. C–H bond strength (FromT. Tanabe et al., in (2). Reproduced bypermission of The Royal Society ofChemistry)

Fig. 3. Poster prize winners of Dalton Discussion 12:Julien Panetier (Heriot-Watt University), ToritseBob-Egbe (Imperial College London), Anne Germeroth(University of Edinburgh) and Amanda Jarvis(University of York)

and inorganic communities need to work together to

deliver powerful, clean and efficient methods for the

preparation of functionalised organic building blocks

and fine chemicals.

References1 RSC Conferences and Events, Dalton Discussion 12:

Catalytic C–H and C–X Bond Activation (DD12): http://www.rsc.org/ConferencesAndEvents/RSCConferences/dd12/index.asp (Accessed on 31 December 2010)

2 Dalton Discussion 12: Catalytic C–H and C–X bondactivation (DD12), Dalton Trans., 2010, 39, (43),10321–10540

3 The Nobel Prize in Chemistry 2010: http://nobelprize.org/nobel_prizes/chemistry/laureates/2010/ (Accessed on 31December 2010)

4 C.-L. Sun, H. Li, D.-G. Yu, M. Yu, X. Zhou, X.-Y. Lu,

K. Huang, S.-F. Zheng, B.-J. Li and Z.-J. Shi, NatureChem., 2010, 2, (12), 1044

5 M. W. George, M. B. Hall, P. Portius, A. L. Renz, X.-Z.Sun, M. Towrie and X. Yang, Dalton Trans., 2011, 40,(8), 1751

The ReviewerProfessor Ian Fairlamb is currently aFull Professor in Organic Chemistry atthe University of York, UK, and hasresearch interests in catalysis, syntheticchemistry, mechanistic understanding,nanocatalysis, metals in medicine, andapplications of catalysis in chemicalbiology. In 2004, he was awardedboth a Royal Society UniversityResearch Fellowship and the RoyalSociety of Chemistry Meldola Medaland Prize for outstanding contributionsto the field of palladium chemistryin synthesis.



By Alison Cowley

Johnson Matthey Precious Metals Marketing, Orchard

Road, Royston, Hertfordshire SG8 5HE, UK

and Brian Woodward*

Johnson Matthey Medical Products, 12205 World Trade

Drive, San Diego, California 92128, USA;

**EE--mmaaiill:: wwooooddwwbbkk@@jjmmuussaa..ccoomm

The world’s growing population demands increasing

access to advanced healthcare treatments. Platinum is

used to make essential components for a range of

medical devices, including pacemakers, implantable

defibrillators, catheters, stents and neuromodulation

devices. The properties of platinum which make it

suitable for medical device applications include its bio-

compatibility, inertness within the body, durability, elec-

trical conductivity and radiopacity.Components can be

manufactured in a variety of forms, from rod, wire and

ribbon to sheet and foil, plus high-precision microma-

chined parts. As well as biomedical device compo-

nents,platinum also finds use in anticancer drugs such

as cisplatin and carboplatin.

Introduction

According to the United Nations Environment

Programme (UNEP), the global population will reach

over 9 billion by 2050 with nearly 90% of the world’s

people located in developing countries (FFiigguurree 11) (1).

Since the early 1970s, platinum has been used in a

variety of medical devices for people around the

world suffering from such ailments as heart disease,

stroke, neurological disorders, chronic pain and other

life threatening conditions. In 2010, some 175,000 oz

of platinum are estimated to have been used in bio-

medical devices, of which around 80 per cent was for

established technologies such as guidewires and car-

diac rhythm devices. The remaining 20 per cent was

used in newer technologies, such as neuromodula-

tion devices and stents. In addition, over 25,000 oz of

platinum are used annually in anticancer drugs (2).

With an ageing and increasing world population,

there will be an increasing demand for healthcare

products and services that use components made

from platinum, other platinum group metals (pgms)

and their alloys. Increasing access to healthcare and

advanced medical treatments in developing coun-

tries means that platinum contributes to improving

the quality of life of people around the world.



A Healthy Future: Platinum inMedical ApplicationsPlatinum group metals enhance the quality of life of the global population



mailto:[email protected]

The Advantages of Platinum for

Biomedical Uses

The chemical, physical and mechanical properties of

platinum and its alloys make them uniquely suitable

for a variety of medical applications. Agnew et al. (3)

and Brummer et al. (4) carried out studies which con-

firmed the low corrosivity, high biocompatibility and

good mechanical resistance of platinum and plat-

inum alloys that are used for medical applications.

Platinum’s biocompatibility makes it ideal for

temporary and permanent implantation in the body,

a quality which is exploited in a variety of treatments.

As a metal, it can be fabricated into very tiny, com-

plex shapes and it has some important properties not

shared by base metals. It is inert, so it does not cor-

rode inside the body unlike metals such as nickel

and copper, which can sometimes cause allergic

reactions. Modern, minimally-invasive medical tech-

niques often use electricity to diagnose and treat

patients’ illnesses, and platinum’s conductivity makes

it an ideal electrode material. It is also radiopaque,

so it is clearly visible in X-ray images, enabling doc-

tors to monitor the position of the device during

treatment. Some examples of areas where pgms are

used in medical devices, together with some of the

manufacturers currently active in the medical device

market, are shown in TTaabbllee II.

For more than forty years platinum alloys have

been employed extensively in treatments for coronary

artery disease such as balloon angioplasty and stent-

ing where inertness and visibility under X-ray are

crucial. In the field of cardiac rhythm disorders,

platinum’s durability, inertness and electrical conduc-

tivity make it the ideal electrode material for devices

such as pacemakers, implantable defibrillators and

electrophysiology catheters. More recently, its unique

properties have been exploited in neuromodulation

devices (including “brain pacemakers”, used to treat

some movement disorders, and cochlear implants, to

restore hearing), and in coils and catheters for the

treatment of brain aneurysms.

Platinum in Biomedical Applications

Devices for Cardiac Rhythm Management

Abnormalities of the heart’s rhythm are common,

often debilitating, and sometimes fatal. For example,

bradycardia is a condition in which the heart’s

“natural pacemaker” is set too slow, resulting in

fatigue, dizziness and fainting. Other patients may

be at risk of sudden cardiac death, a condition in

which the heart’s lower chambers (the ventricles)

“fibrillate”, or pulse in a rapid and uncoordinated

manner. This prevents the heart from pumping

blood and leads rapidly to death unless the victim

receives cardioversion (a strong electric shock to the

heart, which restores normal rhythm).

These and other cardiac rhythm disorders can

now be managed very successfully using implanted



8

6

4

2

0

Glo

bal p

op

ula

tion,

estim

ate

s and

pro

ject

ions

(bill

ions)

Developed countries

Developing countries

1750 1800 1850 1900 1950 2000 2050

Year

Fig. 1. Trendsin population,developed anddevelopingcountries, between1750–2050(estimates andprojections) (1)(Image: HugoAhlenius, Nordpil)

devices such as artificial pacemakers (5, 6) and

implantable cardioverter defibrillators (ICDs) (7–9).

These consist of a “pulse generator”, a small box

containing a battery and an electronic control sys-

tem which is implanted in the chest wall, and one

or more leads which run through a large vein into

the heart itself. The electrodes on these leads deliver

electrical impulses to the heart muscle – in the case

of a pacemaker, these ensure that the heart beats

regularly and at an appropriate pace, while in the

case of an ICD, a much stronger electrical shock is

delivered as soon as the device detects a dangerously

irregular heartbeat. Each lead typically has two or

more electrodes made of platinum-iridium alloy,

while platinum components are also used to con-

nect the pulse generator to the lead (FFiigguurree 22).

Catheters and Stents

Catheters are flexible tubes which are introduced

into the body to help diagnose or treat illnesses

such as heart disease (10–13). The doctor can per-

form delicate procedures without requiring the

patient to undergo invasive surgical treatment,

improving recovery time and minimising the risk of

complications. Many catheters incorporate platinum

components: marker bands and guidewires, which

help the surgeon guide the catheter to the treatment

site, or electrodes, which are used to diagnose and

treat some cardiac rhythm disorders (arrhythmias).

One of the most common coronary complaints in

the developed world is atherosclerosis, the “furring

up” of the artery walls with fatty deposits, which can

lead to angina and heart attack (14). Blockages in the

coronary arteries are often treated using a procedure

called “percutaneous transluminal coronary angio-

plasty” (PTCA, also known as balloon angioplasty)

(15, 16). This treatment uses a catheter with a tiny bal-

loon attached to its end, which is guided to the treat-

ment site then inflated, crushing the fatty deposits

and clearing the artery. Afterwards, a small tubular

device called a stent (FFiigguurree 33) is usually inserted in

order to keep the newly-cleared artery open.

The advent of the implantable metal stent to prop

open the artery after angioplasty reduced the

occurrence of restenosis (re-narrowing of the artery)

by more than 25 per cent. In 2003 the US FDA

approved the first drug-eluting stent for use within

the USA (17). This type of stent is aimed at further

lowering the rate of restenosis following angioplasty

procedures.

Platinum’s role in PTCA is to help ensure that the

balloon is correctly located. First, the surgeon uses a

guidewire to direct the balloon to the treatment site.

This guidewire is made of base metal for most of its

length, but has a coiled platinum-tungsten wire at

its tip, which makes it easier to steer and ensures

that it is visible under X-ray. Platinum is also used in

marker bands, tiny metal rings which are placed

either side of the balloon in order to keep track of

its position in the body.

Stents are usually made of base metals (typically

stainless steel or cobalt-chromium). However, in

2009, the American device manufacturer Boston

Scientific introduced a cardiac stent made of a plat-

inum chromium alloy (18–20). This stent has been

approved in Europe, and the company is currently



TTaabbllee II

MMaarrkkeettss ffoorr MMeeddiiccaall DDeevviicceess aanndd tthhee MMaajjoorr DDeevviiccee CCoommppaanniieess

MMeeddiiccaall ddeevviiccee mmaarrkkeettss EExxaammpplleess ooff aapppplliiccaattiioonn aarreeaass MMaajjoorr mmeeddiiccaall ddeevviiccee ccoommppaanniieess

Surgical instrumentation Arthroscopic; ophthalmology; Boston Scientific; Johnson &

endo-laparoscopic; electro-surgical Johnson; Stryker; Tyco

Electro-medical implants Pacemakers; defibrillators; hearing Boston Scientific; Biotronik;

assist devices; heart pumps Medtronic; St. Jude Medical

Interventional Stents; angioplasty; catheter Boston Scientific; Abbott Vascular;

ablation; distal protection Johnson & Johnson; Medtronic

Orthopaedics Spinal fixation; hip implants; Biomet; Johnson & Johnson;

knee implants Stryker; Zimmer

seeking approval from the US Food & Drugs

Administration (FDA).

Catheters containing platinum components are

also used to detect and treat some types of cardiac

arrhythmia (21, 22). Devices called electrophysiology

catheters (23), which contain platinum electrodes,

are used to map the electrical pathways of the

heart so that the appropriate treatment – such as a

pacemaker – can be prescribed.

Other catheters with platinum electrodes are used

for a minimally-invasive heart treatment known as

radio-frequency (RF) ablation (24–26). Arrhythmias

are often caused by abnormalities in the conduction

of electricity within the heart, and it is often possible



Pt-Ir, MP35N® orstainless steelmachined parts forterminal connector

Pt or Pt-Ir throughwires for multi-pinhermetic seal, insidethe seal housing(0.015” (0.381 mm) and 0.013”(0.330 mm)) Pt or Pt-Ir wire and

ribbon multifilarcoils for high-voltage shockingelectrodes

Pt-Ir alloy rings forshocking electrodes

TiNi-coated Pt-Irmachined partsfor passivefixation leads

Porous TiNi-coatedPt-Ir helix and postassembly for activefixation leads

Fig. 2. An implantable cardioverter defibrillator, showing the components that are made from platinum orplatinum group metal alloys

Balloonsupportingthe stent

Stent (stainlesssteel, Co-Cr,Co-Cr with Pt,or nitinol)

Guidewire withcoiled Pt-W tip

Marker band (Pt,Pt-Ir or Au)

Fig. 3. A balloon-mounted stent used inpercutaneous transluminal coronaryangioplasty (PTCA, or balloon angioplasty)procedures (Copyright © Abbott VascularDevices)

to cauterise part of the heart muscle in order to

restore normal heart rhythm. For example, ablation

is increasingly used to treat a very common heart

problem called atrial fibrillation, in which the upper

chamber of the heart (the atrium) quivers rapidly and

erratically. Using a catheter equipped with platinum-

iridium electrodes, the surgeon “ablates” or makes

small burns to the heart tissue, causing scarring,

which in turn blocks the superfluous electrical

impulses which trigger the fibrillation.

Neuromodulation Devices

Neuromodulation devices deliver electrical impulses

to nerves and even directly to the brain, treating dis-

orders as varied as deafness, incontinence (27, 28),

chronic pain (29) and Parkinson’s disease (30). Many

of these devices are based on an extension of heart

pacemaker technology, and they are sometimes

referred to as “brain pacemakers” (31). Like heart

pacemakers, they have platinum-iridium electrodes

and may also incorporate platinum components in

the pulse generator.

There are a number of different types of neurostim-

ulation, depending on the condition that is being

treated. Spinal cord stimulation (the commonest

neuromodulation therapy) is used to treat severe

chronic pain, often in patients who have already

had spinal surgery. Small platinum electrodes are

placed in the epidural space (the outer part of the

spinal canal) and connected to an implanted pulse

generator. The patient can turn the stimulation off

and on, and adjust its intensity.

In deep brain stimulation (DBS) (32–34), the elec-

trodes are placed in the brain itself. As well as pain,

DBS may be used to treat movement disorders such

as Parkinson’s disease, and it is being investigated as a

potential treatment for a wide range of other illnesses,

including epilepsy and depression. Epileptic patients

can also be treated using a vagus nerve stimulation

device (the vagus nerve is situated in the neck).

A cochlear implant (35–38) is used to restore hear-

ing to people with moderate to profound hearing

loss (many patients receive two implants, one in each

ear). A typical device consists of a speech processor

and coil, which are worn externally behind the ear,

an implanted device just under the skin behind the

ear, and a platinum electrode array which is posi-

tioned in the cochlea (the sense organ which

converts sound into nerve impulses to the brain).

The speech processor captures sound and converts it

to digital information, which is transmitted via the

coil to the implant. This in turn converts the digital

signal into electrical impulses which are sent to the

electrode array in the cochlea, where they stimulate

the hearing nerve. These impulses are interpreted by

the brain as sound. It is believed that around 200,000

people worldwide have received one or more

cochlear implants.

At present, neuromodulation is expensive and is

only available in a small number of specialist centres;

even in developed countries only a small proportion

of potentially eligible patients receive this treatment.

However, neuromodulation can be used to help

patients with common and sometimes difficult to

treat conditions (such as chronic pain, epilepsy and

migraine). Its use might therefore be expected to

increase significantly in coming years as new indica-

tions for these therapies are established.

Other Implants

Platinum’s biocompatibility makes it ideal for tem-

porary and permanent implantation in the body,

a quality which is exploited in a variety of treatments

in addition to the heart implants already discussed.

Irradiated iridium wire sheathed in platinum can be

implanted into the body to deliver doses of radiation

for cancer therapy (39–41). This treatment takes

advantage of platinum’s radiopacity to shield healthy

tissues from the radiation, while the exposed iridium

tip of the wire irradiates the tumour. Although this

procedure is gradually being replaced by other forms

of radio- and chemotherapy, it remains a useful

weapon in the battle against cancer.

A more recent development is the use of coils

made of platinum wire to treat aneurysms, balloon-

ings in blood vessels caused by weaknesses in the

vessel walls (42).If the blood pressure rises, the vessel

may rupture, causing a haemorrhage. Although this

can occur anywhere in the body, platinum is mainly

used to treat aneurysms in the brain,where surgery is

difficult and fraught with risk. Platinum is used

because it is inert, easy to shape, and radiopaque.

This treatment was first introduced about 20 years

ago. In the late 1980s, a doctor and inventor, Guido

Guglielmi (43–45), developed a detachable platinum

coil which could be used to treat brain aneurysms.

Coils are delivered to the site of the aneurysm by

microcatheter, then detached using an electrolytic

detachment process; once in place, the coils help to

coagulate the blood around the weak vessel wall,



forming a permanent seal (FFiigguurree 44). The coils, num-

bering between one and around thirty depending on

the size of the aneurysm, are left inside the patient

indefinitely. The Guglielmi Detachable Coil (GDC®

Coil) device was approved in Europe in 1992 and in

the USA in 1995, and by 2009 this and subsequent

generations of platinum coil technology were being

used in an estimated 30–40% of US patients treated

for brain aneurysms.

The Manufacture of Platinum

Biomedical Components

There are many technologies used to produce pgm

components for biomedical applications, ranging

from rod, wire, ribbon and tube drawing, to sheet

and foil manufacture and highly precise Swiss-Type

screw machining (micromachining) (see FFiigguurree 55).

Rod and wire are manufactured in diameters

ranging from 0.125" (3.175 mm) down to 0.001"

(0.0254 mm). Dimensional consistency is assured by

laser measurement. Rod is used as the starting material

for a variety of machine components, with most of

the pgm parts being used in pacemaker, defibrillator

and other electrical stimulation products. Wire prod-

ucts are used primarily in three applications:

(a) platinum-tungsten and platinum-nickel fine

wires are used on balloon catheters as guide-

wires for positioning the catheter in exactly the

right location;

(b) other pgm wires are used as microcoils for neu-

rovascular devices such as treatments for brain

aneurysms;

(c) platinum-iridium wires are also used as feed-

through wires or connector wires used to

connect the pacemaker lead to the pulse

generator.

Ribbon is manufactured in the form of continuous

strips of rolled wire in a variety of platinum alloys.

Ribbon is often used in place of round wire to

produce coils with minimum outside diameter,

and is generally used for guidewire and microcoil

applications. Ribbon is sometimes preferred over

wire because wire can be harder to coil. It can also

be used for markers instead of traditional cut tubing.

TTaabbllee IIII shows some typical specifications and

applications for pgm rod, wire and ribbon.

Fine diameter platinum, platinum-iridium and

platinum-tungsten tubing (0.125" (3.175 mm) internal

diameter and below) cut to specific lengths is used

for markers or electrodes on angioplasty, electro-

physiology and neurological catheter devices,

aneurism tip coils, feed-through wires used to con-

nect the pacing lead to the pulse generator (also

known as “the can”) which houses the hybrid micro-

electronics and the battery, and pacemakers. Some

applications of thin walled precious metal tubing

are shown in TTaabbllee IIIIII.



