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Chinese Journal of Catalysis
2011, Vol. 32, No. 4
Online: 18 April 2011


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Yu and coworkers, in their article on pages 525–531, reported the preparation of hierarchical flower-like TiO₂ superstructures that were self-assembled from anatase TiO₂ nanosheets with exposed {001} facets by a simple alcohothermal strategy. These TiO₂ superstructures exhibit enhanced photoactivity for the decomposition of acetone in air and methyl orange in aqueous solutions because of the hierarchical porous structure and exposed {001} facets.

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Table of Contents for Vol.32 No. 4 2011, 32 (4):  0-0.  Abstract ( 1253 )   PDF (2928KB) ( 886 )

Research Briefing

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Solid Synthesis of GaxCs2.5-3xH0.5PW12O40 Salts and Their Catalytic Activity in the Isomerization of n-Butane ZHANG Li, YUE Bina, FENG Sujiao, QIAN Linping, HE Heyongb 2011, 32 (4):  521-524.  DOI: 10.1016/S1872-2067(10)60214-8 Abstract ( 3114 )   [Full Text(HTML)] () PDF (462KB) ( 823 )   GaxCs2.5-3xH0.5PW12O40 (x = 0.05, 0.10, and 0.15) salts were prepared using a solid synthesis method and they showed higher catalytic activity than that of Cs2.5H0.5PW12O40 for n-butane isomerization, which possibly comes from their enhanced acid strength as a result of Ga doping.

Research papers

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Photocatalytic Activity of Hierarchical Flower-Like TiO2 Superstructures with Dominant {001} Facets XIANG Quanjun, YU Jiaguo* 2011, 32 (4):  525-531.  DOI: 10.1016/S1872-2067(10)60186-6 Abstract ( 5269 )   [Full Text(HTML)] () PDF (952KB) ( 2252 )   The fabrication of well defined hierarchical structures of anatase TiO2 with a high percentage of reactive facets is of great importance and challenging. Hierarchically flower-like TiO2 superstructures (HFTS) self-assembled from anatase TiO2 nanosheets with exposed {001} facets (up to 87%) were synthesized by a simple alcohothermal strategy in a HF-H2O-C2H5OH mixed solution using titanate nanotubes as precursor. The samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and N2 adsorption-desorption isotherms. The photocatalytic activity was evaluated by the photocatalytic oxidation decomposition of acetone in air and methyl orange in aqueous solution under UV illumination. The photocatalytic activity of HFTS was much higher than that of commercial Degussa P25 and tabular-shaped anatase TiO2 obtained using pure water as the synthesis medium. The enhancement in photocatalytic activity was related to several factors, including the hierarchically porous structure, exposed {001} facets, and increased light harvesting ability. The HFTS was also of interest for use in solar cells, photocatalytic H2 production, optoelectronic devices, sensors, and catalysis.

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Zr-MCM-41 Nanoreactors as Efficient and Reusable Catalysts in the Synthesis of New Aminonitriles by the Strecker Reaction Zohreh DERIKVANDa, Fatemeh DERIKVANDb 2011, 32 (4):  532-535.  DOI: 10.1016/S1872-2067(10)60189-1 Abstract ( 2945 )   [Full Text(HTML)] () PDF (649KB) ( 1307 )   The synthesis and characterization of Zr-MCM-41 nanoreactors and their catalytic activity in the synthesis of new amino nitrile derivatives by the Strecker reaction in high yields and in short reaction times is reported.

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Structure and Photocatalytic Activity of Polythiophene/TiO2 Composite Particles Prepared by Photoinduced Polymerization XU Shoubin, JIANG Long, YANG Haigang, SONG Yuanqing, DAN Yi* 2011, 32 (4):  536-545.  DOI: 10.1016/S1872-2067(10)60207-0 Abstract ( 3947 )   [Full Text(HTML)] () PDF (675KB) ( 2143 )   Polythiophene/titanium dioxide (PTh/TiO2) composite particles were synthesized via the photoinduced polymerization of thiophene in a TiO2-chloroform suspension. The resultant composite particles were characterized by BET analysis, scanning electron microscopy, laser particle size analysis, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS). The XPS spectra indicated that a strong interaction exists between the S sites of the polymer backbone and the TiO2 particles. The UV-Vis DRS spectra showed that the resultant composite particles are responsive to visible light. The photocatalytic activities of the PTh/TiO2 composite particles were examined through the degradation processes of a rhodamine B (RhB) solution under UV irradiation and visible light irradiation. The degradation ratios of the RhB solution were found to be 76% and 98% after UV irradiation (180 min) and visible light irradiation (10 h), respectively. The photocatalysis reactive mechanisms under UV irradiation and visible light irradiation were investigated using disodium ethylenediamine tetraacetate (EDTA-2Na, hole scavenger) and furfuryl alcohol (radical scavenger). The oxidant from the holes and the radicals are competitive. Under UV irradiation, photogenerated holes are the main active species while under visible light irradiation the radicals are the main oxidant for the degradation of RhB.

