RADIATION FOR SCIENCE AND SOCIETY

Keywordsf-Block elementsCatalysisNanostruturesGaseous pollutantsFuels & Energy

C2TN members: Ana C. Ferreira1,* (C2TN Post-Doc), Joaquim Branco1, António Pereira Gonçalves2

Students: Pedro de Brito (MEC-Student)

* Email of corresponding author: acferreira@ctn.tecnico.ulisboa.pt

Collaborations1 1 Nuno Pinhão (IPFN/IST) | Non thermal plasma conversion of methane, Bobadela, Portugal2 Ana Ferraria and Ana Rego (IST/UL) | Catalysts surface characterization by XPS, Lisbon, Portugal

Funding

CATALYSIS(NANO STRUCTURES FOR CO2 REMOVAL AND FUELS PRODUCTION)

Thematic Strands

Earth Systems, Radioactivity and Cultural Heritage

C2TN/IST acknowledges the financial supportunder the project UID/Multi/04349/2013

http://c2tn.tecnico.ulisboa.pt

Advanced Materials

The main goals of Laboratory of Catalysis covers: i) the production of value-added chemicals and fuels, such as hydrocarbons, methanol or syngas, using

major gaseous pollutants (e.g. CO2, CH4, N2O) as raw materials; ii) the development, preparation and characterization of nanostructured intermetallic

compounds containing the f-block elements (lanthanides, Th and U), bimetallic oxides, metal borides, pnictides and chalcogenides with specific

functionalities and applications in environment and energy.

For catalytic studies, different heterogeneous systems

using transition metals and f-block elements as massic or

supported (SiO2 or Al2O3) catalysts were tested, either at

atmospheric pressure or under high pressure conditions.

Methanation of CO2

On the other hand, chalcogenides (e.g. Cu3SbS4 and

Cu12Sb4S13) and pnictides (e.g. CoSb3) were prepared

using unusual approaches, such as electrospinning and

solvothermal method.

PnictidesSkutterudite (CoSb3)• High-efficiency thermoelectric device application.• The high thermal conductivity of the binary skutterudite needs to be

reduced to further increase its efficiency.• Techniques to improve the thermal and electrical properties of the

skutterudite to enhance its thermoelectric efficiency: nanostructuredcompound and lanthanides filling (Yb, La, Eu, Pr, Ce).

CoSb3

CoLa0.5Sb3

0

75

150

225

300

20 30 40 50 60 70 80

Inte

nsi

ty(a.u.)

2 Theta (degree)

CoSb3

This work has a strong societal impact since it contributes to the

reduction/removal of major greenhouse gases, namely CO2, contributing to

alleviating global climate changes and contributing to the development of

more clean and efficient industrial processes, targeting the production of

value-added products (e.g. CH4) that can be used as fuel or fuel precursors.

New objectives includes the development of new nanoporous/nanofoams f-

block element based catalysts that can economical be competitive when

compared to the present state of art used by the industry.

0

500

1000

1500

2000

2500

20 30 40 50 60 70 80

Inte

nsi

ty (a.u.)

2 Theta (degree)

Cu12Sb4S13

0

300

600

900

1200

1500

1800

2100

20 30 40 50 60 70 80

Inte

nsi

ty(a

.u.)

2 Theta (degree)

Cu3SbS4

Cu12Sb4S13 (Tetrahedrite)• High symmetric crystal struture

(cubic) with a large unit cell.• Intrinsically low termal conductivity.• Existence as a mineral with

environmentally friendly and earthabundant elemento of sulfur.

Cu3SbS4 (Famatite)• Thermopower.• Potential p-type thermoelectric

material.

Chalcogenides

Intermetallic precursors

500nm

Nanofibers of bimetallic oxides

1 μm

Supported bimetallic oxides

Very active and selective nanostrutured bimetallic nickel-lanthanide or

actinide oxides to production of CH4. Yield to CH4 (LCH4/m2Ni.h) is significant

higher when compared to the reference catalysts.

Nanostrutured bimetallic nickel-lanthanide or actinide oxides present a

remarkable stability in the gaseous stream for at least 60 h, which was also

confirmed by the low carbon deposition measured after reaction (< 1 %).

The authors acknowledges the financial support under the projectUID/Multi/04349/2013

Stability of the bimetallic nickel-thorium

oxide in the gaseous stream.

0

20

40

60

80

100

0 20 40 60 80

Yie

ld &

Se

lect

ivit

y (%

)

t (h)

Yield CH4 Sel. CH4

350 oC

300 oC

350 oC 400 oC350 oC

250 oC

275 oC

Methanation of CO2 over bimetallic nickel-actinide oxides at 350 °C.

72

14 14

2

0

20

40

60

80

2NiO.ThO2 NiO/CeO2 2NiO.UO3 5%Rh/Al2O3

Yie

ld C

H4

(L/m

2N

i or

Rh

.h)

Catalyst

CH4 Selectivities > 98%

Thorium

Uranium(depleted)

Why not?

Research group1 QEf | f-element Chemistry Group2 ES | Solid State Group