Journal of Colloid and Interface Science 418 (2014) 193–199

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Journal of Colloid and Interface Science

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Catalytically active and hierarchically porous SAPO-11 zeolitesynthesized in the presence of polyhexamethylene biguanidine

0021-9797/$ - see front matter � 2013 Elsevier Inc. All rights reserved.http://dx.doi.org/10.1016/j.jcis.2013.11.065

⇑ Corresponding authors.E-mail addresses: mengxj@zju.edu.cn (X. Meng), fsxiao@zju.edu.cn (F.-S. Xiao).

Yan Liu a,d, Wei Qu b, Weiwei Chang a, Shuxiang Pan a, Zhijian Tian b, Xiangju Meng a,⇑, Marcello Rigutto c,Alexander van der Made c, Lan Zhao e, Xiaoming Zheng a, Feng-Shou Xiao a,⇑a Key Lab of Applied Chemistry of Zhejiang Province, Department of Chemistry, Zhejiang University (XiXi Campus), Hangzhou 310028, PR Chinab State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, PR Chinac Shell Technology Centre Amsterdam (STCA), CW-01-07, Grasweg 31, 1031 HW Amsterdam, The Netherlandsd Department of Chemical Engineering and Technology, East China Institute of Technology, Nanchang 330013, PR Chinae Advanced Membranes and Porous Materials Center, Chemical and Life Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal2955-6900, Saudi Arabia

a r t i c l e i n f o a b s t r a c t

Article history:Received 29 August 2013Accepted 24 November 2013Available online 3 December 2013

Keywords:Hierarchical zeoliteSAPO-11Supported platinum catalystHydroisomerizationn-Dodecane

Hierarchically porous SAPO-11 zeolite (H-SAPO-11) is rationally synthesized from a starting silicoalumi-nophosphate gel in the presence of polyhexamethylene biguanidine as a mesoscale template. The sampleis well characterized by XRD, N2 sorption, SEM, TEM, NMR, XPS, NH3-TPD, and TG techniques. The resultsshow that the sample obtained has good crystallinity, hierarchical porosity (mesopores at ca. 10 nm andmacropores at ca. 50–200 nm), high BET surface area (226 m2/g), large pore volume (0.25 cm3/g), andabundant medium and strong acidic sites (0.36 mmol/g). After loading Pt (0.5 wt.%) on H-SAPO-11 byusing wet impregnation method, catalytic hydroisomerization tests of n-dodecane show that the hierar-chical Pt/SAPO-11 zeolite exhibits high conversion of n-dodecane and enhanced selectivity for branchedproducts as well as reduced selectivity for cracking products, compared with conventional Pt/SAPO-11zeolite. This phenomenon is reasonably attributed to the presence of hierarchical porosity, which is favor-able for access of reactants on catalytically active sites. The improvement in catalytic performance inlong-chain paraffin hydroisomerization over Pt/SAPO-11-based catalyst is of great importance for itsindustrial applications in the future.

� 2013 Elsevier Inc. All rights reserved.

1. Introduction

Hierarchically porous zeolites with good mass transfer andexcellently catalytic properties have been attracted much attentiondue to the advantageous combination of both microporous zeolitesand mesoporous materials since the pioneer reports on synthesisof mesoporous zeolites using mesoscale soft templates such aspolymers [1–3], organosilanes [4–8], and surfactant micelles [9–12]. Notably, despite much encouraging progress for hierarchicallyporous aluminosilicate zeolites in recent years [13–15], the syn-theses of hierarchically porous silicoaluminophosphate zeolites(SAPOs) are still scarce yet [16–22].

Recently, silicoaluminophosphate zeolites play important rolesin industrial petrochemical processes [16–39]. For examples,SAPO-34 exhibits extremely high selectivities for ethylene andpropylene in methanol-to-olefins (MTO) [20–28]; Pt supportedon SAPO-11 (Pt/SAPO-11) shows high selectivity for branchedisomers with high viscosity indices and low pouring points in

hydroisomerization of long-chain n-paraffins (isodewaxing of lu-bricant oils) [29–39]. The enhancement of the branched isomersis very favorable for increasing the octane number of gasolineand improving the low-temperature fluidity of diesel or lubricantbase stocks. To increase catalytic activities, great efforts have beendevoted to synthesize hierarchical SAPO zeolites with good masstransfer [16–22]. Successful examples are to synthesize hierarchi-cally porous SAPO-11 zeolites from long-chain mesoscale tem-plates [17–19]. However, the applications of these hierarchicallyporous SAPO-11 zeolites are still limited remarkably, and one ofthe reasons is relatively high-cost of these soft mesoscale tem-plates used in the syntheses.