(a) (b) (c)Fig. 4. Detachableplatinum coils being usedto treat an aneurysm:(a) a microcatheter is usedto deliver the platinumcoils to the aneurysm;(b) the coils are detachedusing an electrolyticprocess; (c) more coils areadded to fill the aneurysmand allow blood tocoagulate, forming apermanent seal

Fig. 5. Micromachined parts made from preciousmetal alloys for biomedical device applications, witha pencil tip for scale

Sheet and foil is mainly made from pure platinum,

platinum-iridium alloys or rhodium. It can be shaped,

formed and rolled to a variety of dimensions. Sheet

or foil can be cut, formed and placed on a catheter

for marking in a similar way to ribbon. Rhodium foil

is used exclusively as a filter inside X-ray mammog-

raphy equipment to enhance the viewing image.

TTaabbllee IIVV shows some examples of applications of

pgm sheet and foil.

Micromachined parts are very complex and very

small – some are only 0.006" (0.152 mm) in diameter

and barely visible with the naked eye (FFiigguurree 55).

Fabrication must be extremely precise to maintain

the necessary quality and dimensional tolerances,

which can be as low as ± 0.0002" (0.005 mm). Highly

specialised equipment and techniques must be used,

such as computer numerical controlled (CNC) Swiss

Screw machines and electrical discharge machining

(EDM) (FFiigguurree 66). The automated high-production

Swiss Screw machines are used to fabricate the main

components and EDM is used to achieve the fine

details required for many platinum parts.

Specialty metal micromachined parts (0.8" (20 mm)

diameter and smaller) are made from a variety of

materials including pure platinum, platinum-iridium

alloys and gold plus non-precious metals and



TTaabbllee IIII

SSppeecciiffiiccaattiioonnss aanndd AApppplliiccaattiioonnss ooff PPllaattiinnuumm aanndd PPllaattiinnuumm AAllllooyy RRoodd,, WWiirree aanndd RRiibbbboonn CCoommppoonneennttss

AApppplliiccaattiioonnss TTyyppeess ooff ccoommppoonneenntt SSppeecciiffiiccaattiioonnss

Stimulation devices Rod for manufacture of Diameters from 0.001" (0.0254 mm)

machine components to 0.125" (3.175 mm); Cut lengths

Balloon catheters; stent Guidewires; feed through

delivery; stimulation leads wires; tip coils

TTaabbllee IIIIII

SSppeecciiffiiccaattiioonnss aanndd AApppplliiccaattiioonnss ooff PPllaattiinnuumm,, PPaallllaaddiiuumm,, GGoolldd aanndd PPrreecciioouuss MMeettaall AAllllooyy TThhiinn WWaalllleedd TTuubbee

CCoommppoonneennttss


Balloon catheters Radiopaque marker Inside diameter 0.0045" (0.1143 mm) to 0.250" (6.35 mm),

bands (tolerance: ± 0.0005" (0.0127 mm)); Wall thickness

Electrophysiology Electrode rings

catheters;

stimulation devices

TTaabbllee IIVV

SSppeecciiffiiccaattiioonnss aanndd AApppplliiccaattiioonnss ooff PPllaattiinnuumm,, PPllaattiinnuumm AAllllooyy aanndd RRhhooddiiuumm SShheeeett aanndd FFooiill CCoommppoonneennttss


Stimulation devices Electrodes; machine components; Thickness from 0.0007" (0.018 mm);

tip coils Width from 1.0" (25.4 mm) to

X-Ray equipment Imaging filters (rhodium foils)

from 0.02" (0.508 mm)

0.001" (0.0254 mm) to 0.005" (0.127 mm), (tolerance:

± 0.0005" (0.0127 mm)); Length 0.015" (0.381 mm) to

0.200" (5.08 mm), (tolerance: ± 0.003" (0.0762 mm))

3.75" (95.3 mm)

alloys such as stainless steel, titanium, MP35N®

cobalt-nickel-chromium-molybdenum alloy, Elgiloy®

cobalt-chromium-nickel alloy, Kovar® iron-nickel-

cobalt alloy, and materials such as Vespel®, Delrin®

and Teflon® (see TTaabbllee VV for examples). These prod-

ucts serve device applications such as coronary

stents, pacemaker and defibrillator pulse generator

and lead components, heart valve splices, endoscop-

ic catheters, blood gas analysers, kidney dialysis, and

other medical device and related equipment.

Parts made from pgms are often complemented

with a coating technology. Precious metal powders,



Fig. 6. The production floor at Johnson Matthey’s Medical Products micromachining facility in San Diego,California, USA

TTaabbllee VV

AApppplliiccaattiioonnss aanndd MMaatteerriiaallss ffoorr PPrreecciissiioonn MMiiccrroommaacchhiinneedd CCoommppoonneennttss

AApppplliiccaattiioonnss PPrreecciioouuss mmeettaallss** OOtthheerr mmaatteerriiaallss,, mmeettaallss aanndd aallllooyyss

Stimulation Platinum; platinum alloys; Nitinol; stainless steel; MP35N®;

palladium; palladium alloys Haynes® alloy 25 (L605); polymers

Manufacturing fixtures Platinum; platinum alloys Stainless steel 303/304/316; polymers

Orthopaedic Platinum; platinum alloys Titanium; titanium alloys; stainless steel;

ceramics

Cardiac implants Platinum; platinum alloys; Elgiloy®; Nitinol

karat golds

Hypotubes Platinum; platinum alloys Stainless steel; Nitinol

Precision pins, tips and Platinum; platinum alloys; silver –

rollers

Bushings, shafts, shims Platinum; platinum alloys Aluminium

and spacers

Precision fixtures and Platinum; platinum alloys; BiomedTM Brass; copper; Kovar®

assembly tools series palladium-rhenium alloys

*Platinum alloys used include platinum-iridium, platinum-10% nickel and platinum-8% tungsten

titanium nitride or iridium oxide are applied to

create a more porous surface structure. The creation

of a porous coating reduces the electrical impedance

from the lead to the battery and allows for a good

electrical connection, while reducing the energy

needed to run the battery. This helps the battery to

last longer. Most pacing lead systems manufactured

today have some form of porous surface. The end use

applications for coated pgm parts are the same as

described above for uncoated parts.

Anticancer Drugs

As well as its use in biomedical device components,

perhaps platinum’s most remarkable and unexpected

quality is its ability, in certain chemical forms, to

inhibit the division of living cells (46). The discovery

of this property led to the development of platinum-

based drugs (47), which are now used to treat a wide

range of cancers.

Although cancer remains one of the most feared

diseases, its treatment has advanced rapidly since the

late 1960s. Many types of cancer can now be treated

very effectively using surgery, radiation and drug-

based (chemo-) therapies. Chemotherapy drugs work

by killing cells. They are designed to target cancer

cells as specifically as possible, but inevitably cause

damage to healthy cells as well, causing the side

effects for which chemotherapy is well known.

One of the most remarkable advances in the last

few decades has been the improvement in the sur-

vival rate of patients with testicular cancer – it is esti-

mated that 98% of men with testicular cancer will be

alive 10 years after their diagnosis. The platinum anti-

cancer drug cisplatin (47) has played a vital role in

making testicular cancer one of the most survivable

cancers. This drug, along with its successor drug,

carboplatin (48), is also widely used in the treatment

of other common tumours, including ovarian, breast

and lung cancer.

Summary

For over forty years, platinum and its alloys have been

used in a wide range of medical treatments, includ-

ing devices such as coronary and peripheral

catheters, heart pacemakers and defibrillators. Newer

technologies such as neuromodulation devices and

stents also rely on the biocompatibility, durability,

conductivity and radiopacity of platinum to make key

components in a variety of forms. Platinum is used in

pharmaceutical compounds that extend the lives of

cancer patients. Medical device manufacturers and

pharmaceutical companies continue to invest in new

technologies to satisfy the need for advanced med-

ical treatments in both the developed world and,

increasingly, the developing world. Platinum, the

other pgms and their alloys will inevitably play a vital

part in these developments.

Acknowledgements

The assistance of Richard Seymour and Neil Edwards,

Technology Forecasting and Information, Johnson

Matthey Technology Centre, Sonning Common, UK,

in the preparation of this manuscript is gratefully

acknowledged.

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rances/Recently-ApprovedDevices/ucm082499.htm

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Further Reading “Biomaterials Science: An Introduction to Materials in

Medicine”, 2nd Edn., eds. B. Ratner, A. Hoffman, F. Schoen

and J. Lemons, Elsevier Academic Press, San Diego, CA,

USA, 2004

“Materials and Coatings for Medical Devices: Cardio-

vascular”, ASM International, Materials Park, Ohio,

USA, 2009

Granta: Materials for Medical Devices Database, Cardio-

vascular Materials and Orthopaedic Materials: http://www.

grantadesign.com/products/data/MMD.htm (Accessed on

10th February 2011)

The Authors

Alison Cowley has worked inJohnson Matthey’s Market Researchdepartment since 1990 and currentlyholds the post of Principal Analyst.She is Johnson Matthey’s specialist onmining and supplies of the platinumgroup metals (pgms). She alsoconducts research into demand forpgms in a number of industrialmarkets, including the biomedicaland aerospace sectors.

Brian Woodward has been involved inthe electronic materials and platinumfabrication business for more than25 years and is currently the GeneralManager of Johnson Matthey’s MedicalProducts business based in San Diego,CA, USA. He holds BS and MBAdegrees in Business and Managementand has been focused on value-addedcomponent supply to the globalmedical device industry.



http://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/DeviceApprovalsandClearances/Recently-ApprovedDevices/ucm082499.htm



http://www.grantadesign.com/products/data/MMD.htm

http://www.grantadesign.com/products/data/MMD.htm

Reviewed by Donald S. Cameron

The Interact Consultancy, 11 Tredegar Road,

Reading RG4 8QE, UK;

EE--mmaaiill:: ddccaammeerroonniinntteerraacctt@@aaooll..ccoomm

This was the fifth conference in the Fuel Cells

Science and Technology series following meetings

in Amsterdam, Munich, Turin and Copenhagen (1–4).

It was held on 6th and 7th October 2010 at the World

Trade Center in Zaragoza, Spain, with the theme

‘Scientific Advances in Fuel Cell Systems’. This con-

ference series alternates with the Grove Fuel Cell

Symposium (5), placing more emphasis on the latest

technical developments. The two-day programme

was compiled by the Grove Symposium Steering

Committee from oral papers and posters submitted

from around the world, and the conference was

organised by Elsevier (6). The meeting was attended

by delegates from universities, research organisations

and the fuel cell industry, and as before, many of the

papers will be subjected to peer review and pub-

lished in full in a special edition of Journal of Power

Sources (7).

There were over 200 delegates from 37 countries,

including Spain, Germany and the UK. Although the

majority were from Europe, the significant numbers

from Japan, Iran and South Korea reflected the high

level of interest in fuel cells from those countries, as

well as others from the Middle East, Asia, Africa and

South America.

The Science and Technology conferences present

the latest advances in research and development on

fuel cells and their applications. There were three

plenary papers, together with eight keynote speakers

and 40 oral papers, together with 210 high-quality

poster presentations divided into seven categories.

Topics for the oral sessions included Fuels, Infra-

structure and Fuel Processing; Modelling and Control;

Materials for Fuel Cells; Fuel Cell Systems and

Applications; Fuel Cell Electrochemistry; and finally

Cell and Stack Technology. For this review, only

papers involving the use of the platinum group met-

als (pgms) are discussed.

An exhibition accompanying the conference

included displays of demonstration fuel cell systems

designed for education and training use (FFiigguurreess 11

and 22).

Delegates were welcomed to Zaragoza by Pilar

Molinero, Director General of Energy and Mining for

the Aragon regional government, who formally



Fuel Cells Science and Technology 2010Scientific advances in fuel cell systems highlighted at the semi-annual event






opened the conference and briefly described activi-

ties in Aragon to encourage hydrogen and fuel cell

technologies. The large number of wind farms in the

region have created an interest in energy storage

using water electrolysis to generate hydrogen during

periods of power surplus. A total of 30 hydrogen and

fuel cell projects are being supported, including a

hydrogen highway from Zaragoza to Huesca to sup-

port the introduction of fuel cell vehicles.

Plenary Presentation

Pilar Molinero presented the 2010 Grove Medal to

Professor J. Robert Selman (Illinois Institute of

Technology (IIT), USA), a leading academic who has

devoted more than 30 years to battery and fuel cell

research and development, and to global commer-

cialisation of these technologies. This has included

the electrochemical engineering of batteries and

high temperature fuel cells at the US Department of

Energy’s Argonne National Laboratory and Lawrence

Berkeley National Laboratory, and at the IIT.

Professor Selman presented a talk on his expe-

riences and advances made during this period. One

major development is the advent of computer model-

ling which has led to improved structures and per-

formance of fuel cells and their systems, although

there is still a need to experimentally verify the pre-

dictions obtained at each stage. Other exciting and

relatively new areas include the possibility of direct

carbon oxidation fuel cells, and miniaturisation

including biofuel systems and bioelectrochemistry.

One of his particular interests is the use of phase

change materials to maintain the uniform tempera-

tures in batteries by absorbing or evolving heat.

Fuels, Infrastructure and Fuel Processing

Fuel cell technology has moved on from the largely

research phase to commercial exploitation. A major

market is being developed for combined heat and

power (CHP) systems for residential domestic appli-

cations operating on natural gas. In a keynote pres-

entation, Sascha T. Schröder (National Laboratory for

Sustainable Energy, Technical University of Denmark)

outlined the policy context for micro combined heat

and power (mCHP) systems based on fuel cells.

Systems of up to 50 kW have been considered,

Fig. 1. A 1 kWe polymer electrolyte fuel cell andcontrol equipment designed for teaching purposes,exhibited at the Fuel Cells Science and Technology2010 conference. Operating on pure hydrogen, itcan be used to simulate a wide variety of fuel celland CHP applications. It is built by HELION, anAREVA subsidiary, and developed in collaborationwith teachers from Institut Universitaire deTechnologie (IUT) of Marseille, France

Fig. 2. One of a series of platinum-catalysed fuel celland solar hydrogen systems for educational purposesdesigned and built by Heliocentris. This companydevelops systems and turnkey solutions for trainingin industry and science, and specialises in hybridenergy storage comprising fuel cells, batteries andenergy management devices

although 3–5 kW units are preferred for domestic

installations. Low- and high-temperature polymer

electrolyte membrane (PEM) fuel cells are the most

advanced, although there is still a need for less

expensive reformers to make the systems economi-

cally viable. Incentives in the form of a regulatory

framework and ownership structures are of crucial

importance to achieve widespread use of such

devices in residential applications. A regulatory

review has been conducted as part of the first Work

Package of the EU-sponsored ‘FC4Home’ project,

focused on Denmark, France and Portugal. Schröder

outlined several types of possible support schemes,

such as investment support in the form of capital

grants and tax exemptions versus operating support

in the form of feed-in tariffs, fiscal incentives and

other payments for energy generated, and how this

impacts on investment certainty. Also, the way in

which incentives are offered is critical, for example

via energy service companies, electrical network

operators, natural gas suppliers or network operators

or to individual house owners. Schröder reported that

in Denmark, there are 65 fuel cell mCHP installations,

and in France there are 832, mainly in industry.

Most fuel cells oxidise hydrogen gas using atmos-

pheric air to produce electric power and water.

Hydrogen is generally obtained either by reforming

natural gas or liquid hydrocarbons, or by electrolysis

of water using surplus electrical energy. In recent

years there has been great interest in reforming diesel

fuel both for military and commercial purposes,

since it uses an existing supply infrastructure. The

pgms are often used in reforming reactions and also

in downstream hydrogen purification.

In a talk entitled ‘Experimental and Computational

Investigations of a Compact Steam Reformer for

Fuel Oil and Diesel Fuel’, Melanie Grote (OWI Oel-

Waerme-Institut GmbH, Germany) described the opti-

misation of a compact steam reformer for light fuel

oil and diesel fuel, providing hydrogen for PEM fuel

cells in stationary or mobile auxiliary applications.

Their reformer is based on a catalytically-coated

micro heat exchanger which thermally couples the

reforming reaction with catalytic combustion, and

also generates superheated steam for the reaction

(see FFiigguurree 33). Since the reforming process is sen-

sitive to reaction temperatures and internal flow

patterns, the reformer was modelled using a commer-

cial computational fluid dynamics (CFD) modelling

code in order to optimise its geometry. Fluid flow,

heat transfer and chemical reactions were consid-

ered on both sides of the heat exchanger. The model

was successfully validated with experimental data

from reformer tests with 4 kW, 6 kW and 10 kW ther-

mal inputs of low sulfur light fuel oil and diesel fuel.

In further simulations the model was used to investi-

gate co-flow, counter-flow and cross-flow conditions

along with inlet geometry variations for the reformer.

The experimental results show that the reformer

design used for the validation allows inlet tempera-

tures lower than 500ºC because of its internal super-

heating capability. The simulation results indicate

that another two co-flow configurations provide fast

superheating and high fuel conversion rates. The

temperature increase inside the reactor is influenced

by the inlet geometry on the combustion side. In

current investigations the optimised geometry con-

figurations are being tested in downscaled reformer

prototypes in order to verify the simulation results.

Because of the great detail of their model, the effect

of mass transfer limitations on reactor performance

can now be investigated. Hydrogen of 73% concen-

tration is typically produced.

Successful extraction of hydrogen from heavy

hydrocarbons largely depends on the development

of new catalysts with high thermal stability and

improved resistance to coke formation and sulfur

poisoning. A new range of ruthenium-containing

perovskite oxide catalysts is being examined for

diesel fuel reforming. In a talk entitled ‘Hydrogen Pro-

duction by Oxidative Reforming of Diesel Fuel over

Catalysts Derived from LaCo1−xRuxO3 (x = 0.01–0.4)’,



Fig. 3. Steam reformer with superheater forsupplying hydrogen to a PEM fuel cell(Reprinted from M. Grote et al., (7), withpermission from Elsevier)

Noelia Mota (Instituto de Catálisis y Petroleoquímica

del Consejo Superior de Investigaciones Científicas

(CSIC), Spain) explained how under reforming con-

ditions these LaCo oxides form well-dispersed cobalt

metallic particles over a matrix of lanthana. This

increases hydrogen formation and prevents deactiva-

tion by coke and sulfur. To improve the activity and

stability of LaCoO3-derived catalysts, structural and

electronic modifications can be introduced by

partial substitution of Co by other transition metals,

and among these, ruthenium is a highly effective cat-

alyst. This work studied the influence of the partial

substitution of Co over the physicochemical proper-

ties of LaCo1−xRuxO3 perovskite where x = 0, 0.01,

0.05, 0.1, 0.2 or 0.4 and the effect on the structure

and activity of the derived catalysts in the reforming

of diesel fuel to produce hydrogen. There was an

increase in the rate of hydrogen production associ-

ated with the higher ruthenium content.

