Mesocellular Silica Composite

May 27, 2014 - After that, the solution was heated in a water bath at 40 °C, then hydrochloric ...... New Catalysts of Hydrogenation of Phenylacetyle...
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Reactivity of Ni−Carbon Nanofibers/Mesocellular Silica Composite Catalyst for Phenylacetylene Hydrogenation Waleeporn Donphai,†,‡ Takashi Kamegawa,‡,§ Metta Chareonpanich,*,†,∥ and Hiromi Yamashita*,‡,§ †

Department of Chemical Engineering, Faculty of Engineering, and ∥Center of Nanotechnology, Kasetsart University, Bangkok 10900, Thailand ‡ Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan § Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, Katsura, Kyoto 615-8520, Japan ABSTRACT: In this research, a novel composite catalyst, Ni-carbon nanofibers (CNFs) supported on mesocellular silica (MS), has been successfully prepared with an attempt to improve the activity in liquid-phase phenylacetylene hydrogenation. Consequently, the MS support was prepared by modifying the pore size of SBA-15 mesoporous silica using a swelling agent, 1,3,5-trimethylbenzene (TMB). After that, nickel nanoparticles were loaded onto the MS support via an impregnation method, and CNFs were consecutively synthesized using nickel nanoparticles on the MS support as the catalyst in the catalytic chemical vapor deposition (CCVD) process. The obtained Ni−CNFs/MS catalyst with unique composite structure consisting of nickel active metals on the tips of CNFs was examined for its hydrophobicity and activity. It was found that the composite catalysts with CNFs synthesis times of 1 and 3 h (Ni−CNFs(1)/MS and Ni−CNFs(3)/MS) had a relative hydrophobicity of approximately 1.1 and 1.5 times higher than that without CNFs, respectively. Moreover, the turnover frequency (TOF) of Ni−CNFs/MS catalyst was also significantly increased with increasing the amount of Ni−CNFs composites on the MS support. Accordingly, Ni−CNFs(3)/MS catalyst exhibited the highest TOF (4.32 s−1); which was approximately 3.2 times higher than that of Ni/MS catalyst due to the hydrophobic surface property of CNFs and unique composite structure of Ni−CNFs/MS catalyst.

1. INTRODUCTION Phenylacetylene, a hazardous impurity in styrene feedstock, plays a role in the poisoning of polymerization catalysts; accordingly, a maximum acceptable limit of not more than 10 ppm is required.1−6 With an attempt to eliminate certain amounts of phenylacetylene in the petrochemical industry, selective phenylacetylene hydrogenation to styrene product has been applied.1−8 Noble transition metals such as Pd, Pt, Ru, and Rh have been used as the catalyst in phenylacetylene hydrogenation.1,3−11 Among them, Pd loaded on different kinds of supports, i.e., silica, carbon, and alumina,1,3,6,9,12 were reported to give relatively high phenylacetylene conversion in a range of 50− 60% under mild conditions (50 °C, 1 atm for 3 h).3,9,12 However, the availability and cost are still a main limitation of the group of noble metals. Therefore, nickel (Ni), a non-noble transition metal, is considered in place of the noble metals as a promising catalyst in the hydrogenation reaction due to its low cost, availability, and high performance.13−17 In addition, carbon nanofibers (CNFs) are also attractive as a catalyst support because of their unique surface properties including resistance to strong acid and base, hydrophobic surface property, and better hydrogen diffusion on carbon-grain boundary, leading to better catalyst performance.11,18−21 Accordingly, many researchers have focused on catalytic hydrogenation over Ni metal loaded on the CNFs modified by an acid treatment, which results in high Ni metal dispersion on the CNFs surface and strong metal−support interaction.22−25 However, drawbacks to the reaction involving relatively larger reactant and products are the small pore © 2014 American Chemical Society

diameter of CNFs and metal deposited inside the CNFs pore which could decrease mass transfer during hydrogenation.22 Because hydrogenation of phenylacetylene is carried out in a liquid-phase system, the reaction limitations caused by reactant diffusion and adsorption are major problems for the conventional catalysts.1,12 To overcome the limitation of reactant mass transfer and at the same time enhance the adsorption capacity of organic reactant during the reaction on catalyst surface, the novel Ni−CNFs composites with unique composite structure containing Ni nanocluster on the tip of carbon nanofibers over mesocellular silica (MS) support have been applied as the catalyst. In this work, Ni−CNFs composites on MS support (Ni− CNFs/MS catalysts) were prepared on the Ni/MS catalysts by using the catalytic chemical vapor deposition (CCVD) technique via a tip-growth mechanism.26−28 The properties of catalysts were characterized by using the nitrogen adsorption technique, X-ray diffraction spectroscopy, thermogravimetric analysis, Raman spectroscopy, transmission electron microscopy, water adsorption, and CO adsorption. The performance of catalysts in the liquid-phase phenylacetylene hydrogenation was examined and compared to that of Ni/MS catalysts. The outstanding reactivity in terms of turnover frequency (TOF) and relative hydrophobicity attributed to their unique composite structure has been reported and discussed. Received: Revised: Accepted: Published: 10105