It is very interesting to note that low-cost and nontoxicguanidine and its derivatives as products of animal metabolismcould direct the crystallization of aluminophosphate-based zeo-lites [40–42]. Herein, we report a facile synthesis of hierarchicallyporous SAPO-11 zeolite from using low-cost and nontoxic polyhex-amethylene biguanidine (PHMB) as a mesoscale template. Veryimportantly, the hierarchically porous SAPO-11 supported Pt cata-lyst exhibits superior catalytic properties in hydroisomerization ofn-dodecane, compared with conventional SAPO-11.

5 10 15 20 25 30 35 40

233170440060

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Pore diameter (nm)

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0.4

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logD

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3 /g)

a

b

Fig. 1. (A) XRD patterns and (B) N2 sorption isotherms of (a) C-SAPO-11 and (b) H-SAPO-11 samples. Insert: pore size distribution curve.

Table 1Textural parameters for C-SAPO-11 and H-SAPO-11 samples.

Sample SBET (m2/g) SExt (m2/g) Vmeso (cm3/g) Vmicro (cm3/g)

C-SAPO-11 140 38 0.08 0.06H-SAPO-11 226 106 0.15 0.10

150 300 450 600 75086

88

90

92

94

96

98

100

b

Wei

ght (

%)

Temperature, oC

a

Fig. 2. TG curves of as-synthesized (a) C-SAPO-11 and (b) H-SAPO-11.

194 Y. Liu et al. / Journal of Colloid and Interface Science 418 (2014) 193–199

2. Experimental section

2.1. Materials

Polyhexamethylene biguanidine hydrochloride (PHMB,wt.20.6% in water, MW at �2500, PH = 5.27, q = 1.047) was sup-plied from Dasheng Technology Company in Shanxi (China), phos-phoric acid (H3PO4, wt.85%) was supplied from Shanghai ChemicalReagent Company (China), Pt(NH3)4Cl2 (wt.98%), di-n-propylamine(DPA), and fumed SiO2 were supplied from Aladdin Shanghai (Chi-na). Pseudoboehmite with purity of wt.70% was supplied from Sen-chi Fine Chemicals Company in Shandong (China).

2.2. Synthesis of conventional SAPO-11

Conventional SAPO-11 zeolite was hydrothermally synthesizedaccording to Refs. [32,43]. As a typical run, 1.96 mL H3PO4 (85%)was dissolved in 14 g distilled H2O under stirring, followed by addi-tion of 2.0 g pseudoboehmite. After stirring for 2 h, 2.4 mL DPA wasslowly added. After stirring for 2 h, 0.168 g fumed SiO2 was added.After stirring for 2 h, a gel with molar ratio of 0.2SiO2/Al2O3/P2O5/1.25DPA/55H2O was obtained, which was transferred into anautoclave for crystallization at 200 �C for 48 h. The as-synthesizedproduct was collected by filtration, dried in air, and calcined at600 �C for 6 h to remove the organic template. After ion-exchangewith 1 M NH4NO3 for 2 h at 80 �C and calcination at 450 �C for4 h (repeating for three times), the product of SAPO-11 was finallyobtained, which was designated as C-SAPO-11.

2.3. Synthesis of hierarchical SAPO-11

In a typical run, 2.0 g pseudoboehmite was dissolved in 11 gdistilled H2O under stirring, followed by addition of 1.96 mLphosphoric acid (H3PO4). After stirring for 2 h, 0.168 g of fumedsilica was added slowly. After stirring for 2 h, 2.3 mL DPA and0.25–0.50 g PHMB were added. After stirring for 2 h, a gel with mo-lar ratio of 0.2 SiO2/Al2O3/P2O5/1.2DPA/0.008–0.016PHMB/45H2Owas obtained, which was transferred into an autoclave for crystal-lization at 200 �C for 48 h. The as-synthesized product was filteredand washed with distilled water, dried in air, and calcined at 600 �Cfor 6 h to remove the organic template. After ion-exchange with1 M NH4NO3 for 2 h at 80 �C and calcination at 450 �C for 4 h(repeating for three times), the product of SAPO-11 was finally ob-tained, which was designated as H-SAPO-11.