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In Situ Synthesis of Cu-SAPO-34/Cordierite for the Catalytic Removal of NOx From Diesel Vehicles by C3H8 LIU Zhiqiang, TANG Lei, CHANG Liping, WANG Jiancheng*, BAO Weiren 2011, 32 (4):  546-554.  DOI: 10.1016/S1872-2067(10)60205-7 Abstract ( 3195 )   [Full Text(HTML)] () PDF (662KB) ( 1175 )   A Cu-SAPO-34/cordierite catalyst was prepared by in situ hydrothermal synthesis. The morphology and structure of the Cu-SAPO-34/cordierite samples were characterized by X-ray diffraction, scanning electron microscopy, and physical adsorption-desorption analyzer. The removal of NOx from simulated diesel vehicle exhaust gas was carried out using a fixed-bed reactor. The effects of C3H8, O2 concentrations, and water vapor on the activity of the catalyst were studied. The results indicate that the Cu-SAPO-34 coatings obtained by the in situ synthesis are firm and compact, and the loading amount is found to be more than 20% after one synthesis operation. The surface areas of the Cu-SAPO-34/cordierite catalysts increase greatly compared with that of cordierite. The active Cu component prepared through in situ synthesis can significantly improve the activity of selective catalytic reduction of NOx by C3H8. NOx reduction over the Cu-SAPO-34/cordierite catalyst is more than 60% between 500 and 650 °C. The NOx conversion decreases after the addition of 10% water vapor to the feed gas but the deactivation caused by water vapor is not permanent.

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Preparation of WO3/ZnO Composite Photocatalyst and Its Photocatalytic Performance YU Changlin1,*, YANG Kai1, SHU Qing1, YU Jimmy C2, CAO Fangfang1, LI Xin1 2011, 32 (4):  555-565.  DOI: 10.1016/S1872-2067(10)60212-4 Abstract ( 3826 )   [Full Text(HTML)] () PDF (810KB) ( 2167 )   A series of WO3/ZnO composite photocatalysts with different WO3 concentrations were prepared by a precipitation-grinding method followed by calcination at different temperatures. The prepared samples were characterized by N2 physical adsorption, X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, UV-visible spectroscopy, and photoluminescence spectroscopy. The photocatalytic activity of the samples was evaluated by photocatalytic degradation of acid orange II under UV light (λ = 365 nm) irradiation. The results showed that at the optimal calcination temperature of 600 °C, the WO3/ZnO composite photocatalyst with 2 wt% concentration of WO3 showed about doubled photocatalytic activity compared to pure ZnO. The increase in the photocatalytic activity could be attributed to the coupling of WO3, which suppressed the growth of ZnO particles, increase of the surface area and increased amount of surface OH groups of the sample. The presence of WO3 also restrained the recombination rate of e-/h+ pairs.

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Dicyclopentadiene Hydroformylation in an Aqueous/Organic Two Phase System in the Presence of a Cationic Surfactant PI Xiaodong1, ZHOU Yafen1,2, ZHOU Limei1,2, YUAN Maolin1, LI Ruixiang1, FU Haiyan1,#, CHEN Hua1,* 2011, 32 (4):  566-571.  DOI: 10.1016/S1872-2067(10)60182-9 Abstract ( 3489 )   [Full Text(HTML)] () PDF (427KB) ( 940 )   Dicyclopentadiene (DCPD) hydroformylation catalyzed by the water soluble rhodium complex RhCl(CO)(TPPTS)2 (TPPTS: P(m-C6H4SO3Na)3) was studied in an aqueous/organic two phase system containing a cationic surfactant. The effects of various reaction parameters such as reaction temperature, catalyst concentration, water soluble phosphine TPPTS or TPPDS (C6H5P(m-C6H4SO3Na)2), and surfactant structure were examined. The catalytic activity was better with the ligand TPPTS than with TPPDS. The reaction was accelerated by the addition of the cationic surfactant C16H33N(CH3)2CnH2n+1Br (n = 1, 8, 12, 16) but the accelerating effect was attenuated with an increase of the n value. In the presence of the surfactant, the DCPD conversion increased initially and then decreased as the rhodium concentration increased in the range of 0.05–5.00 mmol/L. The catalyst containing aqueous phase was reused four times without significant decrease in activity and regioselectivity.