Fuel Cell Systems and Applications

The fourteen member countries of the International

Energy Agency Hydrogen Implementing Agreement

(IEA–HIA) have been instrumental in summarising

and disseminating information on integrated fuel cell

and electrolyser systems. In a keynote presentation

entitled ‘Evaluation of Some Hydrogen Demonstra-

tion Projects by IEA Task 18’, Maria Pilar Argumosa

(Instituto Nacional de Técnica Aeroespacial (INTA)

Spain) summarised some of their findings since the

programme was established in 2003. In addition to

establishing a database of demonstration projects

worldwide, the programme has reported in detail on

lessons learned from several demonstrations of

hydrogen distribution systems. The project concen-

trated on fuel cells in the power range 2–15 kW and

exceptionally up to 150 kW. PEM and alkaline elec-

trolysers were studied as hydrogen generators. No

safety incidents occurred during the project,

although the fuel cells tested showed relatively high

performance degradation in field operation. Capital

costs of electrolysers are still high, and maintenance

costs for some systems have ranged up to €15,000 per

year although the warranty protocol was stipu-

lated to be less than €3000 per year for the first

three years. Electrolysers ranged from 50% to 65%

efficiency based on the higher heating value of

the fuel.

Future electrical networks will need active distrib-

uted units able to ensure services like load following,

back-up power, power quality disturbance compen-

sation and peak shaving. In his talk ‘PEM Fuel Cells

Analysis for Grid Connected Applications’, Francesco

Sergi (Consiglio Nazionale delle Ricerche, Italy) out-

lined their investigation of PEM fuel cell systems as

components of power networks. The paper high-

lighted the performances of PEM fuel cells using MEAs

supplied by ETEK containing 30% Pt on Vulcan XC,

and their behaviour during grid connected opera-

tion, particularly the phenomena of materials degra-

dation that can appear in these applications. Several

tests were conducted both on fuel cell systems and

single cells to compare the performances obtained

with DC and AC loads. Power drawn by single phase

grids contains low frequency fluctuations which

cause a large ripple on the stack output current.

During tests on single cells, degradation of the MEA

catalysts has been observed due to these dynamic

loads. A dedicated inverter designed to minimise

the ripple current effect on the fuel cell stack has

enabled durability tests to be performed on a 5 kW

Nuvera PowerFlowTM PEM fuel cell system which

showed no decay in the ohmic region of operation of

the cell after 200 hours, even with the fuel cell sys-

tems operating on the utility grid.

Materials handling using forklift vehicles is proving

to be one of the most exciting early markets for fuel

cells, with over 70 publicly reported demonstration

programmes since 2005 (8). In this application, life-

time and reliability are key parameters. A typical

forklift work cycle is characterised by heavy and fast

variations in power demand, for example additional

power is required during lifting and acceleration.

This is not ideal for a fuel cell and hence it is pre-

ferred to form a hybrid with an energy store. In his

talk ‘Integrated Fuel Cell Hybrid Test Platform in

Electric Forklift’, Henri Karimäki (VTT Technical

Research Centre of Finland) described how a hybrid

power source has been developed for a large coun-

terweight forklift consisting of a pgm-catalysed PEM

fuel cell, ultracapacitors and lead-acid batteries. The

project was carried out in two phases, firstly in the

laboratory with an 8 kW PEM fuel cell, a lead-acid bat-

tery and ultracapacitor to validate the system, then a

second generation 16 kW hybrid system was built into

a forklift truck (FFiigguurree 44). The latter power source

consisted of two 8 kW NedStack platinum-catalysed

PEM fuel cells with two 300 ampere-hour (Ah) lead-

acid batteries and two Maxwell BOOSTCAP® 165F

48V ultracapacitors, providing 72 kW of power.



Hydrogen for the PEM fuel cell is stored on board in

metal hydride canisters connected in common with

the liquid cooling circuit. The energy stores were

connected directly in parallel without intermediate

power electronics to achieve a simple structure and

avoid conversion losses. Drawbacks of this arrange-

ment include limited ultracapacitor utilisation and

lack of direct control over the load profile seen by

the PEM fuel cell. The fuel cell voltage varied from

96 V to 75 V during operation. Control system hard-

ware and software were developed in-house and are

available as open source. The 16 kW system was

tested both in the laboratory with an artificial load

and outdoors installed in a real forklift (Kalmar

ECF556) utilising regenerative braking. After start-up

from warm indoor conditions, outdoor driving tests

were performed in typical southern Finnish winter

weather (−5ºC to −15ºC). The experimental results

allow direct comparison of system performance to

the original lead-acid battery installation.

Many submarines currently under construction are

being fitted with fuel cell power plants and existing

boats are being retrofitted, following pioneering work

by Siemens in Germany and United Technologies

Corporation in the USA. A contract has been awarded

by the Spanish Ministry of Defence to design, develop

and validate an air-independent propulsion (AIP)

system as part of the new S-80 submarine. This pro-

gramme was described by A. F. Mellinas (Navantia SA,

Spain). It is intended that S-80 submarines will exhibit

many performance features currently only available

in nuclear-powered attack boats, including three-

week underwater endurance and the possibility of

firing cruise missiles while submerged. The system is

based on an on-board reformer supplying hydrogen

to a fuel cell power module. Their system will operate

as a submarine battery charger, generating regulated

electrical power to allow long submerged periods.

This application imposes the strictest safety con-

straints while performing under the most demanding

naval requirements including shock, vibration and a

marine environment. It is also intended to combine

high reliability with a minimum acoustic signature to

provide a stealthy performance.

Fuel cell/electrolyser systems are being actively

developed as a means to support astronauts on the

surface of the moon, as explained by Yoshitsugu Sone

(Japan Aerospace Exploration Agency (JAXA)). JAXA

is developing a regenerative fuel cell system that

can be applied to aerospace missions (FFiigguurree 55). For

lunar survival, a large energy store is essential to

allow for the 14 day-14 night lunar cycle. The limited

energy density of the lithium-ion secondary cells

(currently 160–180 Wh kg−1, and likely to be less than

300 Wh kg−1 even in the future) means that over a

tonne of batteries would be needed to last the lunar

night, even for modest power demands.

Initially, PEM fuel cell systems that can be operated

under isolated low-gravity and closed environments

have been studied. Subsystems and operating meth-

ods such as closed gas circulation, with the working

gases in a counter-flow configuration, and a dehydra-

tor were developed to simplify assembly of the fuel

cell system. Fuel cells were combined with electroly-

sers and water separators to form regenerative fuel

cell systems, and the concept has been demonstrated



PEM fuel cells Lead-acidbatteries

Ultra-capacitors

Brakeresistor

Fig. 4. Hybrid forklift powersource with 2 PEM fuel cellstacks (total fuel cell peakpower 16 kW); 2 lead-acidbattery packs (total batterycapacity 24 kWh); 2 ultraca-pacitor modules (capacity~72 kWs assuming 20%utilisation). Hybrid systempeak power in the forklift is~50 kWe (Reprinted from‘Integrated PEMFC HybridTest Platform for IndustrialVehicles’, Fuel Cell Seminar2010, 18th–21st October2010, San Antonio, Texas,USA, by courtesy ofT. Keränen, VTT TechnicalResearch Centre of Finland)

for 1000 hours in an isolated, closed environment.

Practical performance has also been demonstrated,

initially using a thermal vacuum chamber, and also in

a stratospheric balloon in August 2008.

In addition to separate fuel cell stacks and elec-

trolysers, JAXA has developed a regenerative fuel

cell, where the polymer electrolyte fuel cell is com-

bined with the electrolyser to fulfil both functions.

A 100 W-class regenerative fuel cell has been built

and demonstrated as a breadboard model for over

1000 hours. A 17 cell stack of 27 cm2 electrodes pro-

vides an output of 100 W at 12 V, while in the electrol-

ysis mode,‘charging’ is at 28 V.

Fuel Cell Electrochemistry

One of the main challenges facing PEM fuel cells is to

increase the three-phase interface between catalysts,

electrolyte and gases, in order to thrift the amount

of pgm catalyst required. These catalysts are typically

platinum nanoparticles uniformly dispersed on porous

carbon support materials also of nanometre scale. In

her talk entitled ‘Synthesis of New Catalyst Design for

Proton Exchange Membrane Fuel Cell’, Anne-Claire

Ferrandez (Commissariat à l’énergie atomique (CEA)

Le Ripault, France) described grafting polymeric syn-

thon to the surfaces of the platinum nanoparticles,

allowing creation of new architectures of catalyst

layers that promote both ionic conduction between

the solid electrolyte and electronic conduction to the

carbon support. The resulting materials appear to be

oxidation resistant and stable to voltage cycling up

to +1.0 V. By adjusting synthesis parameters, it is

possible to optimise the electrical, chemical and mass

transfer properties of the electrodes and also reduce

the platinum content.

For automotive applications of PEM fuel cells, the

US Department of Energy has published a target

platinum loading of less than 0.2 mg cm−2 for com-

bined anode and cathode by 2015, with performance

characteristics equating to a platinum content of

0.125 g kW−1 by this date (FFiigguurree 66). This is most

likely to be achieved by optimising a combination

of parameters including catalyst, electrode and mem-

brane structures as well as operating conditions. Ben

Millington (University of Birmingham, UK) described

their efforts in a talk entitled ‘The Effect of Fabrication

Methods and Materials on MEA Performance’. Various

methods and materials have been used in the fabri-

cation of catalyst coated substrates (CCSs) for mem-

brane electrode assemblies (MEAs). Different solvents

(ethylene glycol, glycerol, propan-2-ol, tetrahydrofu-

ran and water), Nafion® polymer loadings (up to

1 mg cm−2) and anode/cathode Pt loadings have

been used in the preparation of catalyst inks

deposited onto various gas diffusion layers (GDLs)

sourced from E-TEK, Toray and Freudenberg, and the

performance of the resulting MEAs were reported.

Several methods of CCS fabrication such as painting,

screen printing, decal and ultrasonic spraying were

investigated. All MEAs produced were compared to

both commercial MEAs and gas diffusion electrodes

(GDEs). They found that MEA performance was dra-

matically affected by the solvent type, the deposi-

tion method of the catalyst ink on the GDE, the GDE



Charge

Charge

Charge

Charge

Charge

Discharge

Discharge

Discharge

Discharge

Discharge Discharge

Charge

Electrolyser Fuel cell Unitised regenerative fuel cell

Unitised regenerative fuel cellSeparated type regenerative fuel cell

O2 O2

H2O H2O

H2 H2

Fig. 5. Schematic of the concept for a 100 W regenerative fuel cell system for use in lunarand planetary missions (Reprinted from Y. Sone, (7), with permission from Elsevier)

type (woven or nonwoven), the drying process and

the amount of Nafion® added to the GDE during

fabrication. Currently, the university is able to pro-

duce MEAs with similar performance to commercial

products.

More widespread commercial development of fuel

cells has identified new challenges such as the effects

of impurities in fuel supplies and the atmospheres in

which the devices have to operate. One of these has

been studied in detail at the Technical University of

Denmark, and the results were presented in a paper

by Syed Talat Ali entitled ‘Effect of Chloride Impurities

on the Performance and Durability of PBI

(Polybenzimidazole)-Based High Temperature

PEMFC’. Chlorides derived from sea salt are present in

the atmosphere as an aerosol in coastal areas and salt

is also used for deicing roads in many countries dur-

ing winter. Small traces of chlorides may originate

from phosphoric acid in the PBI membrane and from

platinum chloride precursors used to prepare some

platinum catalysts, while substrate carbons such as

Cabot Vulcan® XC72R carbon black contain trace

impurities. The possible effect of halogen ions on

platinum catalysts are unknown, since they may pro-

mote dissolution as complex ions, thereby enhancing

metal oxidation and re-deposition processes. The

group’s present work is devoted to a systematic study

at temperatures from 25ºC to 180ºC. Firstly, determi-

nation of the chloride content of Pt-based catalysts

was carried out using ion chromatography. Secondly,

the effect of chloride on the dissolution of a smooth

Pt electrode was studied in 85% phosphoric acid at

70ºC using cyclic voltammetry. It was found that the

presence of chlorides is likely to be very harmful to

the long-term durability of acid doped PBI-based

high-temperature PEM fuel cells.

Materials for Fuel Cells

The pgms are also finding applications in hydrogen

generation by water electrolysis as a means of reduc-

ing electrode overvoltage and thereby improving

operating efficiency. This represents not only a clean

method of hydrogen production, but also an efficient

and convenient way of storing surplus energy from

renewable sources such as solar, wind and hydroelec-

tric power. In his talk ‘An Investigation of Iridium

Stabilized Ruthenium Oxide Nanometer Anode

Catalysts for PEMWE’, Xu Wu (Newcastle University,

UK) described the synthesis and characterisation

of these catalysts. The electrochemical activity of

RuxIr1−xO2 materials in the range 0.6 < x < 0.8 was

investigated. A nanocrystalline rutile structure solid

solution of iridium oxide in ruthenium oxide was

identified. When x was 0.8, 0.75, and 0.7, RuxIr1−xO2

exhibited remarkable catalytic activity, while increas-

ing the amount of iridium resulted in improved stabil-

ity. A PEM water electrolysis (PEMWE) single cell

achieved a current density of 1 A cm−2 at 1.608 V with

Ru0.7Ir0.3O2 on the anode, a Pt/C catalyst on the

cathode and Nafion® 117 as the membrane.

Cell and Stack Technology

Considerable progress has been made in develop-

ing high-temperature solid polymer electrolyte

fuel cells, with particular advances in membrane

technology.

In a keynote presentation entitled ‘High Tempera-

ture Operation of a Solid Polymer Electrolyte Fuel Cell

Stack Based on a New Ionomer Membrane’, Antonino

S.Aricó (Consiglio Nazionale delle Ricerche – Istituto

di Tecnologie Avanzate per l’Energia (CNR-ITAE),

Italy) gave details of tests on PEM fuel cell stacks as

part of the European Commission’s Sixth Framework



Fig. 6. Status of estimatedtotal pgm content in fuelcell stacks from 2005 to2009 compared to DOEtargets (J. Spendelow,K. Epping Martin andD. Papageorgopoulos,‘Platinum Group MetalLoading’, DOE HydrogenProgram Record No. 9018,US Department of Energy,Washington, DC, USA,23rd March, 2010)

Programme ‘Autobrane’ project. These were assem-

bled with Johnson Matthey Fuel Cells and SolviCore

MEAs based on the AquivionTM E79-03S short-side

chain (SSC) ionomer membrane, a chemically sta-

bilised perfluorosulfonic acid membrane developed

by Solvay Solexis (FFiigguurree 77). An in-house prepared

catalyst consisting of 50% Pt on Ketjen black was used

for both anode and cathode, applied at 67 wt% cata-

lyst with a Pt loading of 0.3 mg cm–2. Electrochemical

experiments with fuel cell short stacks were performed

under practical automotive operating conditions at

absolute pressures of 1–1.5 bar and temperatures

ranging up to 130ºC, with relative humidity varying

down to 18%. The stacks using large area (360 cm2)

MEAs showed elevated performance in the tempera-

ture range from ambient to 100ºC, with a cell power

density in the range of 600–700 mW cm−2, with a mod-

erate decrease above 100ºC. The performances and

electrical efficiencies achieved at 110ºC (cell power

density of about 400 mW cm−2 at an average cell

voltage of about 0.5–0.6 V) are promising for automo-

tive applications. Duty-cycle and steady-state galvano-

static experiments showed excellent stack stability

for operation at high temperature.

Poster Exhibits

The poster session was combined with an evening

reception to maximise the time available for oral

papers and over 200 posters were offered. These

included a wide range of applications of the pgms in

fuel processing, fuel cell catalysis and sensors. There

were a considerable number of posters featuring the

preparation and uses of pgm fuel cell catalysts, which

were too numerous to mention in detail.

Several posters featured preparation of Pt and PtRu

catalysts supported on carbon nanofibres. It is evi-

dent that while materials such as graphitised carbon

nanofibres can be highly stable and oxidation resist-

ant, with existing catalyst preparation techniques it is

difficult to make high surface area, uniform platinum

dispersions which can compete with catalysts on more

conventional carbon supports such as Vulcan® XC72.

One poster which highlighted this difficulty was

‘Durability of Carbon Nanofiber Supported Electro-

catalysts for Fuel Cells’, by David Sebastián et al.

(Instituto de Carboquímica, CSIC, Spain).

Other posters featured studies of the effects of

carbon monoxide on high-temperature PEM fuel

cells, and the effects of low molecular weight

contaminants on direct methanol fuel cell (DMFC)

performance. Studies are also in progress on more

fundamental aspects such as catalyst/support interac-

tions, for example ‘Investigation of Pt Catalyst/Oxide

Support Interactions’, by Isotta Cerri et al. (Toyota

Motor Europe, Belgium).

Summary

Conclusions from the Fuel Cells Science and Technol-

ogy 2010 conference were summed up by José Luis

García Fierro (Instituto de Catálisis y Petroleoquímica,

CSIC, Spain). He remarked that the high level of inter-

est in the conference partly reflects more strict envi-

ronmental laws combined with the high prices of gas

and oil (oil was US$75 per barrel at the time of the

conference), emphasising the need for the best possi-

ble efficiency in utilising fuels. Biofuels appear to be

making a more limited market penetration than orig-

inally expected. He also mentioned that of the posters

exhibited at the conference, no fewer than 45 involved

PEM fuel cell catalysts and components, direct

methanol and direct ethanol fuel cells. One poten-

tially large market for fuel cells is in shipping, where

marine diesel engines currently produce 4.5% of the

nitrogen oxides (NOx) and 1% of particulates from all

mobile sources. This becomes a sensitive issue, espe-

cially when vessels are in port. The marine market

consists of some 87,000 vessels, the majority of which

have propulsion units of less than 2 MWe. Among the

actions currently in progress to promote exploitation

of hydrogen technology and fuel cells are hydrogen



Fig. 7. Polymer structure of long side-chain Nafion®

and short side chain AquivionTM perfluorosulfonicionomer membranes (Reprinted from A. Stassiet al., (7), with permission from Elsevier)

refuelling stations for vehicles together with codes

and standards for the retail sales of hydrogen fuel,

with support for early market opportunities.