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2. EXPERIMENTAL SECTION 2.1. Preparation of Ni−CNFs Composite Catalyst. 2.1.1. Mesocellular Silica Support Preparation. Mesocellular silica (MS) support was prepared by modified synthesis method of SBA-15 mesoporous silica using Pluronic P123 (P123: EO20PO70EO20, Aldrich) as a mesopore template and 1,3,5trimethylbenzene (TMB) as a swelling agent of mesopore. The molar ratios of chemicals were as follows: 1 SiO2:0.088 Pluronic P123:4 HCl:200 H2O.29,30 Pluronic P123 was dissolved with distilled water under stirring at room temperature and sodium silicate was slowly dropped into the solution. After that, the solution was heated in a water bath at 40 °C, then hydrochloric acid (37 wt % concn) and TMB (TMB:Pluronic P123 = 1:2 g/ g) were sequentially added into the solution under stirring, and stirring continued for 24 h. In the hydrothermal treatment process, the mixture was aged in an autoclave at 100 °C for 24 h. The obtained product was filtered, washed with distilled water, dried at 100 °C overnight, and calcined in air at 550 °C for 6 h. 2.1.2. Nickel Catalyst Preparation. Nickel (Ni) of 10 wt % was loaded on MS support by using nickel(II) acetate as a nickel precursor via the incipient wetness impregnation method. MS support was added into the aqueous solution of nickel(II) acetate, and then the mixture was stirred at room temperature for 1 h. After that, water was evaporated under vacuum at 80 °C for 1 h, and then the obtained product was dried at 100 °C for 2 h. The solid product was calcined in air at 550 °C for 4 h. Prior to the synthesis of CNFs and catalytic reaction test, the obtained solid product was reduced by hydrogen under each condition. The activated sample was denoted as Ni/MS catalyst. 2.1.3. Carbon Nanofibers Synthesis. Carbon nanofibers (CNFs) composite with nickel on MS support was synthesized via CCVD method by using methane as a carbon source. CNFs synthesis was operated at 500 °C with different synthesis time periods (1 and 3 h). First, Ni/MS catalyst was activated by a hydrogen reduction process at 500 °C for 1 h. After that the feed gas was switched to nitrogen gas (100 mL/min) to remove excess hydrogen gas for 30 min. Then, methane gas (50 mL/ min) was continuously introduced into the reactor for 1 and 3 h. After the control period, the reactor was cooled down to room temperature. The samples obtained after the synthesis of CNFs on Ni/MS were denoted as Ni−CNFs(1)/MS and Ni− CNFs(3)/MS catalysts, respectively. 2.2. Catalyst Characterization. The textural properties of catalyst was analyzed by using the nitrogen adsorption− desorption technique (BEL-SORP max) at −196 °C after pretreatment under vacuum at 200 °C for 2 h. The specific surface area was calculated by using Brunauer−Emmett−Teller (BET) method in the relative pressure (P/P0) range of 0.05− 0.3. Pore size distribution was estimated by using Barrett− Joyner−Halenda (BJH) methods. Total pore volume was determined from the amount of N2 adsorbed at a P/P0 of 0.99. X-ray diffraction (XRD) analysis was performed by using the Rigaku Ultima IV X-ray diffractometer with Cu Kα radiation. The amount of carbon on the composite catalyst was calculated using the result from thermogravimetric analysis (TG-DTA 2000S, MAC Science Co., Ltd.) obtained in the temperature range from room temperature to 800 °C at a heating rate of 10 °C/min under air flow (50 mL/min). The crystallinities of carbon nanofibers on composite catalysts were analyzed by using Raman spectroscopy (JASCO NRS-3100) with a laser

wavelength of 532 nm. The morphology of catalysts was observed by using transmission electron microscopy (TEM, Hitashi HT7700). After the catalyst pretreatment under H2 flow at 500 °C for 1 h, the amount of active atoms on the nickel metal cluster was determined by using CO adsorption measurement (BEL-METAL-1, BEL Japan, Inc.) at 50 °C. 2.3. Catalyst Performance of Phenylacetylene Hydrogenation. The catalytic activity of Ni/MS, Ni−CNFs(1)/MS and Ni−CNFs(3)/MS catalysts in liquid-phase hydrogenation of phenylacetylene (PA) was examined. In this series of experiments, the catalyst (20 mg) was placed in a semibatch glass reactor fitted with a reflux condenser, and reduced with hydrogen gas at 450 °C for 1 h prior to reaction. The mixture of reactants (PA, 0.174 g; 2-propanol, 5 mL; and biphenyl (internal standard), 0.077 g) was introduced into the glass reactor under magnetic stirring at 80 °C in oil bath. After that, hydrogen gas (5 mL/min) was continuously fed into the mixture. The remaining reactant (PA) and the reaction products (styrene and ethylbenzene) were analyzed by a Shimadzu GC-2014 gas chromatograph using a flame ionization detector (FID) equipped with an Rtx-5 capillary column (5% phenyl and 95% dimethyl polysiloxane).