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NOx Storage Capacity Enhancement on NiO/Al2O3 Pretreated with a Non-thermal Plasma LI Qiurong1,2,*, WU Jinbao1, HAO Jiming2 2011, 32 (4):  572-581.  DOI: 10.1016/S1872-2067(10)60191-X Abstract ( 3517 )   [Full Text(HTML)] () PDF (538KB) ( 1245 )    In the NOx storage reduction (NSR) technology used to remove NOx from lean burn engines, the NOx storage material is crucial. For NiO/Al2O3 catalysts with different NiO loading prepared by coprecipitation, the maximum storage capacity for NOx occurred at a Ni/Al molar ratio of 0.3 in the catalyst. The intensity of the NiAl2O4 diffraction peak decreased with increased nickel content. When the catalysts were pretreated by a non-thermal plasma (NTP) before calcination at high temperature, the adsorption capacities for NOx increased, with an increase from 345 to 477 μmol/g on the NiO/Al2O3 catalyst with the Ni/Al molar ratio of 0.3. The metal dispersion was increased with the NTP treatment, which resulted in a high surface area. The NOx storage mechanism was discussed on the basis of DRIFTS results, which indicated that NO was first adsorbed on the surface as bridged nitrites, and then the nitrites species was transformed into different kinds of NO3- adsorbed species.

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Tungstophosphoric Acid Supported on Highly Organosoluble Polyamide (PW12/PA): Highly Efficient Catalysts for the Synthesis of Novel 1,3,5-Triaryl-2-pyrazoline Derivatives Razieh FAZAELI1,*, Hamid ALIYAN2, Shadpour MALLAKPOUR3,4, Zahra RAFIEE5, Maryam BORDBAR6 2011, 32 (4):  582-588.  DOI: 10.1016/S1872-2067(10)60203-3 Abstract ( 2779 )   [Full Text(HTML)] () PDF (337KB) ( 1430 )   A novel compound constructed from polyoxometalate (H3PW12O40, PW12) and poly(amidoamine) (PA) was prepared at room temperature in an aqueous solution by an impregnation method. A series of novel 1,3,5-triaryl-2-pyrazoline derivatives was synthesized by the reaction between chalcone and phenylhydrazine in the presence of the title compound, PW12/PA, in high yields. The structures of the compounds obtained were determined by IR and 1H NMR spectra.

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The Effect of La2O3 on Pd Close-Coupled Catalysts YAO Yanling, FANG Ruimei, SHI Zhonghua?, GONG Maochu, CHEN Yaoqiang 2011, 32 (4):  589-594.  DOI: 10.1016/S1872-2067(10)60204-5 Abstract ( 3471 )   [Full Text(HTML)] () PDF (449KB) ( 924 )   Palladium close-coupled catalysts were prepared by impregnation method with different amounts of La2O3 as a promoter. Low temperature N2 adsorption-desorption, X-ray diffraction, H2-temperature programmed reduction (H2-TPR), CO-chemisorption, and X-ray photoelectron spectroscopy (XPS) were used to characterize the effect of La2O3 on the physicochemical properties of the prepared catalysts. Their catalytic activities toward C3H8 conversion were evaluated using a gas mixture that simulates the emissions from a gasoline engine. The results of catalytic activity indicate that the presence of La2O3 significantly improves catalytic performance and enhances the thermal resistance of the catalysts. H2-TPR results suggest that the addition of La2O3 increases the reductive ability of the catalysts and shifts the reduction temperature to a lower value. The XPS and CO-chemisorption results indicate that doping by La2O3 also improves the dispersion of the Pd species and decreases the mean particle size of palladium. The optimal loading amount of La2O3 is 10%.

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Protection of Hydroxyl Groups as a Trimethylsilyl Ether by 1,1,1,3,3,3-Hexamethyldisilazane Promoted by Aspartic Acid as an Efficient Organocatalyst Arash GHORBANI-CHOGHAMARANI*, Masoomeh NOROUZI 2011, 32 (4):  595-598.  DOI: 10.1016/S1872-2067(10)60210-0 Abstract ( 2424 )   [Full Text(HTML)] () PDF (261KB) ( 1412 )   A wide variety of alcohols and phenols were protected as trimethylsilyl ethers using 1,1,1,3,3,3-hexamethyl disilazane catalyzed by aspartic acid as a non-toxic, metal-free, and green organocatalyst at room temperature in acetonitrile under mild and heterogeneous conditions. The procedure is operationally simple and the silylated product was obtained in high yield and purity.