References1 D. S. Cameron, Platinum Metals Rev., 2003, 4477, (1), 28

2 D. S. Cameron, Platinum Metals Rev., 2005, 4499, (1), 16



5 The Grove Fuel Cell Symposium: http://www.grovefuelcell.

com/ (Accessed on 5th January 2011)

6 Fuel Cells Science and Technology: http://www.

fuelcelladvances.com/ (Accessed on 5th January 2011)

7 J. Power Sources, 2011, articles in press

8 V. P. McConnell, Fuel Cells Bull., 2010, (10), 12

The Reviewer

Donald Cameron is an independentconsultant on fuel cells and electrolysers,specialising in electrocatalysis.



http://www.grovefuelcell.com/

http://www.grovefuelcell.com/

http://www.fuelcelladvances.com/

http://www.fuelcelladvances.com/

Reviewed by Judith Kinnaird

School of Geosciences, University of the Witwatersrand,

Private Bag 3, 2050 Wits, South Africa;

EE--mmaaiill:: jjuuddiitthh..kkiinnnnaaiirrdd@@wwiittss..aacc..zzaa

Every few years an International Platinum Symposium

is organised to provide a forum for discussion of

the geology, geochemistry, mineralogy and benefici-

ation of major and minor platinum group element

(PGE) deposits worldwide. The theme of the 11th

International Platinum Symposium, which took place

in Sudbury, Canada, from 21st–24th June 2010 (1),

was “PGE in the 21st Century: Innovations in

Understanding Their Origin and Applications to

Mineral Exploration and Beneficiation”.

Participants from mining and exploration compa-

nies, geological surveys, consulting companies and

universities on all continents attended to listen to

85 papers and read 54 posters. Such meetings nor-

mally take place every four years although it is five

years since the previous meeting in Oulu, Finland in

2005, with a smaller interim meeting held in India.

The organisation was impeccable throughout, for

field trips, poster sessions, the social programme

and the main conference. The committee was led by

Professor C. Michael Lesher (Laurentian University,

Canada), Edward Debicki (Geoscience Laboratories,

Canada), Pedro Jugo (Laurentian University), James

Mungall (University of Toronto, Canada) and Heather

Brown (Ontario Geological Survey, Canada). Sudbury

proved an excellent venue, a mining town that has

developed into a pleasant tree-rich area that has

overcome all the earlier issues of environmental

degradation.

Delegates were told in an overview of the global

pgm industry that the Bushveld Complex in South

Africa and the Norilsk deposit in Russia together

account for roughly 90% of newly mined platinum

and 85% of newly mined palladium supply. The

Stillwater Complex in the USA is a significant source

of palladium but not platinum, while the Great Dyke

in Zimbabwe offers the possibility of significant

expansion (FFiigguurree 11). Russian stockpiles of palladium

are thought to be nearly exhausted, but recycling is

growing rapidly to become another dominant source

of supply. Demand for platinum, palladium and the



11th International PlatinumSymposium “PGE in the 21st Century: Innovations in Understanding Their Origin and Applications toMineral Exploration and Beneficiation”




other pgms is expected to grow strongly, however, and

new deposits of PGEs are of interest as possible

sources of future supply. It is therefore interesting that

the PGEs attract just 2% of overall global exploration

spending, which is focused on Africa, Canada and

Russia.

It was therefore not surprising that several recent

discoveries of deposits of PGEs around the world

were discussed at this meeting, with much progress

made towards understanding their geological origins

and their potential for exploitation as future ore

bodies. Existing deposits were also discussed, but data

on grades were sometimes lacking, and data were

presented as tenors (i.e. the grade calculated in 100%

sulfide only). Other studies focused on experimental

measurements, analytical techniques and results,

new geochemical criteria for the identification of

PGE-enriched deposits, characterisation of platinum

group mineral assemblages and the processes that

extract platinum from ore.

Papers of particular interest have been collated

and summarised below, according to geographical

region. All abstracts are available on the conference

website (1). It is important to note that there are six

platinum group elements (PGEs): platinum, palla-

dium, rhodium, iridium, osmium and ruthenium.

Geologists use the term ‘PGM’ to mean platinum

group minerals as the PGEs occur in minerals rather

than metallic form in natural deposits, whereas metal-

lurgists use ‘pgm’ to mean platinum group metals.



Snake’s Head

Zambesi Mobile Belt

Ngezi

Unki

Mimosa

Hartley PlatinumSSoo

uutthh

CChhaamm

bbeerr

Mhondoro and Zinca

MusengeziSubchamber

Harare

Selous

Bulawayo

Harare

Zimbabwe

craton

200 km

km

0 50 100

NNoorrtt

hh CC

hhaamm

bbeerr

East

Dyk

e

East

Dyk

e

North M

arginal Zone

of the Lim

popo Belt

South

ern

sate

llite

sW

edza

Subch

amber

Selu

kwe

Subch

amber

Sebak

we

Subch

amber

Dar

wen

dal

eSu

bch

amber

Mafic sequence

Ultramafic sequence

Satellite dykes

Craton & cover rocks

Mobile belts

Major faults & fractures

29ºE 31ºE

19ºS

18ºS

16ºS

17ºS

Fig. 1. Large-scale map ofthe Great Dyke inZimbabwe, showing majorlithological subdivisionsand areas of currentexploitation. The GreatDyke is the largest resourceof platinum outside theBushveld Complex ofSouth Africa. Its size hasencouraged activeexploration and mining,and in 2010 there werethree major mines inoperation and severalintensive explorationinitiatives (Courtesy ofA. H. Wilson andA. J. du Toit, from ‘GreatDyke Platinum in the Regionof Ngezi Mine, Zimbabwe:Characteristics of the MainSulphide Zone andVariations that AffectMining’, 11th InternationalPlatinum Symposium,Sudbury, Ontario, Canada,21st–24th June, 2010)

Southern Africa

The opening day of the symposium focused on South

Africa’s Bushveld Complex and Zimbabwe’s Great

Dyke, as is fitting for the largest producers of platinum.

For the Bushveld, chromitite layers were described

from at least six cyclic units of ultramafic Lower Zone

in the northeastern limb, that have previously been

regarded as Marginal Zone but no platinum grades

were given. Profiles of PGEs through chromitites in

the layered mafic-ultramafic suite showed that plat-

inum per unit metre through the complex was highest

in the north west.The atypical stratigraphic sequence

of the ‘contact-type’ basal nickel-copper-PGE mineral-

isation of the satellite Sheba’s Ridge at the western

extremity of the eastern limb is unique with discontin-

uous UG2 Reef and Merensky Reef analogues above

a basal ‘Platreef’-style sulfide-rich ore body with

grades of <2 parts per million (ppm) Pt and <2.5 ppm

Pd and a Pt:Pd ratio typically ∼0.5, in contrast to the

UG2 and Merensky Reefs of the western and eastern

limbs where platinum exceeds palladium.This ratio is

similar to that for the composite Platreef of the north-

ern limb, which is up to 500 m thick. The Platreef also

does not correlate closely with the Merensky Reef

although the Platreef was shown to be the same age.

In the Great Dyke of Zimbabwe, PGEs are con-

tained in the stratiform Main Sulphide Zone near the

top of the ultramafic succession. In this zone there is

a consistent pattern of a lower Pd-enriched subzone

(Pt:Pd ratio of 0.7:1) with Pd <2 ppm and an upper

Pt-enriched subzone (Pt:Pd ratio of 2.5:1) with values

of Pt up to 4 ppm, which are separated by a narrow

transition zone.

North America and Canada

The Midcontinent Rift in North America, which has

been known for its undeveloped low-grade dissemi-

nated deposits, may become the next major Cu-Ni-

PGE mining district as several new, higher-grade dis-

coveries have been made which together have in situ

metal values over US$325 billion. The bulk of these

resources have been discovered in or near the

Duluth Complex in northeastern Minnesota, USA,

and include the following:

• The Nokomis deposit: a large, PGE-rich dissemi-

nated sulfide deposit with a reported estimate of

5 million ounces of Pt and nearly 10 million

ounces of Pd;

• The Current Lake Complex near Thunder Bay

in Ontario, Canada: a Pt-rich disseminated to

net-textured sulfide deposit. Disseminated Cu-Ni-

Pt-Pd sulfide mineralisation is hosted within a

tubular to tabular magma conduit with local high

grade zones (4.5 ppm Pt, 4.3 ppm Pd, 1.0% Cu

and 0.6% Ni) and 14 m of higher-grade net-

textured and massive sulfide near the base of the

intrusion which averages 16.2 ppm Pt, 13.9 ppm

Pd, 3.5% Cu and 1.2% Ni;

• The Eagle deposit in Michigan: a high-grade mas-

sive to net-textured ore body with a reported

resource estimated at 4.05 megatonnes (Mt) at

an average grade of 0.73 ppm Pt, 0.47 ppm Pd,

2.9% Cu and 3.57% Ni;

• The Tamarack deposit in Minnesota: similarly a

high-grade massive to net-textured ore body.

All these deposits have higher Pt:Pd ratios (com-

monly ≥1:1) than the ‘typical’ Duluth Complex dis-

seminated deposits (where ratios are typically ≤1:2).

Such discoveries, which are regarded as analogous to

Norilsk in Russia, have led to significant exploration

in the region for similar conduit-style ores.

In ancient Archaean rocks of northern Ontario, the

recently discovered Eagle’s Nest Ni-Cu-PGE minerali-

sation is interpreted as a feeder conduit beneath an

extensive complex of sills and related volcanic rocks

with pools of massive sulfide at or near the lower con-

tact. The Archaean Blackbird chromite-bearing sill

found in the James Bay Lowlands in 2008 is a sill-

hosted chromite deposit analogous to the Kemi

deposit in Finland. The chromitites have no sulfides,

and PGE grades are low.

Canada’s East Bull Lake intrusive suite hosts sever-

al contact-style Cu-Ni-PGE occurrences within several

of the larger intrusions, most notably in the River

Valley area. Grades of up to 25 parts per billion (ppb)

Pt and 33 ppb Pd were described for some of the

intrusions.

The West Raglan Ni-Cu-PGE project, in the early

Proterozoic Cape Smith Fold Belt of northern

Quebec, hosts several economic Ni-Cu-PGE sulfide

deposits (such as Xstrata’s Raglan deposits) and sev-

eral more recent discoveries (Goldbrook Ventures’

Mystery prospect and Canadian Royalties’ Mesamax

deposit, for example). Nickel sulfide deposits are

spatially associated with mafic-ultramafic sills and

intrusive complexes. Since 2003, drilling of the

Raglan trend has identified several discrete miner-

alised lenses at West Raglan which include a 36.43 m

interval at a grade of 2.54 ppm PGEs, 1.1% Cu and

2.66% Ni.



The PGE deposits of the Lac des Iles Complex in

Canada (the Roby, Twilight and High-Grade Zones)

differ from most other PGE deposits as they occur in

a small, concentrically-zoned mafic intrusion rather

than in a large layered intrusion and the ore zone is

∼900 m by 700 m in size and open at depth rather

than thin and tabular. Pentlandite controls 30% of

whole-rock palladium, the rest is present as PGMs.

In spite of more than a century of mining in the

Sudbury district of Canada, new discoveries are still

being made. The principal styles of Cu-Ni sulfide

mineralisation that have been mined are:

(a) in the Sublayer at the lower contact of the

Sudbury Igneous Complex;

(b) in quartz diorite Offset Dykes (with grades of <10

ppm Pt and <10 ppm Pd); and

(c) the Frood-Stobie Breccia Belt.

However, in the past 20 years, there has been a pro-

gressive shift towards mining footwall deposits that

are enriched in Cu, Ni and PGEs. The recently recog-

nised ‘low-sulfide’ Cu-Ni-PGE systems represent the

most Pt- and Pd-enriched mineralisation type within

the footwall in the North and East Ranges of the 1.85

Ga complex (FFiigguurree 22((aa))). When present, mineralisa-

tion is generally peripheral to footwall deposits and

can also occur in the footwall immediately adjacent

to Cu-rich portions of the offset ore bodies. The

newly-discovered Capre 3000 mineralised zone in the

East Range has PGE abundances similar to other

North Range footwall vein-style systems. These are

associated with sulfides at a brecciated contact

between granite and gneiss. In the South Range, the

109 FW Zone low-sulfide deposit is a new discovery

in the footwall of the Crean Hill Mine adjacent to a

previously exploited contact sulfide deposit (FFiigguurree

22((bb))).

Russia and Northern Finland

The Kemi intrusion in northern Finland hosts the

largest economic chrome deposits outside the

Bushveld Complex but PGEs are low in abundance,

with a maximum combined Pt and Pd grade of <50

ppb and typical grades ranging between about 20–30

ppb in the lower half and <10 ppb in the upper half

of the intrusion. By contrast, the Kievey ore body in

the Fedorovo-Pansky layered mafic intrusion of the

Kola Peninsula in Russia has a combined Pt, Pd

and Au grade varying from 0.8 ppm to 18.2 ppm

(Pd:Pt = 6.7) with an average Cu grade of 0.15% and

Ni grade of 0.13%.

New information on the geology and PGE mineral-

isation of two other intrusions of the Kola region was

presented. The Volchetundra layered mafic intrusion

is 40 km long and 2–4 km wide, with marginal and

irregular sulfide-rich lenses in the steeply-dipping

eastern contact zone. These are up to 30 m thick with

PGE grades ranging from 0.1–3.7 ppm (typically

0.1–0.3 ppm) and Pd:Pt ratios from 2–5, although

sulfide-rich pods with higher-grade (up to 5 ppm)

PGEs have been delineated. In addition, reef-type

mineralisation in layered gabbro-gabbronorite of the

Main Zone is 1–18 m thick, with low to no sulfides,

PGE grades from 2–20 ppm and Pd:Pt ratios of 0.4–1.

The lenticular shaped Monchatundra layered intru-

sion extends over almost 500 km2 and ranges in com-

position from dunite to anorthosite. The ‘Frequently

Interlayered Zone’ within the mafic-ultramafic part

of the intrusion has disseminated sulfides (usually

0.5–2%, but locally up to 30%) and PGE mineralisa-

tion. The zone varies up to 130 m in thickness but

the ore-bearing interval ranges from 0.3 m to 42 m,

typically between 3 m and 18 m. The PGE grade

varies between 1.5–3.5 ppm with Pd:Pt ratios of 1.5–3.

Several papers reviewed aspects of the world class

Cu-Ni-PGE deposits of the Norilsk mafic-ultramafic

intrusions in Siberia. All important resources are

concentrated in three intrusions: the Talnakh,

Kharaelakh, and Norilsk 1 (Krivolutskaya) massifs.

The newly-discovered Cu-Ni-PGE Maslovskoe deposit

in the north of the Norilsk Trough comprises a

Northern intrusion which is very similar to the

Norilsk 1 massif and may be a southwest branch, and

a separate Southern Maslovsky intrusion. Both massifs

contain disseminated ores and veins and belong to

the Norilsk Intrusive Complex.The veinlet-disseminat-

ed ores of the Northern Maslovskoe deposit are

enriched in up to 25 ppm PGEs.

China

The Jinchuan nickel-copper deposit is the third largest

magmatic sulfide deposit in the world. It occurs in a

small, dyke-like ultramafic intrusion (6500 m × 400 m ×1100 m) in the western margin of the Northern China

Craton. Mineralisation is disseminated, net textured

or massive according to sulfide content. PGE abun-

dances are given in TTaabbllee II.

Brazil

Several favourable settings for Ni-Cu-PGE deposits

in Brazil include numerous large layered intrusions





Massive sulfide

Low sulfide PGE-Au

Disseminated Ni sulfide

Undifferentiated gneiss

Granite breccia

Sudbury breccia

Sudbury igneous complex

Diabase

Granite

Fault m

0 250

AA

DD

BB

CC

AABBCCDD

Contact

Footwall type

Low sulfide

Capre footwall

New discovery

(a)

(b)

Inclusion massive/

breccia sulfide

Siliceous zone

Disseminated Ni-Cu sulfide

Low sulfide, high PGE

mineralisation

Metasediments

Metavolcanic

Sudbury breccia

Granite

Quartz diorite

Norite

Trap dyke

Shear zone

Surface

Surface

DD

BB

AACC

AABBCCDD

Contact

Footwall type

Breccia belt type

109 FW

New discovery

0 100

Fig. 2. Composite cross-sections of typical geological settings for Footwall Deposits of PGEs and sulfidein the Sudbury Igneous Complex, Canada, in (a) the North and East Range and (b) the South Range (Courtesyof P. C. Lightfoot and M. C. Stewart, from ‘Diversity in Platinum Group Element (PGE) Mineralization atSudbury: New Discoveries and Process Controls’, 11th International Platinum Symposium, Sudbury, Ontario,Canada, 21st–24th June, 2010)

in cratonic areas, several clusters or lineaments

of mafic and mafic-ultramafic intrusions where

feeder dykes and the lowermost parts of layered

intrusions are exposed, a continental-scale province

of flood basalts, and several areas of extensive komati-

itic magmatism in Precambrian greenstone belts.

The Fortaleza de Minas komatiite-hosted Ni-Cu

deposit is quoted as an estimated resource of 6 Mt at

grades of 0.7 ppm combined Pt, Pd and Au, 0.4% Cu

and 2.5% Ni. The layered mafic-ultramafic lithologies

of the Tróia Unit of the Cruzeta Complex in north-

eastern Brazil have been the focus of platinum explo-

ration for more than 30 years. Local chromitite

horizons, 0.3 m to 3 m thick, contain up to 8 ppm Pt

and 21 ppm Pd.

Other Occurrences

Komatiite-hosted Ni-Cu deposits with PGEs from

Australia and Canada were discussed. PGE-bearing

chromitites from eastern Cuba and elsewhere were

described. Data from the Al’Ays ophiolite complex in

Saudi Arabia have shown that podiform chromitites

with high PGE concentrations (above 1.4 ppm) also

have distinctive minor element concentrations that

provide an improved fingerprint for further explo-

ration. The Ambae chromites of the Vanuatu Arc in

the south-west Pacific have grades of 75.8 ppb Rh,

52.1 ppb Ir, 36.8 ppb Os and 92.6 ppb Ru, whereas

Pd, Pt and Au are below the detection limit. These

values account for 56% of the Ir, over 90% of the

Ru and 22% of the Rh present in the Ambae lavas.

Reconnaissance studies of the PGEs potential of four

chromite mining districts in southern Iran showed

that chromites have concentrations of 6 PGEs (com-

bined Pt, Pd, Rh, Ir, Os and Ru) from 57 ppb to

5183 ppb with an average of 456 ppb.