2.4. Characterization

X-ray powder diffraction (XRD) patterns were measured with aRigaku X-ray diffractometer using Cu Ka (k = 1.54 Å) radiation.Scanning electron microscopy experiments were performed onHitachi SU-1510 electron microscopes. Transmission electronmicroscopy (TEM) experiments were performed on a JEM-3010electron microscope (JEOL, Japan) with an acceleration voltage of300 kV. High-resolution STEM imaging was conducted with 70 mC2 aperture, spot size 9, a high-angle annular dark-filed (HAADF)detector with inner detection angle larger than 76 mrad, and100 mm camera length to ensure Z-contrast. Under such condi-tions, a spatial resolution of 1.4 Å was obtained. The nitrogen sorp-tion isotherms at the temperature of liquid nitrogen weremeasured using Micromeritics ASAP 2020M system. Solid-stateNMR experiments were performed with magic angle spinning(MAS) on a JEOL JNM-A-400WB spectrometer operating at fre-quencies of 79.41, 104.17 and 161.83 MHz for 29Si, 27Al and 31P,respectively. Chemical shifts were referenced to 2,2-dimethyl-2-silapen-tane-5-sulfonate sodium salt (DSS) for 29Si, 1 mol/L of

Al(H2O)63+ for 27Al, and 85% H3PO4 for 31P. The sample was spun

at 4, 10, and 5.2 kHz for 29Si, 27Al, and 31P, respectively. Theacidity of the samples was determined using the stepwise

g

f

a b

d

e

c

Fig. 3. SEM images of (a–c) C-SAPO-11 and (d–f) H-SAPO-11 as well as (g) TEM image of H-SAPO-11.

Y. Liu et al. / Journal of Colloid and Interface Science 418 (2014) 193–199 195

temperature-programmed desorption of ammonia automatedchemisorption analysis unit (NH3-TPD) with a thermal conductiv-ity detector (TCD) under nitrogen flow. And the amount of acidicsites are normalized based on the area of the desorption peaks. APerkin-Elmer TGA 7 unit was used to carry out thermogravimetricanalysis (TGA) in air at a heating rate of 10 �C/min.

2.5. Catalyst preparation and catalytic hydroisomerization of n-dodecane

Pt (0.5 wt.%) was loaded on calcined C-SAPO-11 and H-SAPO-11 by wet impregnation method using Pt(NH3)4Cl2 as a Pt source.After drying at 120 �C for overnight and calcined at 450 �C for 3 h.The obtained samples were pressed into tablets with a diameter

of 12.7 mm, using a hand-operated press for 10 min. Then, theas-prepared tablets were crushed into particles with 20–40 meshsizes, which were designated as Pt/C-SAPO-11 and Pt/H-SAPO-11,respectively.

Prior to the hydroisomerization of n-dodecane reaction, the cat-alysts (ca. 10 mL, 20–40 mesh) were reduced in flowing hydrogen(ca. 120 ml/min) at 450 �C for 2 h. Hydroisomerization ofn-dodecane (n-C12) was carried out in a fixed-bed continuous reac-tor at 8.0 MPa pressure. The reaction conditions were H2/n-C12

(mol/mol) at 13, weight hourly space velocity (WHSV) at 1.0 h�1,and reaction temperature ranged from 250 to 350 �C. The reactantand the products were analyzed online by a gas chromatograph(Agilent 7890A), equipped with a flame ionization detector andan HP-5 (60 m � 0.32 mm) capillary column.

**

* a

b

*

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**

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1

Peak 1-Si (4Al)

Peak 2-Si (3Al, 1Si)

Peak 3-Si (2Al, 2Si)

Peak 4-Si (1Al, 3Si)

Peak 5-Si (4Si)

5

4

3

21

54

32

a

100 50 0 -50 -100 -150

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nsit

y (a

.u)

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nsit

y (a

.u)

Chemical shift (ppm)

-60 -80 -100 -120 -140

Inte

nsi

ty (

a.u)

Chemical shift (ppm)

Fig. 4. (A) 27Al, (B) 31P, and (C) 29Si MAS NMR spectra of calcined (a) C-SAPO-11 and(b) H-SAPO-11 samples. Asterisks (⁄) correspond to spinning side bands.

Table 2The Si species in C-SAPO-11 and H-SAPO-11 samples.