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Effect of Microwave Power and Irradiation Time on the Performance of Pt/C Catalysts Synthesized by Pulse-Microwave Assisted Chemical Reduction WANG Xizhao1,2, ZHENG Junsheng1,2,a, FU Rong1,3, MA Jianxin1,2,b 2011, 32 (4):  599-605.  DOI: 10.1016/S1872-2067(10)60213-6 Abstract ( 3955 )   [Full Text(HTML)] () PDF (1056KB) ( 1185 )   Pt/C catalysts for polymer electrolyte membrane fuel cells were synthesized by pulse-microwave assisted chemical reduction. X-ray diffraction (XRD) and high resolution transmission electron microscope (HRTEM) were used to investigate the microstructure and morphology of the as-prepared catalysts. The electrochemical surface area (ESA) was studied by cyclic voltammetry (CV). Membrane electrode assemblies were fabricated and the as-prepared catalysts were evaluated. The particle size and distribution of Pt nanoparticles on the carbon support greatly depended on the microwave power and irradiation time. XRD and HRTEM showed that the Pt/C catalysts possessed the smallest mean Pt particle size (1.9 nm) and the most uniform distribution among all the synthesized catalysts when the microwave was on for 12 s and off for 180 s, and this was repeated 6 times at a microwave power of 2 kW. A CV revealed that the ESA of the catalyst was 72.3 m2/g and the corresponding maximum power density was 0.572 W/cm2.

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Preparation and Characterization of CO Tolerance Pt-CeO2/C Catalyst for Proton Exchange Membrane Fuel Cells ZHANG Haiyan1,2, LIN Rui1,3,*, CAO Chunhui1,3, MA Jianxin1,2,3,* 2011, 32 (4):  606-611.  DOI: 10.3724/SP.J.1088.2011.01229 Abstract ( 3452 )   [Full Text(HTML)] () PDF (539KB) ( 1605 )   The nano-scale Pt-CeO2/C catalyst was prepared by the co-precipitation method. The results of transmission electron microscopy and X-ray diffraction analysis show that the average size of Pt-CeO2/C noble metal particles (1.5~2.5 nm) is highly dispersed on the carbon supports. Pt-CeO2/C and a commercial Pt/C catalyst from Johnson Matthey Company were investigated by cyclic voltammetry and CO-stripping experiment. The cyclic voltammetry test shows that the Pt-CeO2/C catalyst has similar electrochemical surface area to Pt/C, which indicates that the home-made Pt-CeO2/C catalyst has high electrocatalytic activity for hydrogen oxidation. From the CO-stripping experiment, the Pt-CeO2/C catalyst showed very high CO tolerant activity compared to the Pt/C catalyst. We also fabricated the membrane electrode assembly with Pt-CeO2/C or Pt/C catalyst on the anode (the cathode also used the Pt/C catalyst) and found that Pt-CeO2/C catalyst showed higher performance than Pt/C catalyst. A tentative mechanism was proposed for a possible role of Ce as a co-catalyst in the Pt/C system for CO electrooxidation.

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Structure of Ni/HZSM-5 Catalyst and Its Catalytic Performance for Aqueous Phase Hydrogenation of Sorbitol to Alkanes QIU Ke1,2, ZHANG Qing1, JIANG Ting1,2, MA Longlong1, WANG Tiejun1, ZHANG Xinhua1,2, QIU Minghuang1,2 2011, 32 (4):  612-617.  DOI: 10.3724/SP.J.1088.2011.01016 Abstract ( 3529 )   [Full Text(HTML)] () PDF (589KB) ( 1058 )   A bifunctional Ni/HZSM-5 catalyst was prepared by the conventional impregnation method. The effects of calcination temperature on the structure properties of the catalyst and its catalytic performance for aqueous phase hydrogenation of sorbitol were studied. The results showed that C5~C6 alkanes were effectively obtained by the hydrogenation of the C–O bond in sorbitol and the following isomerization due to the synergism of the metal center and acid support. Moreover, the catalyst calcined at 500 °C exhibited a maximum value of 62.0% for sorbitol conversion and 76.4% of selectivity for pentane and hexane in comparison with other catalyst samples, wherein the isohexane selectivity was about 45.4%. The catalyst samples were characterized by N2 physical adsorption, X-ray diffraction, NH3 temperature-programmed desorption, and H2 temperature-programmed reduction. It was found that the surface area and pore volume of the catalyst calcined at 500 °C were obviously increased. Smaller grains of NiO can be formed from the decomposition of nickel nitrate on the surface of HZSM-5, which can provide with the appropriate amounts of acid and the interaction between the nickel species and acid support for easier hydrogen reduction with the Ni reducibility of 100%. All these factors are closely related to the highest catalytic performance of Ni/HZSM-5 catalyst for aqueous phase hydrogenation of sorbitol.