3. RESULTS AND DISCUSSION 3.1. Properties of Ni/MS and Ni−CNFs/MS Composite Catalysts. N2 adsorption−desorption isotherms of mesocellular silica (MS) support, Ni/MS, and Ni−CNFs/MS composites with different CNFs synthesis time periods are shown in Figure 1A. All the samples show a type IV isotherm

Figure 1. (A) Nitrogen adsorption−desorption isotherm and (B) pore size distribution of mesoporous silica support and catalysts (a) MS, (b) 10Ni/MS, (c) 10Ni−CNFs(1)/MS, and (d) 10Ni−CNFs(3)/MS.

with H2 hysteresis loop, indicating the existence of mesopore structure. This result indicated that nickel metal and CNFs did not affect the structure of MS support. Compared to that of SBA-15 with pore diameter of approximately 7 nm synthesized following our previous work,29 MS support exhibited relatively larger pore diameter in the range of 15−35 nm, resulting from pore expansion of SBA-15 by TMB as a swelling agent (Figure 1B). Moreover, it was found that all the catalysts revealed the similar range of pore diameter to that of the MS support. However, the peak intensity was consecutively decreased after nickel loading and the increases of CNFs synthesis time periods. Moreover, specific surface area and total pore volume of catalysts are shown in Table 1. MS support shows the highest specific surface area and pore volume of 535 m2/g and 1.36 cm3/g, respectively. After nickel loading onto the MS 10106

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significantly changed when increasing CNFs synthesis time period. The amounts of CNFs on the catalysts were calculated by using the data from thermogravimetric analysis (TGA), as shown in Figure 3A. The weight loss below 400 °C was attributed to moisture content in the catalyst, while weight loss in the temperature range of 400−570 °C indicated the decomposition of CNFs,28,37 which was used to calculate CNFs contents on the catalysts (Table 2). On the basis of the weight losses at 570 °C compared to the initial weight at 400 °C, the amounts of CNFs on Ni−CNFs(1)/MS and Ni− CNFs(3)/MS catalysts were determined (13.4 and 54.5 wt %, respectively). To evaluate the crystallinities of CNFs on the composite catalysts obtained from different CNFs synthesis time periods, Raman spectroscopy was applied and the results are shown in Figure 3B. The D-band around 1340 cm−1 corresponds to disorder and defect of carbon structure, and the existence of amorphous carbon38−40 in the G-band around 1570 cm−1 was attributed to graphitic carbon.38−40 It was found that the relative intensity between the D band and the G band of Ni− CNFs(1)/MS catalyst was quite similar to that of Ni− CNFs(3)/MS catalyst, showing that the characteristics of CNFs did not change when CNFs synthesis time periods were increased. TEM measurement was carried out to observe the morphology and structure of Ni−CNFs composite catalysts (Figure 4 panels a and b). It was found that the similar structures of Ni−CNFs/MS composite catalysts with different synthesis time periods were observed. CNFs with different diameters were grown from the surface MS support and continuously lifted up nickel metal clusters from the support following the tip-growth mechanism of CNFs synthesis.26−28 In this case, during the CNFs synthesis, methane gas was cracked over nickel active metals. Then the carbon radicals formed in this stage were consequently transferred to the active interface between nickel and mesocellular silica support where the formation of CNFs originated.26−28 This result was similar to the mechanism reported in our previous work.30 The surface hydrophobicity of catalysts was evaluated by using water adsorption technique at 298 K. The relative amount of adsorbed water was calculated from the amount of water adsorbed at P/P0 = 0.5 (Table 2). The relative amount of adsorbed water was 0.40 cm3/m2 for Ni/MS catalyst, while it was 0.27 cm3/m2 for Ni−CNFs(3)/MS catalyst. The amount of water adsorbed was decreased after modification of Ni/MS by CNFs, showing the clear effect of CNFs modification on the

Table 1. BET Surface Area, Pore Volume, and Average Nickel Metal Size of Catalysts

a

catalysts

BET surface area (m2/g)

pore volume (cm3/g)

Ni metal sizea (nm)

MS Ni/MS Ni−CNFs(1)/MS Ni−CNFs(3)/MS

535 299 264 194

1.36 1.13 0.96 0.67

19.3 26.3 24.5

Calculated from Scherrer equation.