Sample Si(4Al)(%)

Si(3Al, 1Si)(%)

Si(2Al, 2Si)(%)

Si(Al, 3Si)(%)

Si(4Si)(%)

C-SAPO-11

15.6 8.9 40.2 28.8 6.5

H-SAPO-11

11.4 35.3 41.6 9.5 2.2

196 Y. Liu et al. / Journal of Colloid and Interface Science 418 (2014) 193–199

3. Results and discussion

The hierarchically mesoporous SAPO-11 zeolite was synthe-sized in the presence polyhexamethylene biguanidine (PHMB),which was designated as H-SAPO-11. In comparison, conventionalSAPO-11 was synthesized in the absence of PHMB, which was des-ignated as C-SAPO-11.

Fig. 1A shows XRD patterns of H-SAPO-11 and C-SAPO-11 sam-ples, giving typical peaks associated with AEL zeolite structure[44]. Fig. 1B shows N2 sorption isotherms of calcined H-SAPO-11and C-SAPO-11 samples. The N2 sorption isotherms are powerfultechniques to determine the sample porous structure, obtainingthe sample textural parameters such as BET surface area, pore vol-ume, and pore diameters. Notably, both H-SAPO-11 and C-SAPO-11samples show a steep increase occurring in the curve at a relativepressure of 10�6 < P/P0 < 0.01, which is due to the filling of microp-ores. In addition, at a relative pressure of 0.4–0.95, they appear ahysteresis loop, suggesting the presence of mesoporosity in thesesamples. Notably, the hysteresis loop of H-SAPO-11 is much stron-ger than that of C-SAPO-11, indicating that the mesoporosity ofH-SAPO-11 is much larger than that of C-SAPO-11. The BET surfacearea (226 m2/g) and external surface area (106 m2/g) as well aspore volume (0.25 cm3/g) of H-SAPO-11 are much higher thanthose (140 m2/g, 38 m2/g, and 0.14 cm3/g, respectively) ofC-SAPO-11 as presented in Table 1. The presence of larger mesopo-rosity in H-SAPO-11 than that in C-SAPO-11 is reasonably relatedto the contribution of PHMB as a mesoscale template in thesynthesis.

Fig. 2 shows TG curves of H-SAPO-11 and C-SAPO-11 samples.The weight loss below 200 �C corresponds to the removal of phys-ically adsorbed water, while the loss ranged from 200 to 650 �C ismainly due to decomposition of the organic templates [18,42].Notably, the amount (2.4 mL) of DPA used in the synthesis of C-SAPO-11 is a little higher than that (2.3 mL) of H-SAPO-11, butthe weight loss ranged at 200–650 �C for H-SAPO-11 is obviouslyhigher than that for C-SAPO-11. This phenomenon should be rea-sonably assigned to the presence of additional template of PHMBin the starting gels for synthesizing H-SAPO-11.

Fig. S1 shows dependence of PHMB/P2O5 ratios on the productsin the synthesis observed from XRD patterns. When PHMB/P2O5

ratios were ranged 0.008–0.016, hierarchical SAPO-11 zeolite prod-ucts could be obtained (Fig. S1b–d). When the ratio reached 0.018,a little amount of SAPO-41 appeared in the product as an impurity(Fig. S2). Therefore, the synthesis of H-SAPO-11 is only controllablein a narrow range by adjusting PHMB/P2O5 ratios. Fig. S3 shows N2

sorption isotherms of calcined H-SAPO-11 samples synthesized inthe presence of various amounts of PHMB, and their texturalparameters are presented in Table S1. The results indicate thatthe mesoporous surface area and pore volume of the samples pos-itively increase with the content of PHMB added in the startinggels, which confirm that the PHMB is mainly contributed to themesoporosity in the H-SAPO-11.

Furthermore, it is observed that the SiO2/P2O5 ratios stronglyinfluence the synthesis of H-SAPO-11, as shown in Fig. S4. Whenthis ratio is higher than 0.4 or less than 0.2, SAPO-31 as an impurityappeared in the products. Therefore, the suitable SiO2/P2O5 ratiosin the starting gels should be controlled in the range of 0.2–0.4.In addition, the other factors such as Al2O3/P2O5, DPA/P2O5, H2O/P2O5, crystallization temperature, and crystallization time alsoinfluence the synthesis of H-SAPO-11, as shown in Table S2 andFig. S5. Moreover, the crystallization temperature also influencesthe crystallization of SAPO-11. Lower temperatures always requirelonger crystallization time, while high temperatures easily form animpurity such as SAPO-31, as presented in Table S2. The resultsindicate that hierarchical SAPO-11 sample with a pure phase could

only be prepared in a narrow phase diagram of Al2O3–P2O5–SiO2–H2O–DPA–PHMB by a comprehensive consideration of thesefactors.