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Preparation and Photocatalytic Performance of Nano-bismuth Ferrite with Tunable Size XIAN Tao1,2, YANG Hua1,2,*, DAI Jianfeng1,2, WEI Zhiqiang1,2, MA Jinyuan2, FENG Wangjun2 2011, 32 (4):  618-623.  DOI: 10.3724/SP.J.1088.2011.01210 Abstract ( 3424 )   [Full Text(HTML)] () PDF (656KB) ( 2302 )   A modified polyacrylamide gel method was used to fabricate BiFeO3 nanoparticles. Thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy, and X-ray diffraction were used to investigate the thermal decomposition process of xerogel and the formation of BiFeO3 phase. It is demonstrated that high phase purity BiFeO3 nanoparticles can be prepared at a calcination temperature of 600 °C. Bisacrylamide, which acts as a crosslinking agent, plays an important role in tailoring the grain size of the resulting BiFeO3 nanoparticles. With increasing bisacrylamide content, the grain size decreases gradually. As a result, a series of BiFeO3 samples with average grain size of 52–110 nm have been prepared. Scanning electron microscopy reveals that the prepared BiFeO3 nanoparticles are regularly spherical in shape with uniform particle size distribution. The photocatalytic activity of BiFeO3 nanoparticles was investigated by the degradation of methyl orange (MO). The experimental results reveal that they exhibit a pronounced photocatalytic activity for the MO decomposition under ultraviolet and visible-light irradiation. With decrease in particle size, the reactive activity increases. The optimum conditions for the photocatalytic decolorization were determined to be initial MO concentration of ~10 mg/L and catalyst amount of ~2.5 g/L.

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Electrocatalytic Activity of Co3O4/C for Oxygen Reduction and the Reaction Mechanism LI Shang*, ZHU Guangwen, QIU Peng, RONG Gang, PAN Mu 2011, 32 (4):  624-629.  DOI: 10.3724/SP.J.1088.2011.01012 Abstract ( 3430 )   [Full Text(HTML)] () PDF (598KB) ( 3143 )   The Co3O4/C catalyst with nanoparticles was synthesized by a liquid control precipitation method. X-ray diffraction and transmission electron microscopy were used to characterize the structure and morphology of the catalyst. The electrocatalytic activity of the catalyst was investigated by line-scan voltammetry and cyclic voltammetry using rotating disk electrode technique. The results indicated that the Co3O4/C has electrocatalytic activity for the oxygen reduction reaction (ORR). The exchange current density of Co3O4/C catalyst obtained by the Koutecky-Levich theory is 1.1 x10-9 A/cm2. The overall electron transfer number for the ORR was determined to be ~2, suggesting that the ORR catalyzed by Co3O4/C is a 2- electron transfer pathway. The process of oxygen adsorption on the surface of Co3O4/C was simulated through Materials Studio to explore the catalytic mechanism. The state density, electron density, bond length, and adsorption energy of O and Co were calculated. Restricted by the geometric configuration, O2 can only be adsorbed by the Pauling adsorption mode. After adsorption, the O 2p orbit and Co 3d orbit hybridize with each other and form a new chemical bond. The π bond of O2 is mainly weakened by the electron transfer from Co to O. At the same time, the other O atom is activated. H+ can easily bond with the other O and the catalytic reaction occurs through 2- electron transfer pathway.

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The Immobilization of Lipase on Zirconium Nucleotide and Its Catalytic Performance TAO Weihong, YANG Lirong, XU Gang, QIAO Yuanbiao, WU Jianping* 2011, 32 (4):  630-636.  DOI: 10.3724/SP.J.1088.2011.01129 Abstract ( 3008 )   [Full Text(HTML)] () PDF (502KB) ( 898 )   The immobilization of Arthrobacter sp. lipase on zirconium nucleotide nanoparticles was investigated. The effect of immobilization time, pH value, buffer concentration, and lipase amount on the catalytic performance of the immobilized lipase in an organic system was studied. The results showed that the enzyme immobilized on zirconium-uridine monophosphate (30–50 nm) had the best catalytic performance for the resolution of 4-hydroxy-3-methyl-2-(2-propenyl)-2-cyclopenten-1-one. The optimal immobilization conditions were determined to be pH = 8.0, phosphate buffer concentration of 0.03 mol/L with the lipase/support mass ratio of 4 , and immobilization for 6 h. The activity recovery was as high as 6.8 fold of the free lipase and the enantioselectivity (E = 200) was improved (E = 85 for free lipase). Furthermore, the operational stability for the immobilized enzyme was greatly enhanced compared with the free enzyme. The residual activity was kept at 58.7% after 20 batch reactions, while that of the free enzyme was only 4%.