New Discoveries

New Cu-Au-PGE mineralisation was reported from the

Togeda macrodyke in the Kangerlussuaq region of

East Greenland. A metasediment-hosted deposit from

Craignure, Inverary, in Scotland hosts sulfide mineral-

isation with PGE concentrations locally exceeding

3 ppm and, although small, this raises the possibility

of other metasediment-hosted Ni-Cu-PGE mineralisa-

tion in Scotland. Amphibolites and their weathered

equivalents on the northwest border of the Congo

Craton in South Cameroon have a PGEs plus Au con-

tent of 53 ppb to 121 ppb. The Pd:Pt ratios are ∼ 3.

Ni-Cu-PGE mineralisation was described from the

Gondpipri area of central India but Ni and Cu domi-

nate and PGE content is low.

Process Mineralogy in the Platinum

Industry and Future Trends

This was perhaps a new topic for these events.

Laser ablation inductively coupled plasma mass

spectrometry (LA-ICP-MS) mapping provides critical

information on the distribution of the PGEs in and

around magmatic sulfides and is useful in charac-

terising PGE deposits. As an example of the insights

that can be gained with this technique, new data

for samples from the Merensky Reef and Norilsk-

Talnakh show that the behaviour of Pt is very differ-

ent from that of Pd and Rh, which are generally

hosted by pentlandite. Pt often forms a plethora of

discrete phases in association with the trace and

semi-metals. The variable distribution of these phases

has implications for geometallurgical models and

PGE recoveries.

While the PGEs are most often concentrated in

sulfide minerals such as pyrrhotite, pentlandite and

chalcopyrite, there were several reports at the



TTaabbllee II

PPllaattiinnuumm GGrroouupp EElleemmeenntt AAbbuunnddaanncceess ooff tthhee JJiinncchhuuaann DDeeppoossiitt iinn CChhiinnaa

OOrree ttyyppee PPllaattiinnuumm PPaallllaaddiiuumm RRhhooddiiuumm IIrriiddiiuumm RRuutthheenniiuumm

ggrraaddee,, ppppbb ggrraaddee,, ppppbb ggrraaddee,, ppppbb ggrraaddee,, ppppbb ggrraaddee,, ppppbb

Disseminated 35.8–853 74.8–213 2.5–19.5 5.1–38.5 4.2–33.1

Net-textured 12.7–1757a 171–560 0.7–5.1 0.4–4.0 1.5–3.5

Massive 11.6–102 218–1215 78.1–201 211–644 91–553

aOne exceptional occurrence of 3343 ppb


symposium of pyrite hosting appreciable amounts of

Rh and Pt. Pyrite from the McCreedy and Creighton

deposits of Sudbury has a similar Os, Ir, Ru, Re

(rhenium) and Se (selenium) content to that of coex-

isting pyrrhotite and pentlandite, whereas Rh (at up

to 130 ppm), arsenic (up to 30 ppm), Pt and Au show

a stronger preference for pyrite than for pyrrhotite or

pentlandite. In the Canadian Cordilleran porphyry

copper systems, up to 90% of the Pd and Pt in miner-

alised samples occurs in pyrite.

Concluding Remarks

With reports of a number of new discoveries along-

side much new information on existing resources,

the 11th International Platinum Symposium pro-

vided the industry with the most comprehensive

overview yet of platinum group element deposits

worldwide. While many of these deposits have rela-

tively low grades of PGEs, they may still prove to be

viable and valuable sources of pgms in the future.

Exploration efforts are also expected to become more

efficient as a greater understanding of the geological

process behind the formation of PGE deposits is

gained.

Reference1 The 11th International Platinum Symposium at Laurentian

University: http://11ips.laurentian.ca/Laurentian/Home/

Departments/Earth+Sciences/NewsEvents/11IPS/ (Accessed

on 7th January 2011)

The Reviewer

Judith Kinnaird is a Professor ofEconomic Geology at the School ofGeosciences at the University of theWitwatersrand, South Africa, andDeputy Director of the University’sEconomic Geology Research Institute(EGRI). Her research interests includeBushveld Complex magmatism andmineralisation especially of thePlatreef in the northern limb, whileher research team is currentlyconducting studies on chromititegeochemistry, mineralogy and PGEgrade distribution; tenor variations;zircon age-dating; Lower Zonemineralogy and geochemistry of theBushveld Complex in South Africa.


http://11ips.laurentian.ca/Laurentian/Home/Departments/Earth+Sciences/NewsEvents/11IPS/

http://11ips.laurentian.ca/Laurentian/Home/Departments/Earth+Sciences/NewsEvents/11IPS/

By John W. Arblaster

Wombourne, West Midlands, UK;


This is the fifth in a series of reviews on the circum-

stances surrounding the discoveries of the isotopes

of the six platinum group elements. The first review

on platinum isotopes was published in this Journal

in October 2000 (1), the second on iridium isotopes in

October 2003 (2), the third on osmium isotopes in

October 2004 (3) and the fourth on palladium isotopes

in April 2006 (4).

Naturally Occurring RhodiumIn 1934, at the University of Cambridge’s Cavendish

Laboratory, Aston (5) showed by using a mass spec-

trograph that rhodium appeared to consist of a single

nuclide of mass 103 (103Rh). Two years later Sampson

and Bleakney (6) at Princeton University, New Jersey,

using a similar instrument, suggested the presence of

a further isotope of mass 101 (101Rh) with an abun-

dance of 0.08%. Since this isotope had not been dis-

covered at that time, its existence in nature could not

be discounted. Then in 1943 Cohen (7) at the

University of Minnesota used an improved mass spec-

trograph to show that the abundance of 101Rh must be

less than 0.001%. Finally in 1963 Leipziger (8) at the

Sperry Rand Research Center, Sudbury, Massachusetts,

used an extremely sensitive double-focusing mass

spectrograph to reduce any possible abundance to

less than 0.0001%. However by that time 101Rh had

been discovered (see Table I) and although shown to

be radioactive, no evidence was obtained for a long-

lived isomer. This demonstrated conclusively that

rhodium does in fact exist in nature as a single

nuclide: 103Rh.

Artificial Rhodium IsotopesIn 1934, using slow neutron bombardment, Fermi

et al. (9) identified two rhodium activities with half-

lives of 50 seconds and 5 minutes. A year later the

same group (10) refined these half-lives to 44 seconds

and 3.9 minutes. These discoveries were said to be

‘non-specific’ since the mass numbers were not



The Discoverers of the RhodiumIsotopesThe thirty-eight known rhodium isotopes found between 1934 and 2010


determined, although later measurements identified

these activities to be the ground state and isomeric

state of 104Rh, respectively. In 1940 Nishina et al.

(11, 12), using fast neutron bombardment, identified

a 34 hour non-specific activity which was later identi-

fied as 105Rh. In 1949 Eggen and Pool (13) confirmed

the already known nuclide 101Pd and identified the

existence of a 4.7 day half-life rhodium daughter

product. They did not comment on its mass although

the half-life is consistent with the isomeric state of101

Rh. Eggen and Pool also identified a 5 hour half-life

activity which was never subsequently confirmed.

Activities with half-lives of 4 minutes and 1.1 hours,

obtained by fast neutron bombardment, were identi-

fied by Pool, Cork and Thornton (14) in 1937 but

these also were never confirmed.

Although some of these measured activities repre-

sent the first observations of specific nuclides, the

exact nuclide mass numbers were not determined

and therefore they are not considered to represent

actual discoveries. They are however included in

the notes to Table I. The first unambiguous identifi-

cation of a radioactive rhodium isotope was by

Crittenden in 1939 (15) who correctly identified

both 104Rh and its principal isomer. Nuclides where

only the atomic number and atomic mass number

were identified are considered as satisfying the dis-

covery criteria.

Discovery DatesThe actual year of discovery is generally considered

to be that when the details of the discovery were

placed in the public domain, such as manuscript

dates or conference report dates. However, complica-

tions arise with internal reports which may not be

placed in the public domain until several years after

the discovery, and in these cases it is considered that

the historical date takes precedence over the public

domain date. Certain rhodium isotopes were discov-

ered during the highly secretive Plutonium Project of

the Second World War, the results of which were not

actually published until 1951 (16) although much of

the information was made available in 1946 by Siegel

(17, 18) and in the 1948 “Table of Isotopes”(19).

Half-LivesSelected half-lives used in Table I are generally those

accepted in the revised NUBASE evaluation of

nuclear and decay properties in 2003 (20) although

literature values are used when the NUBASE data are

not available or where they have been superseded by

later determinations.



Table I

The Discoverers of the Rhodium Isotopes

Mass numberaa Half-llife Decay Year of Discoverers References Notesmodes discovery

89 psb EC + β+ ? 1994 Rykaczewski et al. 21, 22

90 15 ms EC + β+ 1994 Hencheck et al. 23 A

90m 1.1 s EC + β+ 2000 Stolz et al. 24 A

91 1.5 s EC + β+ 1994 Hencheck et al. 23 B

91m 1.5 s IT 2004 Dean et al. 25 B

92 4.7 s EC + β+ 1994 Hencheck et al. 23 C

92m 0.5 s IT? 2004 Dean et al. 25 C

93 11.9 s EC + β+ 1994 Hencheck et al. 23 D

94 70.6 s EC + β+ 1973 Weiffenbach, Gujrathi and Lee 26

94m 25.8 s EC + β+ 1973 Weiffenbach, Gujrathi and Lee 26

95 5.02 min EC + β+ 1966 Aten and Kapteyn 27

95m 1.96 min IT, EC + β+ 1974 Weiffenbach, Gujrathi and Lee 28

Continued



Table I

The Discoverers of the Rhodium Isotopes (Continued)


96 9.90 min EC + β+ 1966 Aten and Kapteyn 27

96m 1.51 min IT, EC + β+ 1966 Aten and Kapteyn 27

97 30.7 min EC + β+ 1955 Aten and de Vries-Hamerling 29

97m 46.2 min EC + β+, IT 1971 Lopez, Prestwich and Arad 30

98 8.7 min EC + β+ 1955 Aten and de Vries-Hamerling 29 E

98m 3.6 min EC + β+ 1966 Aten and Kapteyn 31

99 16.1 d EC + β+ 1956 Hisatake, Jones and Kurbatov 32 F

99m 4.7 h EC + β+ 1952 Scoville, Fultz and Pool 33

100 20.8 h EC + β+ 1944 Sullivan, Sleight and Gladrow 34, 35 G

100m 4.6 min IT, EC + β+ 1973 Sieniawski 36

101 3.3 y EC 1956 Hisatake, Jones and Kurbatov 32 F

101m 4.34 d EC, IT 1944 Sullivan, Sleight and Gladrow 34, 37 G

102 207.0 d EC + β+, β− 1941 Minakawa 38

102m 3.742 y EC + β+, IT 1962 Born et al. 39

103 Stable – 1934 Aston 5

103m 56.114 min IT 1943 (a) Glendenin and Steinberg (a) 40, 41 H

(b) Flammersfeld (b) 42

104 42.3 s β− 1939 Crittenden 15 I

104m 4.34 min IT, β− 1939 Crittenden 15 I

105 35.36 h β− 1944 (a) Sullivan, Sleight and Gladrow (a) 34, 43 J

(b) Bohr and Hole (b) 44

105m 42.9 s IT 1950 Duffield and Langer 45

106 30.1 s β− 1943 (a) Glendenin and Steinberg (a) 40, 41 K

(b) Grummitt and Wilkinson (b) 46

(c) Seelmann-Eggebert (c) 47

106m 2.18 h β− 1955 Baró, Seelmann-Eggebert 48 L

and Zabala

107 21.7 min β− 1954 (a) Nervik and Seaborg (a) 49 M

(b) Baró, Rey and (b) 50

Seelmann-Eggebert

108 16.8 s β− 1955 Baró, Rey and 50 N

Seelmann-Eggebert

108m 6.0 min β− 1969 Pinston, Schussler and Moussa 51

Continued



Table I

The Discoverers of the Rhodium Isotopes (Continued)


109 1.33 min β− 1969 Wilhelmy et al. 52, 53

110 28.5 s β− 1969 (a) Pinston and Schussler (a) 54

(b) Ward et al. (b) 55

110m 3.2 s β− 1963 Karras and Kantele 56

111 11 s β− 1975 Franz and Herrmann 57

112 3.4 s β− 1969 Wilhelmy et al. 52, 53

112m 6.73 s β− 1987 Äystö et al. 58

113 2.80 s β− 1988 Penttilä et al. 59

114 1.85 s β− 1969 Wilhelmy et al. 52, 53

114m 1.85 s β− 1987 Äystö et al. 58

115 990 ms β− 1987 Äystö et al. 60, 61

116 680 ms β− 1987 Äystö et al. 58, 60, 61

116m 570 ms β− 1987 Äystö et al. 58, 60, 61

117 394 ms β− 1991 Penttilä et al. 62

118 266 ms β− 1994 Bernas et al. 63 O

119 171 ms β− 1994 Bernas et al. 63 P

120 136 ms β− 1994 Bernas et al. 63 Q

121 151 ms β− 1994 Bernas et al. 63 P

122 psb β− ? 1997 Bernas et al. 64

123 psb β− ? 2010 Ohnishi et al. 65 See Figures 1

and 2


and 2


and 2


and 2

am = isomeric state bps = particle stable (resistant to proton and neutron decay)



Fig. 1. The superconducting ring cyclotron (SRC) in the Radioactive Isotope Beam Factory (RIBF) at theRIKEN Nishina Center for Accelerator-Based Science where the newest isotopes of palladium, rhodiumand ruthenium were discovered (65) (Copyright 2010 RIKEN)

Dr Toshiyuki Kubo

Toshiyuki Kubo is the team leader of the Research Group at RIKEN.

He was born in Tochigi, Japan, in 1956. He received his BS degree

in Physics from The University of Tokyo in 1978, and his PhD

degree from the Tokyo Institute of Technology in 1985. He joined

RIKEN as an Assistant Research Scientist in 1980, and was promot-

ed to Research Scientist in 1985 and to Senior Research Scientist

in 1992. He spent time at the National Superconducting Cyclotron

Laboratory of Michigan State University in the USA as a visiting

physicist from 1992 to 1994. In 2001, he became the team leader for

the in-flight separator, dubbed ‘BigRIPS’, which analyses the frag-

ments produced in the RIBF. He was promoted to Group Director

of the Research Instruments Group at the RIKEN Nishina Center in

2007. He is in charge of the design, construction, development and

operation of major research instruments, as well as related infra-

structure and equipment, at the RIKEN Nishina Center. His current

research focuses on the production of rare isotope beams, in-flight

separator issues, and the structure and reactions of exotic nuclei.

Fig. 2. Dr Toshiyuki Kubo(Copyright 2010 RIKEN)



Notes to Table I

A 90Rh and 90mRh Hencheck et al. (23) only proved that the isotope was particle stable. Stolz et al.

(24) in 2000 identified both the ground state and an isomer. The half-life deter-

mined by Wefers et al. in 1999 (66) appears to be consistent with the ground

state. The discovery by Hencheck et al. is nominally assigned to the ground state.

B 91Rh and 91mRh Hencheck et al. (23) only proved that the isotope was particle stable. Wefers et al.

(66) first determined a half-life in 1999 but Dean et al. (25) remeasured the half-

life in 2004 and identified both a ground state and an isomer having identical

half-lives within experimental limits. The discovery by Hencheck et al. is nominally

assigned to the ground state.

C 92Rh and 92mRh Hencheck et al. (23) only proved that the isotope was particle stable. Wefers et al.

(66) incorrectly determined the half-life in 1999 with more accurate values being

determined by both Górska et al. (67) and Stolz et al. (24) in 2000. Dean et al.

(25) showed that these determinations were for the ground state and not for the

isomeric state which they also identified. The discovery by Hencheck et al. is nomi-

nally assigned to the ground state.

D 93Rh Hencheck et al. (23) only proved that the isotope was particle stable. Wefers et al.

in (66) incorrectly measured the half-life in 1999 with more accurate values being

obtained by both Górska et al. (67) and Stolz et al. (24) in 2000.

E 98Rh Aten et al. (68) observed this isotope in 1952 but could not decide if it was96Rh or 98Rh.

F 99Rh and 101Rh Farmer (69) identified both of these isotopes in 1955 but could not assign mass

numbers.

G 100Rh and 101mRh For these isotopes the 1944 discovery by Sullivan, Sleight and Gladrow (34) was

not made public until its inclusion in the 1948 “Table of Isotopes” (19).

H 103mRh Although both Glendenin and Steinberg (40) and Flammersfeld (42) discovered

the isomer in 1943 the results of Glendenin and Steinberg were not made public

until their inclusion in the 1946 table compiled by Siegel (17, 18).

I 104Rh and 104mRh Both the ground state and isomer were first observed by Fermi et al. (9) in 1934

and by Amaldi et al. (10) in 1935 as non-specific activities. Pontecorvo (70, 71)

discussed these activities in detail but assigned them to 105Rh. EC + β+ was also

detected as a rare decay mode (0.45% of all decays) in 104Rh by Frevert,

Schöneberg and Flammersfeld (72) in 1965.

J 105Rh For this isotope the 1944 discovery by Sullivan, Sleight and Gladrow (34) was not

made public until its inclusion in the 1946 table of Siegel (17, 18). The isotope

was first identified by Nishina et al. (11, 12) in 1940 as a non-specific activity.

K 106Rh The discovery by Glendenin and Steinberg (40) in 1943 was not made public until

Continued



Some of the Terms Used for This Review

Atomic number The number of protons in the nucleus.

Mass number The combined number of protons and neutrons in the nucleus.

Nuclide and isotope A nuclide is an entity containing a unique number of protons and neutrons in the

nucleus. For nuclides of the same element the number of protons remains the same

but the number of neutrons may vary. Such nuclides are known collectively as the

isotopes of the element. Although the term isotope implies plurality it is sometimes

used loosely in place of nuclide.

Isomer/isomeric state An isomer or isomeric state is a high energy state of a nuclide which may decay

by isomeric transition (IT) as described in the list of decay modes below, although

certain low-lying states may decay independently to other nuclides rather than the

ground state.

Half-life The time taken for the activity of a radioactive nuclide to fall to half of its previous

value.

Electron volt (eV) The energy acquired by any charged particle carrying a unit (electronic) charge when it

falls through a potential of one volt, equivalent to 1.602 × 10–19 J. The more useful

unit is the mega (million) electron volt (MeV).

Notes to Table I (Continued)

its inclusion in the 1946 table of Siegel (17, 18) and therefore the discovery of this

isotope by both Grummitt and Wilkinson (46) and Seelmann-Eggebert (47) in

1946 are considered to be independent.

L 106mRh Nervik and Seaborg (49) also observed this isotope in 1955 but tentatively

assigned it to 107Rh.

M 107Rh First observed by Born and Seelmann-Eggebert (73) in 1943 as a non-specific

activity and also tentatively identified by Glendenin (74, 75) in 1944.