280 290 300 310 320 330 340

50

60

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b

a

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C12

isom

er s

elec

tivi

ty (

%)

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80

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er y

ield

(%

)

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C

280 290 300 310 320 330 34020

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80

90

100b

Tot

al C

12 C

onve

rsio

n (%

)

Temperature, oC

Aa

Temperature, oC

Y. Liu et al. / Journal of Colloid and Interface Science 418 (2014) 193–199 197

Fig. 3 shows scanning electron micrograph (SEM) images ofC-SAPO-11 (Fig. 3a–c) and H-SAPO-11 (Fig. 3d–f) as well as trans-mission electron micrograph (TEM) image of H-SAPO-11 (Fig. 3g).The sample SEM images show that both are spherical-like(Fig. 3a and d). However, the C-SAPO-11 particles (ca. 6 lm,Fig. 3b) are aggregated by cubic crystals (Fig. 3c), while theH-SAPO-11 particles (ca. 5 lm, Fig. 3e) are formed by burring crys-tals (Fig. 3f). The H-SAPO-11 particles have hierarchical porosity(macropores at ca. 50–200 nm and mesopores at ca. 10 nm,Fig. 3e–f). TEM image of H-SAPO-11 exhibits direct evidence thatthe sample has random mesoporosity (ca. 10 nm) and orderedmicropores (Fig. 3g), which is in good agreement with thoseobtained from N2 sorption isotherms (Fig. 1B-b).

Fig. 4 shows 27Al, 31P, and 29Si MAS NMR spectra of calcinedmesoporous H-SAPO-11 and C-SAPO-11. The 27Al MAS spectrashow a sharp resonance signal at 36 ppm assigned to tetrahedrallycoordinated aluminum ion bound via oxygen to four P atoms(Fig. 4A) [45–47]. In addition, a small downfield signal at ca.10 ppm is observed (Fig. 4A), which is probably due to octahedralcoordination of aluminum atoms [48,49]. The 31P MAS spectrashow one single sharp line at �29 ppm (Fig. 4B), associated withthe tetrahedral P sites neighboring AlO4 tetrahedral P(4Al) [32].These results suggest that Al and P have similar 4-coordinationenvironments in H-SAPO-11 and C-SAPO-11 samples.

In the 29Si MAS NMR spectra (Fig. 4C), C-SAPO-11 and H-SAPO-11 exhibit relatively broad signals ranged at �70 to �115 ppm.After deconvolution (rough estimation by using Gaussian curves,Fig. 4C), the samples give the signals at ca. 85, 92, 95, 100,110 ppm, as presented in Table 2. These assignments are in goodagreement with those of Si[(4 � x)Al, xSi] species in the zeoliteframework reported previously [32,33]. Notably, C-SAPO-11 is rel-atively rich Si(1Al, 3Si) species, while H-SAPO-11 has relatively

100 200 300 400 500 600 700

Am

mon

ia d

esor

bed

(a.u

)

Temperature, ºC

b

a

Fig. 5. NH3-TPD profiles of (a) C-SAPO-11 and (b) H-SAPO-11 samples.

Table 3Acidic concentration of C-SAPO-11 and H-SAPO-11 estimated from NH3-TPDtechnique.

Sample Acidity (mmol NH3/g solid)

Weak acid sites(100–250 �C)

Medium and strong acid sites(250–420 �C)

Totalamount

C- SAPO-11 0.41 0.300.71H- SAPO-11 0.37 0.360.73

280 290 300 310 320 330 34020

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)

b

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D

280 290 300 310 320 330 3400

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50

Cra

ckin

g S

elec

tivi

ty (

%)

E a

b

Temperature, oC

Temperature, oC

Temperature, oC

Fig. 6. Dependences of (A) conversion of n-dodecane, (B) C12 isomer selectivities;(C) C12 isomer yield, (D) percentage of di-branched isomers in total C12 isomers, and(E) cracking product selectivity on reaction temperature over (a) Pt/C-SAPO-11 and(b) Pt/H-SAPO-11 catalysts.

198 Y. Liu et al. / Journal of Colloid and Interface Science 418 (2014) 193–199

high Si(3Al, 1Si) species. These results suggest that the PHMB ben-efits for the dispersion of Si domain in the SAPO-11 framework.