support, the specific surface area was significantly decreased due to the blockage of nickel particles in the MS pores. In the case of Ni−CNFs composite catalyst, it was found that the specific surface area and pore volume were also decreased because of the growth of CNFs inside and over the surface of MS support. Figure 2 shows XRD patterns of fresh catalysts without and with CNFs. The diffraction patterns at 2θ of 44° and 52°

Figure 2. XRD patterns of fresh catalysts after reduction with H2 gas at 500 °C: (a) 10Ni/MS, (b) 10Ni−CNFs(1)/MS, (c) 10Ni−CNFs(3)/ MS.

observed in all catalyst samples (Ni/MS (after reduced in H2), Ni−CNFs(1)/MS, and Ni−CNFs(3)/MS) correspond to metallic nickel (111) and (200).31−35 In addition, the diffraction peak of graphitic carbon (002) at 2θ of 25°31,33,36 was observed in the Ni−CNFs composite catalysts. Moreover, the particle size of nickel metal on the catalyst support was calculated by using the Scherer equation, as shown in Table 1. Nickel metal size was increased after CNFs synthesis due to the aggregation of metal clusters during the CCVD process caused by relatively high synthesis temperature (500 °C). However, in the case of Ni−CNFs/MS catalyst, nickel metal size was not

Figure 3. (A) Weight loss and (B) Raman spectra of fresh catalysts: (a) 10Ni−CNFs(1)/MS, (b) 10Ni−CNFs(3)/MS. 10107

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Table 2. Amount of Carbon, Hydrophobicity, Product Selectivities, and Turnover Frequency (TOF) of Catalysts in Phenylacetylene Hydrogenation selectivityb (%) catalysts

amount of carbon (%)

amount of adsorbed water (cm3/m2)

hydrophobicitya

S

EB

Ni active atom ×1018 (atoms)

TOFc (s−1)

Ni/MS Ni−CNFs(1)/MS Ni−CNFs(3)/MS

13.4 54.5

0.40 0.38 0.27

1.0 1.1 1.5

89.6 91.8 91.6

10.4 8.2 8.4

6.14 4.23 1.42

1.36 2.03 4.32

a c

Calculated as a ratio of reverse proportion of amount of adsorbed water based on that of 10Ni/MS catalyst. bCalculated at 60% of PA conversion. Calculated from TOF = (% conversion × mole of reactant)/(time × mole of active Ni at surface).

Figure 4. TEM images of fresh catalysts. Inset: the overview of composite catalyst. (a) Ni−CNFs(1)/MS and (b) Ni−CNFs(3)/MS.

improvement of surface hydrophobicity. This result indicated that the hydrophobicity of Ni−CNFs(3)/MS was approximately 1.5 times higher than that of the catalyst without CNFs (Table 2). According to characterization results, it could be implied that the structural and textural property of Ni−CNFs/MS composite catalyst were not changed even though the synthesis time period was further increased. However, the surface hydrophobicity of composite catalyst was also enhanced with increasing synthesis time period. 3.2. Performance of Ni−CNFs/MS Catalysts on Phenylacetylene Hydrogenation. The performance of Ni−CNFs composite catalysts was investigated through liquid-phase phenylacetylene hydrogenation under atmospheric pressure of hydrogen in the semibatch glass reactor for 3 h. Phenylacetylene was hydrogenated to styrene and consecutively converted to ethylbenzene as a byproduct. Phenylacetylene conversions of Ni−CNFs composite catalysts (Ni−CNFs(1)/ MS and Ni−CNFs(3)/MS) were compared with that of Ni/ MS catalyst, as shown in Figure 5a−c. By increasing reaction time, phenylacetylene conversions of all catalysts were increased. It was found that Ni−CNFs(1)/MS composite catalyst exhibited the highest phenylacetylene conversion (90.8%), while Ni−CNFs(3)/MS composite catalyst gave the lowest conversion (64.8%). Comparing the catalyst performances between Ni−CNFs composite and Ni/MS catalysts, phenylacetylene conversion over Ni−CNFs(1)/MS was divided by phenylacetylene conversion over Ni/MS catalyst at 3 h time on stream (Figure 5a,b). The result indicated that Ni− CNFs(1)/MS composite catalyst had 1.03 times higher conversion than the Ni/MS catalyst. With increasing CNFs synthesis time period, phenylacetylene conversion was decreased because of its lower amount of active nickel on composite catalyst, resulting by the surface coverage of active

Figure 5. Reaction time profile of phenylacethylene hydrogenation with different catalysts: (a) Ni/MS, (b) Ni−CNFs(1)/MS, and (c) Ni−CNFs(3)/MS. (◆) PA conversion, (△) S yield, and (○) EB yield.