N 108Rh Although credited with the discovery, the claim by Baró, Rey and Seelmann-

Eggebert (50) is considered to be tentative and a more definite claim to the

discovery was made by Baumgärtner, Plata Bedmar and Kindermann (76)

in 1957.

O 118Rh Bernas et al. (63) only confirmed that the isotope was particle stable. The half-life

was first determined by Jokinen et al. (77) in 2000.

P 119Rh and 121Rh Bernas et al. (63) only confirmed that the isotopes were particle stable. The half-

lives were first determined by Montes et al. (78) in 2005.

Q 120Rh Bernas et al. (63) only confirmed that the isotope was particle stable. The half-life

was first determined by Walters et al. (79) in 2004.



Decay Modes

α Alpha decay is the emission of alpha particles which are 4He nuclei. Thus the atomic

number of the daughter nuclide is two lower and the mass number is four lower.

β– Beta or electron decay for neutron-rich nuclides is the emission of an electron (and an

anti-neutrino) as a neutron in the nucleus decays to a proton. The mass number of the

daughter nuclide remains the same but the atomic number increases by one.

β+ Beta or positron decay for neutron-deficient nuclides is the emission of a positron (and a neutrino)

as a proton in the nucleus decays to a neutron. The mass number of the daughter nuclide remains

the same but the atomic number decreases by one. However this decay mode cannot occur unless

the decay energy exceeds 1.022 MeV (twice the electron mass in energy units). Positron decay is

always associated with orbital electron capture (EC).

EC Orbital electron capture in which the nucleus captures an extranuclear (orbital) electron

which reacts with a proton to form a neutron and a neutrino, so that, as with positron

decay, the mass number of the daughter nuclide remains the same but the atomic number

decreases by one.

IT Isomeric transition in which a high energy state of a nuclide (isomeric state or isomer)

usually decays by cascade emission of γ (gamma) rays (the highest energy form of electromagnetic

radiation) to lower energy levels until the ground state is reached.

p Proton decay in which a proton is emitted from the nucleus so both the atomic number and mass

number decrease by one. Such a nuclide is said to be ‘particle unstable’.

n Neutron decay in which a neutron is emitted from the nucleus so the atomic number remains

the same but the atomic mass is decreased by one. Such a nuclide is said to be ‘particle

unstable’.

Erratum: In the previous reviews (1–4) the alpha and beta decay modes were described in terms of ‘emittance’. This should

read ‘emission’.

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The Author John W. Arblaster is interested inthe history of science and theevaluation of the thermodynamic andcrystallographic properties of theelements. Now retired, he previouslyworked as a metallurgical chemist in anumber of commercial laboratoriesand was involved in the analysis of awide range of ferrous and non-fer-rous alloys.



Reviewed by Stewart Brown

Johnson Matthey Precious Metals Marketing,Orchard Road, Royston, Hertfordshire SG8 5HE, UK;


Introduction“Asymmetric Catalysis on Industrial Scale: Challenges,

Approaches and Solutions”, edited by Hans-Ulrich

Blaser and Hans-Jürgen Federsel, builds and

expands upon its first edition, which was published

in 2004 (1). The second edition provides the reader

with a comprehensive examination of the industrially

important aspects of asymmetric catalysis, an area of

organic chemistry that introduces chirality (a mole-

cule that is non-superimposable upon its mirror

image) to a molecule.This is especially important for

pharmaceuticals, as biologically active compounds

are often chiral molecules.

One of the book’s co-editors, Hans-Ulrich Blaser,

is currently Chief Technology Officer at Solvias in

Basel, Switzerland, having previously spent twenty

years at Ciba and three years at Novartis.The other co-

editor, Hans-Jürgen Federsel, is Director of Science for

Pharmaceutical Development at AstraZeneca in

Sweden. He is recognised as a specialist in process

research and development where he has worked for

over 30 years.

The monograph is divided into 28 chapters, each

containing stand-alone case studies of a particular

chemical or biocatalytic process. This makes the text

very easy to dip in and out of, or alternatively to look

for specific examples of interest. The book highlights

real world processing issues, showing how each has

been tackled and solved by the authors. The main

aim of this book is to show that asymmetric catalysis

is not merely the preserve of academic research;

rather, it is a large-scale production tool for industrial

manufacturing. However, just as importantly it pro-

vides support and ideas for those suffering with simi-

lar issues in optimising industrial syntheses.

The reader of this book is required to have a rela-

tively advanced knowledge of organic chemistry in

order to fully appreciate the complexities of the vast

range of reactions covered. It is aimed primarily at



“Asymmetric Catalysis on IndustrialScale”, 2nd EditionEdited by Hans-Ulrich Blaser (Solvias AG, Switzerland) and Hans-Jürgen Federsel(AstraZeneca, Sweden), Wiley-VCH, Weinheim, Germany, 2010, 580 pages,ISBN: 978-3-527-32489-7, £140, €168, US$360 (Print version); e-ISBN: 9783527630639,doi:10.1002/9783527630639 (Online version)


postgraduate level and particularly at those involved

in the pharmaceutical and process chemistry indus-

tries.The book combines both organic chemistry and

biochemistry in almost equal measure and so a good

understanding of biological compounds and reac-

tions is also required.

Asymmetric Catalysis by thePlatinum Group MetalsThe chapters are written by a grand total of 87 dif-

ferent authors from a plethora of pharmaceutical

companies around the world, as well as a few chemi-

cals companies and universities. The lengths of the

chapters are such that a solid overview is provided,

without overloading the reader with information. All

reaction schemes are well drawn and are generally

complemented with graphs and spectra of the synthe-

sised compounds, as well as some photographs and

process flow sheets to demonstrate some very elegant

engineering solutions. Furthermore, the chapters are

well referenced, allowing easy access to further infor-

mation and literature should the reader so require.

Due to the broad scope of this book, in terms of

the variety of reactions and processes covered, this

review will only focus on those involving platinum

group metal (pgm) catalysts. It will not cover non-

pgm catalytic processes or those involving biologi-

cal catalysis, of which there are many interesting

examples.

In terms of coverage, as expected in this particular

field, the pgms feature heavily throughout, with one

or more of the metals being referred to in 17 of the

28 chapters. In fact, Chapter 20, which examines

asymmetric hydrogenation for the design of drug

substances, features all five of the pgms that are

most widely used for catalytic applications: platinum,

palladium, rhodium, iridium and ruthenium.

Interestingly, the book is arranged by process rather

than perhaps a more orthodox method of segmenting

by catalyst type or chemical transformation. The rea-

soning behind this is that it enables readers to find

out how particular issues have been solved on a

process level, which should prove useful to the indus-

trial practitioner.

The chapters are grouped into three sections:

• Part I:‘New Processes for Existing Active

Compounds (APIs)’;

• Part II:‘Processes for Important Building Blocks’;

• Part III:‘Processes for New Chemical Entities

(NCEs)’.

Throughout this book the importance of process

development and scale-up, taking laboratory-scale

products to pilot plant and subsequently full-scale

production of active, pure products is impressed

upon the readers.

The range of enantioselective catalysis shown in

this book highlights the growing importance of

developing more selective, active and ultimately

more cost-effective processes for the production of

specific biologically active compounds.

New Processes for Existing Active CompoundsThe first section of the book contains five chapters,

each of which examines either new catalysts or new

routes to produce existing compounds for such prod-

ucts as cholesterol-lowering, cough-relieving or anti-

obesity drugs, as well as vitamins and indigestion

remedies. Asymmetric hydrogenations catalysed by

Ru, Ir or Rh feature heavily, especially in Chapter 2 in

which Kurt Püntener and Michelangelo Scalone

(F. Hoffmann-La Roche Ltd, Switzerland) present five

example syntheses showing how the hydrogenation

of different functional groups has led to significant

improvements in the production of active pharma-

ceutical intermediates (APIs).

Chapter 3 takes a detailed look at the use of asym-

metric hydrogenation in the production of (+)–biotin

(vitamin H). This compound has three stereocentres

that need to be controlled to produce the pure,

active compound that can produce full biological

activity in the body. The reader is led through the

history of biotin production (today a 100 tonne per

year industry) from the original eleven-step Goldberg-

Sternbach concept involving a palladium-catalysed

hydrogenation step, through to the much shorter and

more elegant Lonza process, utilising a rhodium-

catalysed asymmetric hydrogenation step (Scheme I).

The often lengthy reaction schemes are very well

drawn out and highlight the complexities associated

with this particular synthesis.

Chapter 5 covers the important reaction of asym-

metric ketone reduction, which despite being aca-

demically well understood poses significant issues

in complex biological molecules on an industrial

scale. This chapter highlights the groundbreaking

work by Ryoji Noyori, who won the 2001 Nobel Prize

in Chemistry with William S. Knowles for their work

on chiral hydrogenation reactions catalysed by Rh

and Ru complexes (2). This has influenced the work

in this chapter and much of the rest of the book.



Andreas Marc Palmer (Nycomed GmbH, Germany)

and Antonio Zanotti-Gerosa (Johnson Matthey

Catalysis and Chiral Technologies, UK) tell the story of

how selectivity and activity can be tuned by the opti-

misation of ruthenium phosphine complexes such as

those shown in Figure 1 for large-scale reactions.

Processes for Important Building BlocksThe second section contains fourteen chapters cate-

gorised as new catalyst and process developments

for synthetically important building blocks, nine of

which mention pgms. Chapter 16 in particular

demonstrates the effectiveness of pgms with mention

given to Pd, Rh, Ir and Ru in a particularly in-depth

analysis of asymmetric transfer hydrogenation.

The technique of asymmetric transfer hydrogena-

tion is an important method for producing optically

active alcohols and amines (for example, Scheme II).

The authors spend considerable time in this chapter

discussing the reaction components before moving

on to some case studies to illustrate their use. This is

certainly one of the most detailed chapters, and it is

well supported by a series of tables, reaction schemes

and graphs.

Processes for New Chemical EntitiesThe final section is the least relevant in terms of

pgm use, with five of the remaining nine chapters not

featuring the metals. However, one of the stand-

out reviews in terms of pgm catalysis is Chapter 20.



Scheme I. The Lonzaconcept: (+)-biotinprocess usingasymmetrichydrogenationcatalysed by arhodium(I) complex

Fig. 1. Two examplesof ruthenium phos-phine complexesused as catalysts forthe asymmetricreduction of ketones

This chapter, entitled ‘Enabling Asymmetric

Hydrogenation for the Design of Efficient Synthesis of

Drug Substances’ and written by Yongkui Sun, Shane

Krska, C. Scott Shultz and David M. Tellers (Merck &

Co, Inc, USA), includes examples of catalysed steps

involving platinum, palladium, rhodium, iridium and

ruthenium during the course of the text.

The chapter begins with an introduction once

again paying tribute to the great work by Knowles

and Noyori in the field of asymmetric hydrogenation.

It then talks about the work done by Merck chemists

to increase the use of asymmetric catalysis in drug

discovery programmes within the company.The chap-

ter drives home the key message that by identifying

and having a concerted effort to utilise and improve

a particular reaction, unprecedented progress could

be made.

Three detailed case studies born out of Merck’s

‘Catalysis Initiative’ are then recounted: laropiprant,

an API in the cholesterol-lowering drug TredaptiveTM;

taranabant, an API in the treatment of obesity; and

sitagliptin, an API in the treatment of type 2 diabetes

(Figure 2) (Scheme III). All three demonstrate the

vital importance of high-throughput screening to

optimise both catalyst and reaction conditions

within a constrained time-frame.The whole chapter is

a success story for the Merck ‘Catalysis Initiative’ and

should serve as inspiration to other companies in

the search for new methods for large-scale drug

production.

ConclusionsThis book contains a comprehensive examination of

a wide range of industrially important asymmetric

reactions. It clearly shows the difficulties and chal-

lenges associated with these reactions, and more

importantly how scientists and engineers have man-

aged to successfully overcome them. The pgms fea-

ture in a large proportion of the syntheses and

processes mentioned, with palladium-catalysed

hydrogenations and the work of Knowles and Noyori

being particularly significant.

The book is easy to read and well illustrated and

referenced throughout. The decision to group the

chapters by the nature of the process works well,

with the tables at the front of the book easily

directing readers to subjects of interest. The key aim

of this book, to show that asymmetric catalysis is not

merely the preserve of academic research, is driven

home in every chapter. The relevance of each reac-

tion and synthesis to the industrial environment is

made abundantly clear through a wide array of case

studies.

Overall, this book will be of interest to both indus-

trial specialists and academics as it contains a good

mix of chemistry and engineering. It provides com-

fort and inspiration to those working in this field

through the numerous success stories told and is

undoubtedly a useful source of potential contacts

for those struggling with a particular asymmetric

synthesis issue.



Scheme II. Rhodium-catalysed asymmetrictransfer hydrogenation reactioninvestigated for the synthesis of a keyintermediate of duloxetine

Fig. 2. The structures of laropiprant, taranabant and sitagliptin



“AsymmetricCatalysis onIndustrialScale”, 2ndEdition

References1 “Asymmetric Catalysis on Industrial Scale: Challenges,

Approaches and Solutions”, eds. H.-U. Blaser andE. Schmidt, Wiley-VCH, Weinheim, Germany, 2004

2 ‘Advanced Information on the Nobel Prize in Chemistry2001, Catalytic Asymmetric Synthesis’, The RoyalSwedish Academy of Sciences, Stockholm, Sweden,10th October, 2001

The ReviewerDr Stewart Brown graduated with an MChem(Hons) and a PhD in Chemistry from theUniversity of Liverpool, UK. He joined JohnsonMatthey in 2004 and spent 5 years as aProcess Development Chemist, involved in thescale-up of new catalysts and processes for theEmission Control Technologies business unit.In 2009 he transferred to Precious MetalsMarketing and is currently a Market Analystwithin the Market Research team, focusingon the chemical, electronics, automotive andpetroleum refining sectors.

Scheme III. First generation route to sitagliptin. BINAP = 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl; EDC = N-(3-dimethylaminopropyl)-N‘-ethylcarbodiimide hydrochloride; DIAD = di-isopropyl azodicarboxylate;NMM = N-methylmorpholine


doi:10.1595/147106711X570631 •Platinum Metals Rev., 2011, 5555, (2), 140–141•

BOOKS

““HHeeaalltthhyy,, WWeeaalltthhyy,, SSuussttaaiinnaabbllee WWoorrlldd””

J. Emsley (UK), Royal Society ofChemistry, Cambridge, UK, 2010,248 pages, ISBN 978-1-84755-862-6,£18.99

The themes of this general read-

er book relate to the impor-

tance of chemistry in everyday

life, the benefits chemicals cur-

rently bring, and how the use of

chemicals can continue on a

sustainable basis. Topics cov-

ered include: health, food (the role of agrochemicals

and food chemists),water (drinking water; the seas as

a source of raw materials), fuels,plastics (can they be

sustainable?), cities and sport.

““MMooddeerrnn EElleeccttrrooppllaattiinngg””,, 55tthh EEddiittiioonn

Edited by M. Schlesinger (Universityof Windsor, Windsor, Ontario,Canada) and M. Paunovic (USA),John Wiley & Sons, Inc, Hoboken,New Jersey, USA, 2010, 736 pages,ISBN 978-0-470-16778-6, £100.00,€120.00, US$149.95; e-ISBN:9780470602638

This expanded new edition

places emphasis on electroplat-

ing and electrochemical plating in nanotechnolo-

gies, data storage and medical applications. It

includes chapters on ‘Palladium Electroplating’ and

‘Electroless Deposition of Palladium and Platinum’.

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Edited by T. Shioiri (Japan), K. Izawa(Ajinomoto Co, Inc, Japan) andT. Konoike (Shionogi & Co, Ltd,Japan), Wiley-VCH Verlag GmbH &Co KGaA, Weinheim, Germany, 2011,526 pages, ISBN 978-3-527-32650-1,£125.00, €150.00, US$210.00;e-ISBN 9783527633678

This book covers the basic

chemistry needed for future

developments and key tech-

niques in the pharmaceutical industry, as well as

morphology, engineering and regulatory issues.

Recent examples of industrial production of active

pharmaceutical ingredients are given. It includes

chapters on ‘Development of Palladium Catalysts for

Chemoselective Hydrogenation’, ‘Silicon-Based

Carbon–Carbon Bond Formation by Transition Metal

Catalysis’ and ‘Direct Reductive Amination with

Amine Boranes’.

JOURNALS

GGeeoosscciieennccee FFrroonnttiieerrss

Editor-in-Chief: X. X. Mo (ChinaUniversity of Geosciences (Beijing),China); China University ofGeosciences (Beijing), PekingUniversity and Elsevier BV; ISSN1674-9871

Geoscience Frontiers (GSF) is a

new quarterly journal under the

joint sponsorship of the China

University of Geosciences

(Beijing) and Peking University. Co-published with

Elsevier, GSF publishes original research articles and

reviews of recent advances in all fields of earth sci-

ences. Technical papers, case histories, reviews and

discussions are included.

GGrreeeennhhoouussee GGaasseess:: SScciieennccee aanndd TTeecchhnnoollooggyy

Edited by Mercedes Maroto-Valer(Centre for Innovation in CarbonCapture and Storage (CICCS), Uni-versity of Nottingham, UK) andCurtis Oldenburg (Geologic CarbonSequestration (GCS) Program,Lawrence Berkeley National Labora-tory, USA); Society of ChemicalIndustry and John Wiley & Sons, Ltd;e-ISSN 2152-3878

Greenhouse Gases: Science and Technology (GHG) is

a new quarterly online journal from the Society of

Chemical Industry (SCI) and Wiley. GHG is dedicated

to the management of greenhouse gases through cap-

ture, storage, utilisation and other strategies. GHG will

explore subject areas such as:

(a) Carbon capture and storage;

(b) Utilisation of carbon dioxide (CO2);

(c) Other greenhouse gases: methane (CH4), nitrous

oxide (N2O), halocarbons;

(d) Other mitigation strategies.