Fig. 5 shows the temperature-programmed desorption ofammonia (NH3-TPD) curves of H-SAPO-11 and C-SAPO-11. Theyexhibit two peaks at 140–270 �C and 300–500 �C, which are as-signed to relatively weak and strong acidic sites in the samples[32]. Notably, total acidic sites of H-SAPO-11 and C-SAPO-11 aresimilar, but H-SAPO-11 has a little higher concentration of strongacidic sites (Table 3). This phenomenon might be related to the dif-ference for the dispersion of Si–O–Si domains in the samples syn-thesized in the absence or presence of PHMB template.

H-SAPO-11 supported Pt catalyst (0.5 wt.%) was performedfrom wet impregnation of Pt(NH3)4Cl2 with H-SAPO-11. In compar-ison, C-SAPO-11 supported Pt catalyst was also prepared with thesame Pt loading. Fig. 6 shows catalytic data in hydroisomerizationof n-dodecane over Pt/H-SAPO-11 and Pt/C-SAPO-11 catalysts. Inthis reaction, the products are mainly mono-branched isomers,di-branched isomers, and cracking hydrocarbons of C4–C6. Withthe increasing temperature, both the conversion of n-dodecaneand the selectivities for di-branched isomers as well as crackingproducts significantly enhanced. As a result, the catalysts exhibitthe maxima isomer yield. Pt/C-SAPO-11 catalyst gives the isomeryield of 64.2% at 315 �C, while Pt/H-SAPO-11 catalyst shows theisomer yield of 75.0% at 322 �C. In addition, not only for the conver-sion but also for the isomer selectivities of Pt/H-SAPO-11 catalyst isalso much higher than that of Pt/C-SAPO-11 catalyst. However, Pt/H-SAPO-11 catalyst exhibits much lower selectivity for the crack-ing products. These results indicate that Pt/H-SAPO-11 catalystshows much better catalytic performance in catalytic hydroiso-merization of n-dodecane than Pt/C-SAPO-11 catalyst.

To compare the Pt/H-SAPO-11 with Pt/C-SAPO-11 catalyst, thePt nanoparticles on the H-SAPO-11 and C-SAPO-11 supports areinvestigated by scanning transmission electron micrograph (STEM)technique, as shown in Fig. S6. The results indicate that the Ptnanoparticles have very similar dispersion on the H-SAPO-11 andC-SAPO-11 supports, which suggests that the catalytic differencein the hydroisomerization over Pt/H-SAPO-11 with Pt/C-SAPO-11catalyst is not related to the dispersion of Pt nanoparticles on thesupports.

Considering similar acidic sites and the same chemical compo-sition as well as very similar Pt nanoparticles for H-SAPO-11 andC-SAPO-11, much higher catalytic performance in isomerizationof n-dodecane over Pt/H-SAPO-11 than that over Pt/C-SAPO-11 isreasonably assigned to the contribution of hierarchical porosityin the H-SAPO-11, which is very favorable for the diffusion of reac-tant of n-dodecane and reaction intermediate of mono-branchedisomers, giving relatively high yields of mono-branched and di-branched isomers under the same reaction conditions. In contrast,C-SAPO-11 support has relatively long microporous channels,which strongly limits the diffusion of the n-dodecane and mono-branched isomers, giving relatively high selectivity of crackingproducts.

4. Conclusion

A hierarchical SAPO-11 zeolite (H-SAPO-11) has been success-fully synthesized in the presence of low-cost and commercialPHMB template in the starting gel. After loading Pt nanoparticles,Pt/H-SAPO-11 catalyst exhibits higher activity, better isomer selec-tivity, and lower cracking product selectivity in n-dodecane hydro-isomerization than Pt nanoparticles supported on conventionalSAPO-11 zeolite does, which is directly attributed to the presenceof hierarchical porosity in the H-SAPO-11. The superior catalyticproperties of Pt/H-SAPO-11 catalyst are potentially important for

industrial applications of the long-chain paraffin hydroisomeriza-tion in the future.

Acknowledgments

This work was supported by the Natural National Science Foun-dation of China (21273197and U1162201), National High-Tech Re-search & Development Program of China (2013AA065301), andFundamental Research Funds for the Central Universities(2013XZZX001).

Appendix A. Supplementary material

Supplementary data associated with this article can be found, inthe online version, at http://dx.doi.org/10.1016/j.jcis.2013.11.065.

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