nickel metals by CNFs formation based on tip-growth mechanism. 10108

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phenylacetylene hydrogenation. The higher was the number of composite fibers between nickel metal cluster and CNF, the better activity due to the catalyst structure was observed. On the basis of the TOF, hydrophobicity, and effect of catalyst structure, the schemes of the surface reaction of phenylacetylene hydrogenation over Ni/MS and Ni−CNFs/ MS catalysts were proposed (Figure 6). It should be noted that

Furthermore, considering yields and product selectivities, Ni−CNFs composite catalysts gave higher styrene yield (the main product of phenylacetylene hydrogenation) than that of Ni/MS catalyst (Figure 5). The styrene selectivities of Ni/MS, Ni−CNFs(1)/MS, and Ni−CNFs(3)/MS catalysts were 89.6, 91.8, and 91.6%, respectively, at the same conversion of PA (60%) (Table 2). It was found that Ni−CNFs composite catalysts also provided higher styrene selectivity compared to that of Ni/MS catalyst due to the effect of surface hydrophobicity during the adsorption of phenylacetylene before the surface hydrogenation reaction. It should be noted that the amount of active nickel metal atoms evaluated from CO chemisorption data (stoichiometric value of CO: Ni equals to 2 for CO adsorption analysis) (Table 2) of Ni/MS catalyst was the highest, whereas it became lower with Ni−CNFs(1)/MS and Ni−CNFs(3)/MS catalysts, consecutively. After catalyst modification with CNFs by using CCVD method following the tip-growth mechanism, the amount of active nickel metal atoms was obviously decreased by approximately 1.4 times for Ni−CNFs(1)/MS, and 4.3 times for Ni−CNFs(3)/MS catalysts compared to that of Ni/ MS catalyst. This could be attributed to the fact that CNFs formed as the tip-growth mechanism partially covered the active nickel metal atoms. Moreover, this result implied that the longer was the CCVD period, the greater numbers of fibers of Ni−CNFs catalysts were formed until the CNFs-free active nickel clusters were all transformed into the composite fibers; the amount of active nickel metal atoms was then not changed. To compare the catalytic activity based on amounts of active nickel metal atoms exposed to reactants, turnover frequencies (TOF) were calculated as shown in Table 2. The TOF value after 3 h time on stream of Ni−CNFs(3)/MS catalyst was the highest among all catalysts as it was approximately 3.2 and 1.5 times higher than those of Ni/MS and Ni−CNFs(1)/MS catalysts, respectively. This result strongly confirmed that Ni− CNFs composite could enhance the catalytic activity in phenylacetylene hydrogenation due to better surface hydrophobicity and unique composite structure (a single nickel metal cluster on the tip of a single CNF). 3.3. Proposed Surface Reaction of Phenylacetylene Hydrogenation over Ni/MS and Ni−CNFs/MS Catalysts. Because catalytic activity in phenylacetylene hydrogenation could be improved by increasing the surface hydrophobicity of the catalysts (amounts of CNFs), leading to better adsorption ability of organic reactants during the reaction, it therefore simultaneously promoted the catalytic activity in phenylacetylene hydrogenation as the step next to surface adsorption.41,42 Moreover, since the Ni−CNFs composite catalyst consists of CNFs containing nickel metal clusters on their individual tips formed over MS support, the structure could therefore potentially overcome the limitation of reactant diffusion to active nickel atoms in order to react and convert to the product in the liquid phase reaction. To identify a degree of effect due to structure of Ni−CNFs composite catalyst on the catalytic activity while excluding the effect due to surface hydrophobicity, the TOF value of each catalyst was divided by its hydrophobicity value, and this value was defined as the structure−activity factor. It was found that the structure−activity factor of Ni−CNFs(1)/MS and Ni− CNFs(3)/MS catalysts were 1.4 and 2.1 times higher than that of Ni/MS catalyst, respectively. This indicated that besides the effect of surface hydrophobicity, the catalyst structure also played a significant role in promoting the activity in

Figure 6. Proposed scheme of selective hydrogenation of phenylacetylene to styrene on active nickel. Inset: TEM images of (A) Ni/ MS and (B) Ni−CNFs/MS catalysts.

the major difference in structural characteristics between Ni/ MS and Ni−CNFs/MS catalysts was the position of the active nickel atoms. With Ni/MS catalyst, nickel metal clusters were mainly dispersed in the inner cavities of MS supports (inset of Figure 6A). Consequently, the steric hindrance was potentially found in the case of Ni/MS catalyst because of the limited space over the nickel metal clusters inside the catalyst support (Figure 6A). On the contrary, in the case of the Ni−CNFs/MS catalyst, nickel metal clusters were transformed to Ni−CNF composites via the CCVD technique and simultaneously lifted up from the MS support. As a result, the unique structure of an individual CNF with a nickel metal cluster on its tip, spread away from the support, was observed (inset of Figure 6B). Therefore, more phenylacetylene molecules could be adsorbed and reacted to styrene product over Ni−CNFs/MS catalyst than over Ni/MS catalyst, based on the same amount of nickel metal clusters (Figure 6B).