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Simultaneous Removal of Phenol and Cr(VI) by TiO2 Nanotube Array Photoelectrocatalysis WANG Houjin1,2, WU Xiaojing1,2, WANG Yaling1,2, JIAO Zibin1, YAN Shengwei1, HUANG Langhuan1,2,* 2011, 32 (4):  637-642.  DOI: 10.3724/SP.J.1088.2011.01246 Abstract ( 3277 )   [Full Text(HTML)] () PDF (443KB) ( 1190 )   TiO2 nanotube arrays were prepared by electrochemical anodization on pure Ti surfaces. The products were characterized by X-ray diffraction, scanning electron microscopy and electrochemical workstation. The results showed that the prepared sample was anatase with a diameter of about 100 nm and a tube length of about 2 um. The maximum photocurrent could be achieved when the bias potential of 0.5 V was applied on the TiO2 nanotube array electrode. The photoelectrocatalytic properties of the TiO2 nanotube array electrode were evaluated by the simultaneous removal of phenol and Cr(VI). The effects of catalytic processes, pH values, and various initial concentrations of Cr(VI) and phenol on the removal efficiency of phenol and Cr(VI) were investigated. The results indicated that in the photoelectrocatalytic mode, phenol and Cr(VI) removal ratios were 86.7% and 96.9%, respectively, while in the photocatalytic mode they were 48.2% and 65.2%, respectively. The removal efficiency by photoelectrocatalysis was higher than that by photocatalysis. The acidic solutions were favorable for the photoelectrocatalytic simultaneous removal of Cr (VI) and phenol, and the optimum pH was 2. In the phenol-Cr(VI) co-existed system, phenol and Cr(VI) were more efficiently eliminated than in the single phenol or Cr(VI) system. The reduction of Cr(VI) and the oxidation of phenol produced a synergistic effect, which promoted the simultaneous removal of Cr(VI) and phenol.

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Hydrogenation of α-Pinene over Ruthenium Chloride Promoted by Water YANG Xiao1, LIU Shiwei1, XIE Congxia2,*, YU Shitao1, LIU Fusheng1 2011, 32 (4):  643-646.  DOI: 10.3724/SP.J.1088.2011.01225 Abstract ( 3054 )   [Full Text(HTML)] () PDF (360KB) ( 925 )   The water improved hydrogenation of α-pinene was investigated in the presence of ruthenium chloride. The results showed that water significantly promoted the hydrogenation. Compared with the traditional catalysts or RuCl3, the selectivity for product pinane and the molar ratio of cis-/trans-pinane were significantly improved. Under the optimum conditions of 1.8 mg RuCl3·3H2O, 2.5 g α-pinene, m(H2O):m(α-pinene) = 4:1, 5 MPa H2, reaction temperature 160 oC, and reaction time 5 h, the conversion of α-pinene reached 99.7%, the selectivity for cis-pinane was 96.3%, and the molar ratio of cis-/trans-pinane was more than 28. Otherwise, the isolated catalyst phase could be used five times without any treatment, and its catalytic activity was unchanged.

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Synthesis and Characterization of WO3/ZrO2 Solid Acid Catalyst with Hierarchically Porous Structure CHEN Chongcheng1,2, CHEN Hangrong1,a, YU Jianchang2,b, YE Zhengqing1, SHI Jianlin1 2011, 32 (4):  647-651.  DOI: 10.3724/SP.J.1088.2011.01203 Abstract ( 2947 )   [Full Text(HTML)] () PDF (701KB) ( 1332 )   WO3/ZrO2 solid acid catalyst with hierarchically porous structure was prepared by the one-pot hydrothermal method involving templating from a composite surfactant. The catalyst samples were characterized by X-ray diffraction, N2 adsorption-desorption, Raman spectroscopy and NH3 temperature-programmed desorption. The results indicated that WO3 doping significantly increased the BET surface area and provided more surface acid centers. The esterification of acetic acid and butanol showed that the hierarchically porous WO3/ZrO2 solid acid catalyst has excellent catalytic activity and reusability. The 20% WO3/ZrO2 sample calcined at 550 oC for 5 h has the highest catalytic activity.

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Performance of Palygorskite Supported Cu-Mn-Ce Catalyst for Catalytic Oxidation of Toluene SONG Lei, CHEN Tianhu*, LI Yunxia, LIU Haibo, KONG Dejun, CHEN Dong 2011, 32 (4):  652-656.  DOI: 10.3724/SP.J.1088.2011.01218 Abstract ( 2933 )   [Full Text(HTML)] () PDF (802KB) ( 1147 )   A series of Cu-Mn catalyst samples with Ce additive supported on palygorskite (PG) were prepared by the wet impregnation method. The catalyst structure was characterized by X-ray diffraction, transmission electron microscopy (TEM), and temperature-pro- grammed reduction with H2. The state of various active species and their reducibility were investigated and correlated with catalytic performance of the catalyst. The catalyst activity was examined using toluene as a model volatile organic compound. The effect of different active species, the amount of Ce additive, and catalyst calcination temperature on toluene conversion was investigated. The results demonstrated that the active species of the catalyst were loaded on the surface of PG in the form of CuO, Mn2O3, and CeO2, and highly dispersed nanoparticles of the species were observed by TEM. The addition of Ce improved the growth of spinal CuMn2O4 and increased toluene conversion. When molar ratio of Ce/Cu was 0.3, the catalyst showed the highest activity. Toluene conversion reached 99% over the Cu-Mn-Ce/PG catalyst at 288 oC.