Publications in Brief



HHiigghh--TTeemmppeerraattuurree MMaatteerriiaallss

JOM, 2010, 6622, (10)

The theme of this issue of JOM

is high-temperature materials

which includes the following

four articles on the topic of

nickel-based superalloys:

TThhee TThheerrmmooddyynnaammiicc MMooddeelliinngg ooffPPrreecciioouuss--MMeettaall--MMooddiiffiieedd NNiicckkeellBBaasseedd SSuuppeerraallllooyyss

F. Zhang, J. Zhu, W. Cao, C. Zhang and Y. A. Chang, JOM,2010, 6622, (10), 35

PPrreecciioouuss--MMeettaall--MMooddiiffiieedd NNiicckkeell--BBaasseedd SSuuppeerraallllooyyss::MMoottiivvaattiioonn aanndd PPootteennttiiaall IInndduussttrryy AApppplliiccaattiioonnss

A. Bolcavage and R. C. Helmink, JOM, 2010, 6622, (10), 41

TThhee UUssee ooff PPrreecciioouuss--MMeettaall--MMooddiiffiieedd NNiicckkeell--BBaasseeddSSuuppeerraallllooyyss ffoorr TThhiinn GGaaggee AApppplliiccaattiioonnss

D. L. Ballard and A. L. Pilchak, JOM, 2010, 6622, (10), 45

AA CCoommbbiinneedd MMaappppiinngg PPrroocceessss ffoorr tthhee DDeevveellooppmmeenntt ooffPPllaattiinnuumm--MMooddiiffiieedd NNii--BBaasseedd SSuuppeerraallllooyyss

A. J. Heidloff, Z. Tang, F. Zhang and B. Gleeson, JOM, 2010,6622, (10), 48

2211sstt IInntteerrnnaattiioonnaall SSyymmppoossiiuumm oonn CChheemmiiccaall RReeaaccttiioonn

EEnnggiinneeeerriinngg ((IISSCCRREE 2211))

Ind. Eng. Chem. Res., 2010, 4499, (21),10153–11120

ISCRE 21 was held in

Philadelphia, Pennsylvania, USA,

from 13th–16th June 2010. The

symposium focused on the role

of chemical reaction engineer-

ing in addressing resource sus-

tainability, environmental and

life science challenges. The topics covered included

rational design of catalysts, computational catalysis,

reaction path analysis, dynamics of chemical reac-

tors, multiphase and reacting flows, environmental

reaction engineering, microreactors, membrane reac-

tors, process intensification, fuel cells, bioderived

chemicals and fuels, clean coal conversion processes,

CO2 capture and utilisation,hydrogen production and

utilisation, and novel functional materials. This ISCRE

21 special issue of Industrial & Engineering Chemistry

Research consists of Invited Perspectives by the

plenary speakers, as well as regular, full-length con-

tributed papers by the other authors.

RReecceenntt AAddvvaanncceess iinn tthhee iinn--ssiittuu CChhaarraacctteerriizzaattiioonn ooff

HHeetteerrooggeenneeoouuss CCaattaallyyssttss

Chem. Soc. Rev., 2010, 3399, (12),4541–5072

The 28 review articles of this

themed issue of Chemical

Society Reviews cover the advan-

tages, limitations, challenges

and future possibilities of in situ

characterisation techniques for

“elucidating the ‘genesis’ and

working principles of heterogeneous catalysts”. Bert

Weckhuysen (Inorganic Chemistry and Catalysis

Group, Debye Institute for Nanomaterials Science,

Utrecht University, The Netherlands) assembled this

issue on in situ characterisation of catalytic solids.

ON THE WEB

GGlloobbaall EEmmiissssiioonnss MMaannaaggeemmeenntt

Latest issue: Volume 3, Issue 01(November 2010)

Johnson Matthey Environ-

mental Catalysts and Tech-

nologies’ Global Emissions

Management (GEM) publi-

cation featuring developments in emissions control is

now online. Free subscription to GEM online allows

subscribers to:

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Find this at: http://www.jm-gem.com/

http://www.jm-gem.com/



CATALYSIS – APPLIED AND PHYSICAL

ASPECTS

CCoonnttrroolllleedd SSyynntthheessiiss ooff PPtt NNaannooppaarrttiicclleess vviiaa SSeeeeddiinngg

GGrroowwtthh aanndd TThheeiirr SShhaappee--DDeeppeennddeenntt CCaattaallyyttiicc AAccttiivviittyy

X. Gong, Y. Yang, L. Zhang, C. Zou, P. Cai, G. Chen and

S. Huang, J. Colloid Interface Sci., 2010, 335522, (2), 379–385

Octahedral,cuboctahedral,branched and ‘rice-like’Pt

NPs were synthesised using a seed-mediated growth

route. Pt NPs (3 nm) were prepared and dispersed in

oleyl amine to form a seed solution and then

Pt(acac)2 was added. By adjusting the molar ratio of

Pt from Pt(acac)2 and seed NPs, the seed diameter

and the addition route of Pt(acac)2, the NPs growth

could be controlled to fall into in a kinetic or thermo-

dynamic growth regime. The obtained NPs were

supported on C black (Vulcan XC-72). The catalysts

synthesised from branched NPs were found to have

higher catalytic activity and stability for the oxidation

of methanol.

PPyyrroopphhoorriicciittyy aanndd SSttaabbiilliittyy ooff CCooppppeerr aanndd PPllaattiinnuumm

BBaasseedd WWaatteerr--GGaass SShhiifftt CCaattaallyyssttss dduurriinngg OOxxiiddaattiivvee

SShhuutt--DDoowwnn//SSttaarrtt--UUpp

R. Kam, J. Scott, R. Amal and C. Selomulya, Chem. Eng. Sci.,

2010, 6655, (24), 6461–6470

In this investigation Cu/ZnO exhibited high levels of

pyrophoricity.This manifested as a sharp temperature

rise of the catalyst bed upon air introduction. Severe

sintering of the bulk and metallic phases of the cata-

lyst resulted in catalyst deactivation.No pyrophoricity

was observed for Pt-based catalysts; however, there

was sintering of the metallic phase in Pt/TiO2 and

Pt/ZrO2. Pt/CeO2 retained its activity, displaying no

loss in specific surface area or metal dispersion.

SShhaappee--SSeelleeccttiivvee FFoorrmmaattiioonn aanndd CChhaarraacctteerriizzaattiioonn ooff

CCaattaallyyttiiccaallllyy AAccttiivvee IIrriiddiiuumm NNaannooppaarrttiicclleess

S. Kundu and H. Liang, J.

Colloid Interface Sci., 2011,

335544, (2), 597–606

Sphere, chain, flake and

needle shaped Ir NPs

were synthesised via

reduction of Ir(III) ions in

c e t y l t r i m e t hy l a m m o -

nium bromide micellar

media containing alkaline

2,7-dihydroxynaphthalene under UV irradiation. The

NPs’ morphology was tuned by changing the surfac-

tant:metal ion molar ratios and altering other param-

eters.The Ir nano-needles were a good catalyst for the

reduction of organic dyes in presence of NaBH4.

CATALYSIS – REACTIONS

SSeelleeccttiivvee OOxxiiddaattiioonn ooff GGlluuccoossee OOvveerr CCaarrbboonn--

SSuuppppoorrtteedd PPdd aanndd PPtt CCaattaallyyssttss

I. V. Delidovich, O. P. Taran, L. G. Matvienko, A. N. Simonov,

I. L. Simakova, A. N. Bobrovskaya and V. N. Parmon, Catal.

Lett., 2010, 114400, (1–2), 14–21

Pt/C exhibited lower specific activity and provided

poor selectivity of glucose oxidation to gluconic acid

by O2 in comparison with Pd/C. The finely dispersed

Pd/C catalysts are prone to deactivation due to oxida-

tion of their surface, while larger metal particles are

more tolerant and stable. The activity of Pd nano-

particles can be maintained when the process is

controlled by diffusion of O towards the active com-

ponent of the catalyst.

CCaarrbboonnaatteess:: EEccoo--FFrriieennddllyy SSoollvveennttss ffoorr PPaallllaaddiiuumm--

CCaattaallyysseedd DDiirreecctt AArryyllaattiioonn ooff HHeetteerrooaarroommaattiiccss

J. J. Dong, J. Roger, C. Verrier, T. Martin, R. Le Goff, C. Hoarau

and H. Doucet, Green Chem., 2010, 1122, (11), 2053–2063

Direct 2-,4- or 5-arylation of heteroaromatics with aryl

halides using PdCl(C3H5)(dppb) as catalyst precur-

sor/base was shown to proceed in moderate to good

yields using the solvents diethylcarbonate (see the

FFiigguurree) or propylene carbonate.The best yields were

obtained using benzoxazole or thiazole derivatives

(130ºC). The arylation of furan, thiophene, pyrrole,

imidazole or isoxazole derivatives was found to

require a higher reaction temperature (140ºC).

Abstracts

J. J. Dong et al., Green Chem., 2010, 1122, (11), 2053–2063

EMISSIONS CONTROL

AA GGlloobbaall DDeessccrriippttiioonn ooff DDOOCC KKiinneettiiccss ffoorr CCaattaallyyssttss

wwiitthh DDiiffffeerreenntt PPllaattiinnuumm LLooaaddiinnggss aanndd AAggiinngg SSttaattuuss

K. Hauff, U. Tuttlies, G. Eigenberger and U. Nieken, Appl.

Catal. B: Environ., 2010, 110000, (1–2), 10–18

Five Pt/γ-Al2O3 DOCs with different Pt loadings and

ageing steps were characterised with regards to Pt

particle diameter, active surface area and conversion

behaviour for CO, propene and NO oxidation.

HR-REM showed that the Pt particles have diameters

larger than 8 nm. The catalyst activity was shown to

be directly proportional to the catalytically active sur-

face area, which was determined by CO chemisorp-

tion measurements. In order to model the CO and

propene oxidation kinetics, only the catalytically

active surface has to be changed in the global

kinetic models. The same was true for NO oxidation

at higher temperatures.

FUEL CELLS

HHiigghh PPllaattiinnuumm UUttiilliizzaattiioonn iinn UUllttrraa--LLooww PPtt LLooaaddeedd

PPEEMM FFuueell CCeellll CCaatthhooddeess PPrreeppaarreedd bbyy EElleeccttrroosspprraayyiinngg

S. Martin, P. L. Garcia-Ybarra and J. L. Castillo, Int. J.

Hydrogen Energy, 2010, 3355, (19), 10446–10451

The title cathodes with Pt loadings as low as 0.012 mg

Pt cm–2 were prepared by the electrospray method.

SEM of these layers showed a high dispersion of the

catalyst powders forming fractal deposits made by

small clusters of Pt/C NPs, with the clusters arranging

in a dendritic growth. Using these cathodes in MEAs,

a high Pt utilisation in the range 8–10 kW g–1 was

obtained for a fuel cell operating at 40ºC and atmos-

pheric pressure.Moreover,a Pt utilisation of 20 kW g–1

was attained at 70ºC and 3.4 bar over-pressure.

EEffffeecctt ooff MMEEAA FFaabbrriiccaattiioonn TTeecchhnniiqquueess oonn tthhee CCeellll

PPeerrffoorrmmaannccee ooff PPtt––PPdd//CC EElleeccttrrooccaattaallyysstt ffoorr OOxxyyggeenn

RReedduuccttiioonn iinn PPEEMM FFuueell CCeellll

S. Thanasilp and M. Hunsom, Fuel, 2010, 8899, (12),

3847–3852

The effect of three different MEA fabrication tech-

niques: catalyst-coated substrate by direct spray

(CCS), catalyst-coated membrane by direct spray

(CCM-DS) or decal transfer (CCM-DT), on the O2

reduction in a PEMFC was investigated under identi-

cal Pt-Pd/C loadings. The cells prepared by the CCM

methods, and particularly by CCM-DT, exhibited a sig-

nificantly higher open circuit voltage (OCV) but a

lower ohmic and charge transfer resistance. By using

CV with H2 adsorption, it was found that the electro-

chemically active area of the electrocatalyst prepared

by CCM-DT was higher than those by CCS and

CCM-DS. Under a H2/O2 system at 0.6 V, the cells

with an MEA made by CCM-DT provided the highest

cell performance (~350 mA cm–2).

METALLURGY AND MATERIALS

SShhaappee MMeemmoorryy EEffffeecctt aanndd PPsseeuuddooeellaassttiicciittyy ooff TTiiPPtt

Y. Yamabe-Mitarai, T. Hara, S. Miura and H. Hosoda,

Intermetallics, 2010, 1188, (12), 2275–2280

Martensitic transformation behaviour and SM prop-

erties of Ti-50 at%Pt SMA were investigated using

high-temperature XRD and loading–unloading com-

pression tests. The structures of the parent and

martensite phases were identified as B2 and B19,

respectively. Strain recovery was observed during

unloading at RT and at 1123 K, which was below the

martensite temperature. Shape recovery was investi-

gated for the samples by heating at 1523 K for 1 h. The

strain recovery rate was 30–60% for the samples tested

at RT and ~11% for the samples tested at 1123 K.

RRoollee ooff SSeevveerree PPllaassttiicc DDeeffoorrmmaattiioonn oonn tthhee CCyycclliicc

RReevveerrssiibbiilliittyy ooff aa TTii5500..33NNii3333..77PPdd1166 HHiigghh TTeemmppeerraattuurree

SShhaappee MMeemmoorryy AAllllooyy

B. Kockar, K. C. Atli, J. Ma, M. Haouaoui, I. Karaman, M.

Nagasako and R. Kainuma, Acta Mater., 2010, 5588, (19),

6411–6420

The effect of microstructural refinement on the ther-

momechanical cyclic stability of the title HTSMA

which was severely plastically deformed using equal

channel angular extrusion (ECAE) was investigated.

The grain/subgrain size of the high temperature

austenite phase was refined down to ~100 nm. The

increase in strength differential between the onset of

transformation and the macroscopic plastic yielding

after ECAE led to enhancement in the cyclic stability

during isobaric cooling–heating. The reduction in

irrecoverable strain levels is attributed to the increase

in critical stress for dislocation slip due to the

microstructural refinement during ECAE.

CHEMISTRY

TThhee CChheemmiissttrryy ooff TTrrii-- aanndd HHiigghh--NNuucclleeaarriittyy

PPaallllaaddiiuumm((IIII)) aanndd PPllaattiinnuumm((IIII)) CCoommpplleexxeess

V. K. Jain and L. Jain, Coord. Chem. Rev., 2010, 225544,

(23–24), 2848–2903



This review gives an overview of the title complexes

and reports developments. Three or more square-

planar metal atoms can be assembled in several ways

resulting in complexes with a myriad of geometric

forms.These square planes may be sharing a corner,

an edge and two edges or even separated by ligands

having their donor atoms incapable of forming

chelates, yielding dendrimers and self-assembled

molecules. Synthetic, spectroscopic and structural

aspects of these complexes together with their appli-

cations are described. (Contains 554 references.)

ELECTRICAL AND ELECTRONICS

DDiissssoolluuttiioonn aanndd IInntteerrffaaccee RReeaaccttiioonnss bbeettwweeeenn

PPaallllaaddiiuumm aanndd TTiinn ((SSnn))--BBaasseedd SSoollddeerrss::

PPaarrtt II.. 9955..55SSnn--33..99AAgg--00..66CCuu AAllllooyy

P. T. Vianco, J. A. Rejent, G. L. Zender and P. F. Hlava, Metall.

Mater. Trans. A, 2010, 4411, (12), 3042–3052

The interface microstructures and dissolution behav-

iour which occur between Pd substrates and molten

95.5Sn-3.9Ag-0.6Cu (wt%) were studied. The solder

bath temperatures were 240–350ºC, and the immer-

sion times were 5–240 s.As a protective finish in elec-

tronic assemblies, Pd would be relatively slow to

dissolve into molten Sn-Ag-Cu solder. The Pd-Sn inter-

metallic compound (IMC) layer would remain suffi-

ciently thin and adherent to a residual Pd layer so as

to pose a minimal reliability concern for Sn-Ag-Cu

interconnections.

DDiissssoolluuttiioonn aanndd IInntteerrffaaccee RReeaaccttiioonnss bbeettwweeeenn

PPaallllaaddiiuumm aanndd TTiinn ((SSnn))--BBaasseedd SSoollddeerrss::

PPaarrtt IIII.. 6633SSnn--3377PPbb AAllllooyy

P. T. Vianco, J. A. Rejent, G. L. Zender and P. F. Hlava, Metall.

Mater. Trans. A, 2010, 4411, (12), 3053–3064

The interface microstructures as well as the rate

kinetics of dissolution and IMC layer formation were

investigated for couples formed between molten

63Sn-37Pb (wt%) and Pd sheet. The solder bath tem-

peratures were 215–320ºC, and the immersion times

were 5, 15, 30, 60, 120 and 240 s. The extents of Pd

dissolution and IMC layer development were signifi-

cantly greater for molten Sn-Pb than the Pb-free

Sn-Ag-Cu (Part I, as above) at a given test temperature.

ELECTROCHEMISTRY

TThhee EEffffeecctt ooff GGoolldd oonn PPllaattiinnuumm OOxxiiddaattiioonn iinn

HHoommooggeenneeoouuss AAuu––PPtt EElleeccttrrooccaattaallyyssttss

S. D. Wolter, B. Brown, C. B. Parker, B. R. Stoner and J. T.

Glass, Appl. Surf. Sci., 2010, 225577, (5), 1431–1436

Ambient air oxidation of Au-Pt thin films was carried

out at RT and then the films were characterised by

XPS. The homogeneous films were prepared by RF

cosputtering with compositions varying from Au9Pt91

to Au89Pt11 and compared to pure Pt and Au thin

films. The predominant oxidation products were PtO

and PtO2. Variations in Pt oxide phases and/or con-

centration did not contribute to enhanced electrocat-

alytic activity for oxygen reduction observed for the

intermediate alloy stoichiometries.

AA FFeeaassiibbiilliittyy SSttuuddyy ooff tthhee EElleeccttrroo--rreeccyycclliinngg ooff

GGrreeeennhhoouussee GGaasseess:: DDeessiiggnn aanndd CChhaarraacctteerriizzaattiioonn ooff aa

((TTiiOO22//RRuuOO22))//PPTTFFEE GGaass DDiiffffuussiioonn EElleeccttrrooddee ffoorr tthhee

EElleeccttrroossyynntthheessiiss ooff MMeetthhaannooll ffrroomm MMeetthhaannee

R. S. Rocha, L. M. Camargo, M. R. V. Lanza and R. Bertazzoli,

Electrocatalysis, 2010, 11, (4), 224–229

The title GDE was designed to be used in the elec-

trochemical conversion of CH4 into MeOH under

conditions of simultaneous O2 evolution. The GDE

was prepared by pressing and sintering TiO2(0.7)/

RuO2(0.3) powder and PTFE. CH4 was inserted into

the reaction medium by the GDE and electrosynthe-

sis was carried out in 0.1 mol l–1 Na2SO4. Controlled

potential experiments showed that MeOH concen-

tration increased with applied potential, reaching

220 mg l–1 cm2, at 2.2 V vs. a calomel reference elec-

trode. Current efficiency for MeOH formation was 30%.