4. CONCLUSIONS The composite catalysts between nickel and carbon nanofibers (CNFs) on mesocellular silica (MS) were successfully synthesized and applied for liquid-phase hydrogenation of phenylacetylene. It was found that with the catalyst modification as the Ni metal clusters on the tips of CNFs, the higher catalytic performance of Ni−CNFs/MS catalyst was increased compared to that of Ni/MS catalyst. This was attributed to the higher surface hydrophobicity and the unique structure with Ni clusters on tips of Ni−CNFs/MS catalyst formed by the tip-growth mechanism of CNFs synthesis. Accordingly, Ni−CNFs/MS catalysts exhibited higher adsorption capacity of organic compounds and less limited space (lower steric hindrance) for surface reaction compared to Ni/ MS catalysts. 10109

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Properties on the Liquid-Phase Selective Hydrogenation of Phenylacetylene on Supported Nickel Catalysts. Catal. Lett. 1998, 52, 205. (14) Relvas, J.; Andrade, R.; Freire, F. G.; Lemos, F.; Araujo, P.; Pinho, M. J.; Nunes, C. P.; Ribeiro, F. R. Liquid Phase Hydrogenation of Nitrobenzene over an Industrial Ni/SiO2 Supported Catalyst. Catal. Today 2008, 133−135, 828. (15) Hu, S.; Xue, M.; Chen, H.; Shen, J. The Effect of Surface Acidic and Basic Properties on the Hydrogenation of Aromatic Rings over the Supported Nickel Catalysts. Chem. Eng. J. 2010, 162, 371. (16) Chen, X.; Li, M.; Guan, J.; Wang, X.; Williams, C. T.; Liang, C. Nickel−Silicon Intermetallics with Enhanced Selectivity in Hydrogenation Reactions of Cinnamaldehyde and Phenylacetylene. Ind. Eng. Chem. Res. 2012, 51, 3604. (17) Erokhin, A. V.; Lokteva, E. S.; Golubina, E. V.; Maslakov, K. I.; Yermakov, A. Ye.; Uimin, M. A.; Lunin, V. V. Nickel-Supported Metal−Carbon Nanocomposites: New Catalysts of Hydrogenation of Phenylacetylene. Russ. J. Phys. Chem. A 2014, 88, 12. (18) Nhut, J. M.; Pesant, L.; Tessonnier, J. P.; Wine, G.; Guille, J.; Pham-Huu, C.; Ledoux, M. J. Mesoporous Carbon Nanotubes for Use as Support in Catalysis and as Nanosized Reactors for OneDimensional Inorganic Material Synthesis. Appl. Catal., A 2003, 254, 345. (19) Li, Y.; Li, Z. G.; Zhou, R. X. Bimetallic Pt-Co Catalysis on Carbon Nanotubes for the Selective hydrogenation of Cinnamaldehyde to Cinnamyl Alcohol: Preparation and Characterization. J. Mol. Catal. A: Chem. 2008, 279, 140. (20) Asedegbega-Nieto, E.; Bachiller-Baeza, B.; Kuvshinov, D.G.; Garcia-Garcia, F. R.; Chukanov, E.; Kuvshinov, G. G.; Guerrero-Ruiz, A.; Rodriguez-Ramos, I. Effect of the Carbon Support Nano-Structures on the Performance of Ru Catalysts in the Hydrogenation of Paracetamol. Carbon 2008, 46, 1046. (21) Jahjah, M.; Kihn, Y.; Teuma, E.; Gomez, M. Ruthenium Nanoparticles Supported on Multi-walled Carbon Nanotubes: Highly Effective Catalytic System for Hydrogenation Processes. J. Mol. Catal. A: Chem. 2010, 332, 106. (22) Pham-Huu, C.; Keller, N.; Ehret, G.; Charbonniere, L. J.; Ziessel, R.; Ledoux, M. J. Carbon Nanofiber Supported Palladium Catalyst for Liquid-Phase Reactions an Active and Selective Catalyst for Hydrogenation of Cinnamaldehyde into Hydrocinnamaldehyde. J. Mol. Catal. A: Chem. 2001, 170, 155. (23) Toebes, M. L.; Nijhuis, T. A.; Hajek, J.; Bitter, J. H.; Dillen, A. J. van; Murzin, D. Y.; Jong, K. P. de Support Effects in Hydrogenation of Cinnamaldehyde over Carbon Nanofiber-Supported Platinum Catalysts: Kinetic Modeling. Chem. Eng. Sci. 2005, 60, 5682. (24) Wang, H.; Zhao, F.; Fujita, S. I.; Arai, M. Hydrogenation of Phenol in scCO2 over Carbon Nanofiber Supported Rh Catalyst. Catal. Commun. 2008, 9, 362. (25) Wang, C.; Qiu, J.; Liang, C.; Xing, L.; Yang, X. Carbon Nanofiber Supported Ni Catalysts for the Hydrogenation of Chloronitrobenzenes. Catal. Commun. 2008, 9, 1749. (26) Jong, K. P. de; Geus, J. W. Carbon Nanofibers: Catalytic Synthesis and Applications. Catal. Rev. Sci. Eng. 2000, 42, 481. (27) Abild-Pedersen, F.; Norskov, J. K. Mechanisms for Catalytic Carbon Nanofiber Growth Studied by ab Initio Density Functional Theory Calculations. Phys. Rev. B 2006, 73 (115419), 1. (28) Dussault, L.; Dupin, J. C.; Guimon, C.; Monthioux, M.; Latorre, N.; Ubieto, T.; Romeo, E.; Royo, C.; Monzon, A. Development of Ni− Cu−Mg−Al Catalysts for the Synthesis of Carbon Nanofibers by Catalytic Decomposition of Methane. J. Catal. 2007, 251, 223. (29) Chareonpanich, M.; Nanta-ngern, A.; Limtrakul, J. Short-Period Synthesis of Ordered Mesoporous Silica SBA-15 Using Ultrasonic Technique. Mater. Lett. 2007, 61, 5153. (30) Donphai, W.; Faungnawakij, K.; Chareonpanich, M.; Limtrakul, J. Effect of Ni-CNTs/Mesocellular Silica Composite Catalysts on Carbon Dioxide Reforming of Methane. Appl. Catal., A 2014, 475, 16. (31) Bradford, M. C. J.; Vannice, M. A. Catalytic Reforming of Methane with Carbon Dioxide over Nickel Catalysts I. Catalyst Characterization and Activity. Appl. Catal., A 1996, 142, 73.