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Ethylene-bridged (4-Substituted Indenyl) (Fluorenyl) Zirconium Complexes: Synthesis and Catalytic Behavior for α-Olefins Polymerization HUANG Wenzhong, MA Haiyana, HUANG Jilingb 2011, 32 (4):  657-665.  DOI: 10.3724/SP.J.1088.2011.01239 Abstract ( 2912 )   [Full Text(HTML)] () PDF (633KB) ( 906 )   Three new ethylene-bridged (4-substituted indenyl) (fluorenyl) zirconium complexes (2a–2c) were successfully synthesized. They exhibited high isotactic selectivity, which increased with the decrease of polymerization temperature for the polymerization of propylene upon the activation of MAO (methylaluminoxane). Complex 2a with 2-methyl group on indenyl displayed the highest isotactic selectivity of 93.6% at 0 oC. At 60 oC, complexes 2a–2c reached their optimum catalytic activity, and complex 2a displayed the highest activity of 7.80x106 g PP/(mol-Zr.h). Meanwhile, complexes 2a–2c were also studied for ethylene homopolymerization and linear polyethylenes with broad molecular weight distributions were obtained. Complex 2c with 4-isopropyl substituent on indenyl showed high activity of 3.45x106 g PE/(mol-Zr.h) even at a low Al/Zr molar ratio of 500.

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Catalytic Reduction of NOx over MnOx Coated TiO2 Nanotube Arrays ZHAO Chongbin, YANG Hangsheng*, ZHOU Huan, QIU Famin, ZHANG Xiaobin 2011, 32 (4):  666-671.  DOI: 10.3724/SP.J.1088.2011.01127 Abstract ( 3168 )   [Full Text(HTML)] () PDF (821KB) ( 1081 )   Catalytic reduction of NOx with NH3 was studied over MnOx coated TiO2 nanotube arrays prepared by anodic oxidation. When the MnOx was deposited inside the TiO2 nanotubes, the good NOx removal efficiency was achieved under relatively low reaction temperature, such that NOx removal efficiency of over 90% was always obtained at 150–250 °C, particularly at 200 °C, it reached 99.9%. However, when the reaction temperature was higher than 250 °C, a suppression of NOx removal was observed. This is probably because that the diffusion of NO molecules into TiO2 nanotubes was controlled by Knudson diffusion.

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Infrared Spectroscopy Study of CO Adsorption on Rh-Mn/SiO2 Catalyst for C2-Oxygenates Synthesis from Syngas CHEN Mingying1, WENG Weizheng1,a, HUA Weiqi2, YI Xiaodong1, WAN Huilin1,b 2011, 32 (4):  672-681.  DOI: 10.3724/SP.J.1088.2011.01132 Abstract ( 3214 )   [Full Text(HTML)] () PDF (921KB) ( 1154 )   The Rh-xMn/SiO2 (x is Mn/Rh atomic ratio = 0~3) catalyst samples were prepared by conventional co-impregnation. The samples were characterized by transmission electron microscopy, X-ray diffraction and catalytic performance evaluation using CO hydrogenation to C2-oxygenates. CO adsorption behavior over Rh-xMn/SiO2 catalyst under CO and syngas atmosphere at 50 and 280 °C, temperature-programmed reaction of CO with H2 on the Rh/SiO2 and Rh-0.5Mn/SiO2 catalyst samples between 50 and 280 °C, and the change of the gem-dicarbonyl species with increasing temperature under CO atmosphere and vacuum were also studied by infrared spectroscopy. The results showed that, when the temperature was higher than 200 °C, the gem-dicarbonyl species was undetectable on the catalyst in the presence of CO, implying that Rh+ site is unlikely the active site for CO insertion. The addition of Mn promoter resulted in the formation of tilted CO. The addition of Mn could be also in favor of weakening the Rh-C bond in the linear CO adspecies, which facilitated the linear CO migration on the catalyst surface and enhanced the rate of CO insertion into CHx. This is consistent with the results from the experiment to improve C2-oxygenates selectivity with addition of Mn into Rh/SiO2 catalyst. The formyl adspecies was detected by infrared spectroscopy in the experiment of temperature-programmed reaction of syngas over Rh-0.5Mn/SiO2 catalyst. This result suggests that addition of Mn to Rh/SiO2 is helpful to stabilize formyl species and this will be favorable to enhance the rate of hydrogen-assisted CO dissociation during the hydrogenation of CO to C2-oxygenates.

