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Chinese Journal of Catalysis
2011, Vol. 32, No. 7
Online: 18 July 2011


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Dr. Zhu et al. in their article on pages 1149–1155 reported the use of two types of 25-atom gold nanoclusters (sphere vs. rod) as catalysts for the selective oxidation of styrene and chemoselective hydrogenation of benzalacetone and showed that different arrangements of the gold atoms give different catalytic properties. Spherical Au₂₅ is significantly more ac-tive than rod-shaped Au₂₅. They proposed that volcano-like atomic sites on the surface of the Au₂₅ sphere and the nature of its core-shell electronic structure are responsible for the higher activity of the Au₂₅ sphere. This work demonstrated the importance of the geometric structure of a catalyst.

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Table of Contents for Vol.32 No. 7 2011, 32 (7):  0-0.  Abstract ( 1190 )   PDF (1837KB) ( 1140 )

Summary

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Role of Chemical Kinetics in the Heterogeneous Catalysis Studies L. A. PETROV, Y. ALHAMED, A. AL-ZAHRANI, M. DAOUS 2011, 32 (7):  1085-1112.  DOI: 10.1016/S1872-2067(10)60225-2 Abstract ( 3556 )   [Full Text(HTML)] () PDF (510KB) ( 3770 )   The paper presents shortly some of the important elements of the theory and of the practical applications of the kinetics of heterogeneous catalytic reactions. Discussed are some of the most important concepts of the kinetics of complex heterogeneous catalytic reactions, methodology of building kinetic models and mathematical treatment of experimental data, influence of heat and mass transfer, types of laboratory reactors, kinetics and nanosized catalysts and others. Examples for use of the kinetic studies for the development and application of industrial catalysts and modeling of industrial reactors are presented.

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Research Progress in Vanadium-Free Catalysts for the Selective Catalytic Reduction of NO with NH3 LIU Fu-Dong, DAN Wen-Po, SHI Xiao-Yan, ZHANG Chang-Bin, HE Hong 2011, 32 (7):  1113-1128.  DOI: 10.3724/SP.J.1088.2011.10315 Abstract ( 4460 )   [Full Text(HTML)] () PDF (690KB) ( 3922 )   Selective catalytic reduction of NO with NH3 (NH3-SCR) is a well-proven technique for the removal of NOx from stationary sources such as coal-fired power plants, and is also one of the most promising techniques for the NOx elimination from diesel exhaust under oxygen-rich conditions. Due to some inevitable disadvantages of the present V2O5-WO3 (MoO3)/TiO2 catalyst for industrial use, many researchers focus on the development of novel, highly efficient, stable, environmental-friendly and vanadium-free NH3-SCR catalysts. The research progress in the field of vanadium-free NH3-SCR catalysts is reviewed, including zeolite catalysts (such as Fe-zeolite catalysts and Cu-zeolite catalysts) and oxide catalysts (such as Fe-based oxide catalysts, Mn-based oxide catalysts, and other vanadium-free oxide catalysts). Several aspects in this field, including the evaluation of catalytic performance, the structure analysis of active sites, the improvement of low temperature activity, the study of NH3-SCR reaction mechanism, the enhancement of H2O/SO2 durability, and the feasibility analysis for industrial use, have been discussed in detail. The possible developing orientation and research interests in the field of vanadium-free NH3-SCR catalysts are previewed.

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Cu-Catalyzed Coupling of Aryl Iodides with Thiols Using Carbonyl-Phosphine Oxide Ligands WANG Hao-Long, WAN Bo-Shun 2011, 32 (7):  1129-1132.  DOI: 10.1016/S1872-2067(10)60243-4 Abstract ( 3806 )   [Full Text(HTML)] () PDF (384KB) ( 937 )   A series of carbonyl-phosphine oxide ligands were synthesized from 2-bromophenylaldehyde and used in Cu-catalyzed C–S coupling reactions. Aryl iodide and aryl bromide reacted with thiols efficiently upon catalysis under mild reaction conditions and a yield of up to 99% was obtained.

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Novel Aqueous/Organic Biphasic System for Thermoregulated Phase-Transfer Catalysis with Rhodium Nanoparticles CHEN Zhi-Jun, WANG Yan-Hua, JIANG Jing-Yang, JIN Zi-Lin 2011, 32 (7):  1133-1137.  DOI: 10.1016/S1872-2067(10)60245-8 Abstract ( 3202 )   [Full Text(HTML)] () PDF (287KB) ( 819 )   An aqueous/1-pentanol biphasic system was developed for thermoregulated phase-transfer catalysis with rhodium nanoparticles in which thermoregulated ligand Ph2P(CH2CH2O)22CH3-stabilized Rh nanoparticles were used as catalysts for the hydrogenation of olefins. Under the optimized reaction conditions, the conversion of cyclohexene and the yield of cyclohexane were 99%. The catalyst can be easily separated from the product by phase separation and it can be recycled eight times without a loss of activity.