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Corresponding Author

*E-mail: [email protected]. Tel.: +66 2579 2083. Fax: +66 2561 4621. Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS This work was supported by the Thailand Research Fund and Kasetsart University through the Royal Golden Jubilee Ph.D. Program (Grant No. PHD/0063/2551) and the Kasetsart University Research and Development Institute (KURDI).

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REFERENCES

(1) Wilhite, B. A.; McCready, M. J.; Varma, A. Kinetics of Phenylacetylene Hydrogenation over Pt/γ-Al2O3 Catalyst. Ind. Eng. Chem. Res. 2002, 41, 3345. (2) Dominguez-Dominguez, S.; Berenguer-Murcia, A.; CazorlaAmoros, D.; Linares-Solano, A. Semihydrogenation of Phenylacetylene Catalyzed by Metallic Nanoparticles Containing Noble Metals. J. Catal. 2006, 243, 74. (3) Dominguez-Dominguez, S.; Berenguer-Murcia, A.; Pradhan, B. K.; Linares-Solano, A.; Cazorla-Amoros, D. Semihydrogenation of Phenylacetylene Catalyzed by Palladium Nanoparticles Supported on Carbon Materials. J. Phys. Chem. C 2008, 112, 3827. (4) Weerachawanasak, P.; Praserthdam, P.; Arai, M.; Panpranot, J. A Comparative Study of Strong Metal−Support Interaction and Catalytic Behavior of Pd Catalysts Supported on Micron- and NanoSized TiO2 in Liquid-Phase Selective Hydrogenation of Phenylacetylene. J. Mol. Catal. A: Chem. 2008, 279, 133. (5) Duraczynska, D.; Serwicka, E. M.; Drelinkiewicz, A.; Olejniczak, Z. Ruthenium (II) Phosphine/mesoporous Silica Catalysts: the Impact of Active Phase Loading and Active Site Density on Catalytic Activity in Hydrogenation of Phenylacetylene. Appl. Catal., A 2009, 371, 166. (6) Li, C.; Shao, Z.; Pang, M.; Williams, C. T.; Liang, C. Carbon Nanotubes Supported Pt Catalysts for Phenylacetylene Hydrogenation: Effects of Oxygen Containing Surface Groups on Pt Dispersion and Catalytic Performance. Catal. Today 2012, 186, 69. (7) Navalikhina, M. D.; Kavalerskaya, N. E.; Lokteva, E. S.; Peristyi, A. A.; Golubina, E. V.; Lunin, V. V. Selective Hydrogenation of Phenylacetylene on Ni and Ni−Pd Catalysts Modified with Heteropoly Compounds of the Keggin Type. Russ. J. Phys. Chem. A 2012, 86, 1800. (8) Dominguez-Dominguez, S.; Berenguer-Murcia, A.; LinaresSolano, A.; Cazorla-Amoros, D. Inorganic Materials as Supports for Palladium Nanoparticles: Application in the Semi-hydrogenation of Phenylacetylene. J. Catal. 2008, 257, 87. (9) Tiengchad, N.; Mekasuwandumrong, O.; Na-Chiangmai, C.; Weerachawanasak, P.; Panpranot, J. Geometrical Confinement Effect in the Liquid-Phase Semihydrogenation of Phenylacetylene over Mesostructured Silica Supported Pd Catalysts. Catal. Commun. 2011, 12, 910. (10) Leitmannova, E.; Svoboda, J.; Sedlacek, J.; Vohlidal, J.; Kacer, P.; Cerveny, L. Hydrogenation of Phenylacetylene and 3-Phenylpropyne Using Rh(diene) Complexes under Homogeneous and Heterogeneous Conditions. Appl. Catal., A 2010, 372, 34. (11) Li, C.; Shao, Z.; Pang, M.; Williams, C. T.; Zhang, X.; Liang, C. Carbon Nanotubes Supported Mono- and Bimetallic Pt and Ru Catalysts for Selective Hydrogenation of Phenylacetylene. Ind. Eng. Chem. Res. 2012, 51, 4934. (12) Na-Chiangmai, C.; Tiengchad, N.; Kittisakmontree, P.; Mekasuwandumrong, O.; Powel, J.; Panpranot, J. Characteristics and Catalytic Properties of Mesocellular Foam Silica Supported Pd Nanoparticles in the Liquid-Phase Selective Hydrogenation of Phenylacetylene. Catal. Lett. 2011, 141, 1149. (13) Bautista, F. M.; Campelo, J. M.; Garcia, A.; Luna, D.; Marinas, J. M.; Quiros, R. A.; Romero, A. A. Influence of Surface Support 10110