PHOTOCONVERSION

CCyycclloommeettaallaatteedd RReedd IIrriiddiiuumm((IIIIII)) CCoommpplleexxeess

CCoonnttaaiinniinngg CCaarrbbaazzoollyyll--AAcceettyyllaacceettoonnaattee LLiiggaannddss::

EEffffiicciieennccyy EEnnhhaanncceemmeenntt iinn PPoollyymmeerr LLEEDD DDeevviicceess

N. Tian, Y. V. Aulin, D. Lenkeit, S. Pelz, O. V. Mikhnenko, P. W.

M. Blom, M. A. Loi and E. Holder, Dalton Trans., 2010, 3399,

(37), 8613–8615

New red emitting cyclometalated Ir(III) complexes

containing carbazolyl-acetylacetonate ligands (1, 2)

were prepared and then compared to the commonly

used reference emitter [(btp)2Ir(III)(acac)]. For a

range of concentrations the new complexes

revealed better luminous efficiencies than

[(btp)2Ir(III)(acac)]. The phosphorescence decay

times of the newly designed triplet emitters are

significantly shorter making them attractive

candidates for applications in advanced organic and

polymer LEDs.





11

N. Tian et al., Dalton Trans., 2010, 3399, (37), 8613–8615

22



CATALYSIS – APPLIED AND PHYSICALASPECTS

PPaallllaaddiiuumm((00)) CCoommpplleexx CCaattaallyysstt

Johnson Matthey Plc, World Appl. 2010/128,316

A Pd(0)Ln complex, where L is a ligand and

n = 2, 3 or 4, is prepared by reacting a Pd(II) complex

in a solvent with a base and ligand L. Further base,

optionally in a solvent, may be added to form the

Pd(0)Ln complex. The pre-formed Pd(0) complex

can be prepared on an industrial scale and used as a

catalyst in Pd-catalysed cross-coupling reactions.

When n = 2, the Pd(II) complex may not be

[(o-tol)3P]2PdCl2. The Pd(0)Ln complex may be, for

example, Pd[tBu2(p-PhMe2N)P]2 or Pd[tBu2(Np)P]2.

PPoollyymmeerr--SSuuppppoorrtteedd RRuutthheenniiuumm CCaattaallyyssttss

C.-M. Che and K.-W. M. Choi, US Appl. 2011/0,009,617

Non-crosslinked soluble polystyrene-supported Ru

nanoparticles were prepared by reacting

[RuCl2(C6H5CO2Et)]2 with polystyrene in air. The

supported Ru nanoparticles can be used to catalyse

intra- and intermolecular carbenoid insertion into

C–H and N–H bonds, alkene cyclopropanation and

ammonium ylide/[2,3]-sigmatropic rearrangement

reactions and can be recovered and reused ten times

without significant loss of activity.

DDiinnuucclleeaarr OOssmmiiuumm--RRhhooddiiuumm PPhhoottooccaattaallyysstt

Toyota Motor Corp, Japanese Appl. 2010-209,044

A dinuclear metal complex,for example 1,containing

a light-harvesting Os(tpy)22+ moiety and a catalytical-

ly active diphosphine Rh moiety can be used as a

photocatalyst for decomposing H2O to produce H2.

The photocatalyst is prepared by cross-coupling a ter-

pyridyl Os complex with phenylboronic acid pinacol

ester having a phosphinothioyl group in the presence

of a Pd catalyst to obtain the corresponding phos-

phine sulfide. This is reacted with Raney Ni to give a

diphosphine ligand having an Os(tpy)22+ moiety.

This ligand is mixed with a transition metal complex

such as [RhCl(CO)2]2 in a suitable solvent at room

temperature to obtain the dinuclear metal complex.

CATALYSIS – INDUSTRIAL PROCESS

PPaallllaaddiiuumm--CCaattaallyysseedd PPrreeppaarraattiioonn ooff IInntteerrmmeeddiiaatteess

Bayer CropScience AG, World Appl. 2011/003,530

Substituted and unsubstituted (2,4-dimethylbiphenyl-

3-yl)acetic acids and their esters are prepared via a

selective Suzuki cross-coupling reaction using

homogenous or heterogeneous Pd catalysts. 4-tert-

Butyl-2,6-dimethylphenyl acetic acid and 4-tert-butyl-

2,6-dimethyl mandelic acid, useful as intermediates

for pharmaceutical compounds or agricultural chem-

icals, are produced in good yield from inexpensive

starting materials.

FFiixxeedd--BBeedd PPllaattiinnuumm CCaattaallyysstt ffoorr HHyyddrroossiillyyllaattiioonn

Gelest Technol. Inc, US Appl. 2010/0,280,266

A recyclable fixed-bed catalyst complex containing a

silica-supported Pt carbene catalyst is claimed for use

in a hydrosilylation process between an olefin, sili-

cone or alkyne and a silicone to produce an

organofunctional silane and/or a crosslinked silicone

which contains <20 ppm residual Pt, preferably <10

ppm. The process can be repeated between 3–100

times over a period from 1 week to 1 year without

new addition of catalyst complex. It may be used in a

continuous reactor system.

RRhhooddiiuumm CCaattaallyyssttss ffoorr HHyyddrrooffoorrmmyyllaattiioonn

Eastman Chem. Co, US Patent 7,872,156 (2011)

Novel fluorophosphite compounds active for hydro-

formylation processes for ethylenically unsaturated

substrates are claimed. Catalyst solutions contain

20–300 mg l–1 Rh with a mole:atom gram ratio of fluo-

rophosphite:Rh between 1:1–200:1.The hydroformyla-

tion activity increases as the concentration of ligand

increases. Linear or branched aldehydes can be

Patents

Os

N

PR2

P

Rh

(PF6)2

11

Japanese Appl. 2010-209,044

R =phenyl, isopropyl, ethyl, tert-butyl, cyclohexyl,

propyl or naphthyl

CO

ClN N

N

N

N

R2

produced under standard hydroformylation reaction

conditions of 75–125ºC and 1–70 bar (15–1000 psig).

EMISSIONS CONTROL

HHiigghh PPaallllaaddiiuumm CCoonntteenntt DDiieesseell OOxxiiddaattiioonn CCaattaallyyssttss

Umicore AG & Co KG, World Appl. 2010/133,309

Pd-enriched DOCs are claimed for the oxidation of

CO and HC emissions from a compression ignition/

diesel engine. A first washcoat covers 25–95% of the

substrate from the inlet and may contain Pt:Pd in a

ratio for example 1:1; a second washcoat is richer in

Pd than the first washcoat,with a Pt:Pd ratio for exam-

ple 1:2, and covers 5–75% of the substrate from the

inlet.The catalysts are described as having increased

performance and hydrothermal durability under cold

start conditions.

PPllaattiinnuumm--PPaallllaaddiiuumm DDiieesseell OOxxiiddaattiioonn CCaattaallyysstt

BASF Corp, US Patent 7,875,573 (2011)

An exhaust gas treatment system includes a DOC

containing two washcoat layers coated onto a high

surface area support substantially free of silica. The

bottom washcoat layer contains Pt:Pd in a ratio

between 2:1–1:2 and does not contain a HC storage

component. The top washcoat layer contains Pt:Pd

in a ratio between 2:1–10:1 and one or more HC stor-

age components. A soot filter is located downstream

of the DOC and a NOx conversion catalyst is located

downstream of the soot filter.

FUEL CELLS

PPllaattiinnuumm aanndd PPaallllaaddiiuumm AAllllooyy EElleeccttrrooddeess

Danmarks Tekniske Univ., World Appl. 2011/006,511

Electrode catalysts formed from Pt or Pd, preferably

Pt, alloyed with Sc,Y and/or La on a conductive sup-

port material are claimed for use in a PEMFC. The cat-

alysts are described as having increased ORR activity,

comparable active site density and lower cost com-

pared to pure Pt. The activity enhancement is stable

over extended periods of time.

BBiinnaarryy aanndd TTeerrnnaarryy PPllaattiinnuumm AAllllooyy CCaattaallyyssttss

California Inst. Technol., US Appl. 2011/0,003,683

Pt-based alloys containing <50 at% Pt plus one or

more of Zr, Ti, Hf, Nb, Co, Ni, Fe, Pd, Ru, Rh, Re, Os or

Ir in a continuous film on a nanoparticle support are

claimed for use in the cathode of a PEMFC or a

DMFC. The alloy may be nanocrystalline with a grain

size <100 nm, preferably <10 nm. Preferred composi-

tions include (Pt3Co)100–yZry, where 0 ≤ y ≤ 30 at%;

or (Pt100–xCox)100–yZry, where 0 ≤ x ≤ 80 and 0.5 ≤ y ≤60 at%.

GGoolldd--PPllaattiinnuumm EElleeccttrrooddee CCaattaallyysstt

Toyota Motor Corp, Japanese Appl. 2010-211,946

A nanoscale catalyst layer for a FC is formed from a

Au core having average particle diameter <10 nm

with a Pt shell.The Au and Pt may form an alloy. Initial

activity is good and dissolution of Pt is suppressed.

METALLURGY AND MATERIALS

NNiicckkeell-- aanndd CCooppppeerr--FFrreeee WWhhiittee GGoolldd AAllllooyy

Rolex SA, European Appl. 2,251,444 (2010)

A white Au alloy free of Ni and Cu contains (in wt%):

>75 Au; 18–24 Pd; 1–6 In, Mn, Hf, Nb, Pt, Sn, Ta, V, Zn

and/or Zr; optionally >0.5 Si,Ga and/or Ti; and option-

ally >0.2 Ru, Ir and/or Re. The alloy is prepared by

placing the components in a crucible; melting the

components; pouring the molten alloy; allowing to

harden; quenching in water; subjecting to at least one

cold rolling; and annealing under reducing atmos-

phere. The alloy is described as having suitable

mechanical properties for watch making and jew-

ellery use, and does not require Rh plating.

IIrriiddiiuumm aanndd RRhhooddiiuumm AAllllooyyss wwiitthh IInnccrreeaasseedd SSttrreennggtthh

W. C. Heraeus GmbH, US Appl. 2010/0,329,922

Ir and Rh alloys with increased creep rupture strength

at high temperature, in particular at ~1800ºC, are

claimed.0.5–30 ppm B and 0.5–20 ppm Ca are added

to Zr- and Hf-free Ir, Rh or alloys thereof. The alloys

may also be free of Ti.The strengthened Ir alloys may

be used in Ir crucibles for growing single crystals

such as Nd:YAG laser crystals or in components for

the glass industry.

APPARATUS AND TECHNIQUE

PPaallllaaddiiuumm MMeemmbbrraannee ffoorr HHyyddrrooggeenn SSeeppaarraattiioonn

Korea Inst. Energy Res., US Patent 7,875,154 (2011)

A Pd alloy composite membrane for hydrogen sepa-

ration is prepared by depositing a layer of Pd on a

porous metal or ceramic support, preferably Ni, using

a dry sputtering deposition process; depositing a layer

of Cu on the Pd layer; and heat treating to form an

alloy. Optionally a first layer of Ag, Ni, Cu, Ru or Mo

may be formed before depositing Pd.



PPllaattiinnuumm AAppppaarraattuuss ffoorr PPrroodduucciinngg GGllaassss

Nippon Electric Glass Co Ltd, Japanese Appl. 2010-228,942

Glass manufacturing apparatus which reduces the

formation of bubbles in optical or display glass is

claimed. A dry coating containing a glass powder and

a ceramic powder is formed on the outer surface of a

Pt container. The coated Pt container is then sur-

rounded by a refractory layer containing >97 wt%

Al2O3 and SiO2 and fired.

ELECTRICAL AND ELECTRONICS

GGaass DDiisscchhaarrggee LLaammpp wwiitthh IIrriiddiiuumm EElleeccttrrooddee

Koninklijke Philips Electronics NV, US Appl. 2010/0,301,746

A gas discharge lamp includes a gas discharge vessel

filled with S, Se, Te or a compound thereof and an

electrode assembly in which the electron-emissive

material is 80–100 wt% Ir optionally alloyed with Ru,

Os, Rh, Pd or Pt. The Ir-based electrode has a high

melting point and resists chemical reaction with the

gas filling, providing a long-lived, efficient, compact

and high intensity white light source for applications

such as general and professional illumination.

IInntteeggrraatteedd RRhhooddiiuumm CCoonnttaaccttss

IBM Corp, US Patent 7,843,067 (2010)

A microelectronic structure contains an interconnect

barrier layer of Ta, Ti, W, Mo or their nitrides, between

a Rh contact structure and a Cu interconnect struc-

ture. Interdiffusion between Rh and Cu is prevented

and low resistance in microelectronic devices can be

achieved.

MEDICAL AND DENTAL

RRuutthheenniiuumm CCoommppoouunnddss ffoorr TTrreeaattiinngg CCaanncceerr

Univ. Strasbourg, World Appl. 2011/001,109

Ru compounds for treating proliferative diseases, in

particular cancer, are claimed, together with pharma-

ceutical compositions containing the same. Preferred

compounds include 1 and 2.



PF6–

PF6–

+

+

11

22

Ru

N

N N

N

N

Ru

N

N N

N

N

O

O

World Appl. 2011/001,109

Flame spray pyrolysis can be used to produce a

wide array of high purity nanopowders ranging

from single metal oxides such as alumina to more

complex mixed oxides, metals and catalysts. The

technique was first developed by the research group

of Sotiris E. Pratsinis at ETH Zurich, Switzerland (1).

Since then it has been used to create new and

sophisticated materials for catalysis and other

applications (2).

Johnson Matthey has developed its own Flame

Spray Pyrolysis Facility (FFiigguurree 11) which produces

a range of nanopowders using the flame spray pyrol-

ysis technique. It has the capacity to produce up to

100 g h−1 of nanopowder product, depending on the

material composition, and a number of process vari-

ables enable the preparation of well-defined target

materials.

How it Works

Flame spray pyrolysis is a one step process in which

a liquid feed – a metal precursor(s) dissolved in a

solvent – is sprayed with an oxidising gas into a flame

zone. The spray is combusted and the precursor(s)

are converted into nanosized metal or metal oxide

particles, depending on the metal and the operating

conditions. The technique is flexible and allows the

use of a wide range of precursors, solvents and

process conditions, thus providing control over parti-

cle size and composition.

Materials Synthesised

A range of oxide-based materials have been prepared

using the technique and some examples are illus-

trated in TTaabbllee II. Some of these materials find uses

in catalysis, electronics, thin film applications and



Flame Spray Pyrolysis: A UniqueFacility for the Production ofNanopowders

FFIINNAALL AANNAALLYYSSIISS

Fig. 1. Johnson Matthey’s development-scale Flame Spray Pyrolysis Facility, housed at the JohnsonMatthey Technology Centre, Sonning Common, UK. It offers a unique facility for the productionfor nanopowders



other areas. Additionally the transferable knowledge

gained can be applied to the synthesis of pgm cata-

lysts and supported pgm catalysts by the flame spray

method.

Case Study: A Palladium Catalyst for

Fine Chemicals Synthesis

A 2 wt% Pd/Al2O3 catalyst was prepared from an

organometallic palladium compound and an alu-

minium alkoxide in a organic solvent. The solution

was fed into the spray at 5 ml min−1 in an oxygen

stream of 5 l min−1. The spray was then combusted

with a pre-ignited flame of methane/oxygen. The

resulting product (FFiigguurree 22) had a specific surface

area of 145 m2 g−1 with a Pd dispersion around 30% as

determined by CO chemisorption.

The catalyst was tested in the hydrogenation of

nitrobenzene to produce aniline, using 0.5 g of

nitrobenzene in 5 ml of ethanol at 3 bar and 50ºC. Its

performance was found to be comparable to that of

commercially available Pd/Al2O3 and Pd/C catalysts.

This demonstrates that the Pd particles in the flame

spray samples are well dispersed throughout the sup-

port and give rise to a high metal surface area avail-

able for catalysis.

Study of the effects of the process parameters

including spray conditions and precursor chemistry

on catalyst characteristics is ongoing.

Conclusion

The flame spray pyrolysis technique allows for the

preparation of a vast range of materials, including

metastable phases, due to the rapid quenching

process. Johnson Matthey has dedicated much effort

to the application of the technique to the synthesis of

catalysts. Further scale-up will be critical and work is

ongoing via an EU funded project aimed at achieving

a production capacity over 10 kg h−1. To increase our

know-how and satisfy other interest areas, more work

utilising the technique is also ongoing via other EU

and UK Technology Strategy Board (TSB) funded

projects.

TTaabbllee II

PPrrooppeerrttiieess ooff SSeelleecctteedd MMeettaall OOxxiiddeess PPrreeppaarreedd bbyy FFllaammee SSpprraayy PPyyrroollyyssiiss

MMaatteerriiaall PPaarrttiiccllee ssiizzeeaa,, SSppeecciiffiicc ssuurrffaaccee PPhhaassee iiddeennttiiffiiccaattiioonnnnmm aarreeaabb,, mm22gg−−11

Al2O3 10–15 ~100 Mixture of γ- and δ-Al2O3

CeO2 10–15 80–100 Cubic CeO2

ZnO 8–15 60–90 Mainly tetragonal ZrO2

TiO2 25 80–100 Mainly anatase and trace of rutile

Doped TiO2 30 90–100 Mainly rutile and traces of anatase

aDetermined by TEM analysis

bDetermined by BET analysis

5 nm

Fig. 2. Transmission electron microscopy (TEM) imageof a flame made Pd/Al2O3 catalyst with Pd nanoparti-cles highlighted by red arrows

References1 R. Strobel, A. Baiker and S. E. Pratsinis, Adv. Powder

Technol., 2006, 1177, (5), 457

2 R. Strobel and S. E. Pratsinis, Platinum Metals Rev.,2009, 5533, (1), 11

The Author

Dr Bénédicte Thiébaut joined Johnson Matthey twelve years agoand worked on numerous projects specialising in the last sevenyears in the nanotechnology area. She initially investigated thesynthesis of nanomaterials by solution routes and turned herinterest to other methodologies including the flame spray pyrolysis(FSP) technique.



Acknowledgement

The creation of the development-scale Flame Spray

Pyrolysis Facility at JMTC, Sonning Common, was

partly funded by a grant provided by the UK’s for-

mer Department of Trade and Industry (DTI) under

its Micro and Nano Technology (“MNT”) Network

initiative.

DR BÉNÉDICTE THIÉBAUT

Johnson Matthey Technology Centre, Blounts Court,Sonning Common, Reading RG4 9NH UK

EE--mmaaiill:: tthhiieebbbb@@mmaatttthheeyy..ccoomm


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Jonathan ButlerPublications Manager

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Margery RyanEditorial Assistant

Keith WhitePrincipal Information Scientist

E-mail: [email protected]

Platinum Metals Review is the quarterly E-journal supporting research on the science and technology of the platinum group metals and developments in their application in industry


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