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Epoxidation of Styrene with Hydrogen Peroxide over MgO Catalyst BIAN Xiaolian, GU Qingming, SHI Lei, SUN Qi* 2011, 32 (4):  682-687.  DOI: 10.3724/SP.J.1088.2011.01161 Abstract ( 3097 )   [Full Text(HTML)] () PDF (513KB) ( 1187 )   A solid MgO catalyst was prepared by direct thermal decomposition of the Mg(NO3)2·6H2O precursor. The epoxidation of styrene was studied over the MgO using H2O2 as an oxidant in the presence of acetonitrile as solvent. The catalyst samples were characterized by X-ray diffraction, N2 adsorption-desorption, thermogravimetry, and CO2 temperature-programmed desorption. The results indicated that the strength of basic sites on the MgO catalyst is the key factor for the excellent performance of the catalyst. Enhancement of the strength of basic sites can increase the styrene conversion. In contrast, the number of basic sites, surface area, and pore volume of MgO have a relatively minor effect on catalytic activity. The MgO sample prepared by calcining Mg(NO3)2·6H2O at 750 oC showed the most strength of basic sites and the highest catalytic activity among the MgO samples calcined at 450–850 oC. Under the optimized reaction conditions, H2O2/styrene molar ratio = 6, acetonitrile as solvent, 60 oC, and 10 h, the conversion of styrene and the selectivity to epoxyethylbenzene were 97.0% and 88.4%, respectively.

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Preparation of Acidic Resin-Carbon Composite Material through the Sulfonation and Carbonization of Polyphenyl ZHAO Yu, FENG Hongshu, XIE Jianxin, SHEN Jianyi* 2011, 32 (4):  688-692.  DOI: 10.3724/SP.J.1088.2011.01204 Abstract ( 2314 )   [Full Text(HTML)] () PDF (503KB) ( 905 )   Treatment of polyphenyl in concentrated H2SO4 at 170 oC resulted in its sulfonation and carbonization, leading to the formation of acidic resin-carbon composite material with the surface area of about 14 m2/g and strong acid sites of about 1.2 mmol/g related to –SO3H groups. The microcalorimetric adsorption of ammonia showed the high initial adsorption heat, indicating that the formation of pyrosulfuric groups from the sulfonic groups on the surface was unlikely. In addition, it was found that some of the sulfonic groups on such composite material were highly stable since they began to decompose only at a temperature higher than 400 oC. Such acidic composite material was also found to be highly active for the etherification of isopentene with methanol to produce tert-amyl methyl ether. In fact, it was more active for the etherification than the acidic carbon prepared from the sulfonation and carbonization of glucose.

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Catalytic Performance of Imidazolide Basic Ionic Liquid in Knoevenagel Reactions in Aqueous Media CHEN Xuewei, SONG Hongbing, LI Xuehui*, WANG Furong, QIAN Yu 2011, 32 (4):  693-698.  DOI: 10.3724/SP.J.1088.2011.01238 Abstract ( 3125 )   [Full Text(HTML)] () PDF (481KB) ( 1011 )   The synthesis and characterization of the basic ionic liquid, 1-butyl-3-methylimidazolium imidazolide ([Bmim]Im), were reported intensively. [Bmim]Im has strong basicity and relatively good thermal stability, and it was used as a novel catalyst for the Knoevenagel reactions in aqueous media. [Bmim]Im acted as both a base catalyst and a phase transfer catalyst in the Knoevenagel reaction. In addition, [Bmim]Im together with aqueous media had good recycle ability. Aqueous media, low catalyst concentration, simple separation workup, ambient temperature, and high yield are the characteristic features of the present catalytic protocol.

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Carbon-Modified TiO2 Visible Light Photocatalyst Prepared Using Phenolic Resin as Carbon Source CHEN Lijing, WANG Ting, CHEN Feng*, ZHANG Jinlong 2011, 32 (4):  699-703.  DOI: 10.3724/SP.J.1088.2011.01216 Abstract ( 3407 )   [Full Text(HTML)] () PDF (605KB) ( 1228 )   A carbon-modified titanium dioxide photocatalyst, PF/TiO2, was prepared by calcining self-prepared phenolic resin (PF) and TiO2 in N2 atmosphere. The as-prepared PF/TiO2 samples were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy (XPS), and UV-Vis diffuse reflectance spectroscopy. PF/TiO2 has similar crystal phase and morphology to raw TiO2 and has significant absorption in the visible region. The XPS observed the presence of Cn, C–OH(C–O–C), and C=O(COO) species, which confirms that there is graphite carbonaceous matter on the surface of PF/TiO2. During the calcination, the phenolic resin on the surface of PF/TiO2 has been carbonized. The photocatalytic performance of PF/TiO2 under visible light was evaluated by the degradation of methyl orange. The photocatalytic activity of PF/TiO2 is greatly higher than that of bare TiO2. The PF dosage for preparing PF/TiO2 with the highest visible light photocatalytic activity is 2%, corresponding to a carbonaceous matter content of 1.33% in PF/TiO2.