dx.doi.org/10.1021/ie5014597 | Ind. Eng. Chem. Res. 2014, 53, 10105−10111

Industrial & Engineering Chemistry Research

Article

(32) Richardson, J. T.; Scates, R.; Twigg, M. V. X-ray Diffraction Study of Nickel Oxide Reduction by Hydrogen. Appl. Catal., A 2003, 246, 137. (33) Navarro-Flores, E.; Chong, Z.; Omanovic, S. Characterization of Ni, NiMo, NiW and NiFe Electroactive Coatings as Electrocatalysts for Hydrogen Evolution in an Acidic Medium. J. Mol. Catal. A: Chem. 2005, 226, 179. (34) Chen, R.; Wang, Q.; Du, Y.; Xing, W.; Xu, N. Effect of Initial Solution Apparent pH on Nano-Sized Nickel Catalysts in pNitrophenol Hydrogenation. Chem. Eng. J. 2009, 145, 371. (35) Zeng, C.; Wang, C.; Wang, F.; Zhang, Y.; Zhang, L. A Novel Vapor−Liquid Segmented Flow Based on Solvent Partial Vaporization in Microstructured Reactor for Continuous Synthesis of Nickel Nanoparticles. Chem. Eng. J. 2012, 204−206, 48. (36) Kim, Y. I.; Soundararajan, D.; Park, C. W.; Kim, S. H.; Park, J. H.; Ko, J. M. Electrocatalytic Properties of Carbon Nanofiber Web− Supported Nanocrystalline Pt Catalyst as Applied to Direct Methanol Fuel Cell. Int. J. Electrochem. Sci. 2009, 4, 1548. (37) Romero, A.; Garrido, A.; Nieto-Marquez, A.; Osa, A. R.; de la Lucas, A.; de Valverde, J. L. The Influence of Operating Conditions on the Growth of Carbon Nanofibers on Carbon Nanofiber-Supported Nickel Catalysts. Appl. Catal., A 2007, 319, 246. (38) Zhou, J. H.; Sui, Z. J.; Li, P.; Chen, D.; Dai, Y. C.; Yuan, W. K. Structural Characterization of Carbon Nanofibers Formed From Different Carbon-Containing Gases. Carbon 2006, 44, 3255. (39) Takenaka, S.; Kobayashi, S.; Ogihara, H.; Otsuka, K. Ni/SiO2 Catalyst Effective for Methane Decomposition into Hydrogen and Carbon Nanofiber. J. Catal. 2003, 217, 79. (40) Sano, N.; Yamamoto, S.; Tamon, H. Cr as a Key Factor for Direct Synthesis of Multi-walled Carbon Nanotubes on Industrial Alloys. Chem. Eng. J. 2014, 242, 278. (41) Singh, U. K.; Vannice, M. A. Kinetics of Liquid-Phase Hydrogenation Reactions over Supported Metal Catalysts-A Review. Appl. Catal., A 2001, 213, 1. (42) Tessonnier, J. P.; Pesant, L.; Ehret, G.; Ledoux, M. J.; PhamHuu, C. Pd Nanoparticles Introduced Inside Multi-walled Carbon Nanotubes for Selective Hydrogenation of Cinnamaldehyde into Hydrocinnamaldehyde. Appl. Catal., A 2005, 288, 203.

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