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Isomerization of α-Pinene over Immobilized AlCl3 Catalysts WU Yi-Hui, TIAN Fu-Ping, HE Min, CAI Tian-Xi 2011, 32 (7):  1138-1142.  DOI: 10.1016/S1872-2067(10)60244-6 Abstract ( 2748 )   [Full Text(HTML)] () PDF (457KB) ( 1022 )   Immobilized AlCl3 catalysts supported on γ-Al2O3 and SiO2 were prepared by a two-step vapor method and their catalytic activities were evaluated by the liquid phase isomerization of α-pinene for the first time. The results showed that the immobilized AlCl3 catalyst gave excellent catalytic performance for the isomerization of α-pinene. The AlCl3/SiO2 catalyst gave 98.4% conversion of α-pinene and 93.7% selectivity for the main products such as camphene, limonene, and terpinolene at a reaction temperature of 40 °C. The AlCl3/γ-Al2O3 catalyst gave much higher activity, 95.5% conversion of α-pinene and 94.4% selectivity for the main products even at temperatures as low as 30 °C. The excellent catalytic performance of the immobilized AlCl3 catalysts is due to their strong acidity.

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One-Step Synthesis of Chiral Dimethyl 2-Oxo-3-phenyl-glutarate in the Asymmetric Triple-carbonylation of Styrene WANG Lai-Lai, ZHANG Qin-Sheng, CUI Yu-Ming 2011, 32 (7):  1143-1148.  DOI: 10.1016/S1872-2067(10)60253-7 Abstract ( 3367 )   [Full Text(HTML)] () PDF (499KB) ( 834 )   The in-situ preparation of the novel chiral catalyst precursor, which are composed of (S)-2,2',6,6'-tetramethoxy- 4,4'-bis(diphenylphosphine)-3,3'-bipyridine ((S)-P-PHOS) and palladium 2,4-pentanedionate, have been described. These complexes were found to be effective in the asymmetric triple-carbonylation of styrene, reaching up to [α]D20 = +27o (c, 0.28, CH2Cl2) for dimethyl 2-oxo-3-phenyl-glutarate using benzoquinone as oxidant, p-toluenesulfonic acid as co-catalyst, and methanol as solvent.

Research papers

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Comparison of the Catalytic Properties of 25-Atom Gold Nanospheres and Nanorods Yan ZHU, Huifeng QIAN, Anindita DAS, Rongchao JIN 2011, 32 (7):  1149-1155.  DOI: 10.1016/S1872-2067(10)60238-0 Abstract ( 2825 )   [Full Text(HTML)] () PDF (282KB) ( 1076 )   The catalytic properties of two nanocluster catalysts with atomically precisely known structures, icosahedral two-shelled Au25(SC2H4Ph)18 nanospheres and biicosahedral Au25(PPh3)10(SC2H4Ph)5Cl2 nanorods, were compared. Their catalytic performance in the two reactions of the selective oxidation of styrene and chemoselective hydrogenation of α,β-unsaturated benzalacetone was investigated. The catalytic activities of icosahedral Au25(SC2H4Ph)18 nanospheres were superior to those of the bi-icosahedral Au25(PPh3)10(SC2H4Ph)5Cl2 nanorods for both reactions. The better catalytic performance of the Au25(SC2H4Ph)18 nanospheres can be attributed to their unique core-shell (Au13/Au12) geometric structure that has an open exterior atomic shell and to their electronic structure with an electron-rich Au13 core and an electron-deficient Au12 shell.

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Influence of Ultrasound Impregnation on the Performance of Co/Zr/SiO2 Catalyst during Fischer-Tropsch Synthesis ZHOU Xiao-Feng, CHEN Qing-Ling, TAO Yue-Wu, WENG Hui-Xin 2011, 32 (7):  1156-1165.  DOI: 10.1016/S1872-2067(10)60234-3 Abstract ( 3546 )   [Full Text(HTML)] () PDF (790KB) ( 1236 )   A Co/Zr/SiO2 catalyst for Fischer-Tropsch synthesis was prepared under an ultrasound environment. The influence of different ultrasonic powers on catalyst performance was studied. The catalysts were characterized by N2 physisorption, X-ray diffraction, H2 temperature-programmed desorption, H2 temperature-programmed reduction, and transmission electron microscopy. The results show that ultrasound assisted in increasing the BET surface area of the catalysts and the even the dispersion of small cobalt crystallites on the support. When higher power ultrasound was used these characteristics of the catalyst changed remarkably. The pH of the Co(NO3)2 aqueous solution decreased with an increase in high power ultrasound treatment time, which led to a weak interaction between the smaller cobalt particles and the silica support. In addition, less cobalt silicate was formed on the catalyst. Under the same reaction conditions, the catalyst activity and stability were superior to that of the other catalysts because of higher dispersion and reduction. For example, the initial conversion of CO was 95.5% at 493 K, 2 MPa, H2/CO = 2.0, and GHSV = 1000 h-1, and it was 90.9% after 48 h.

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A Novel Magnetically Recyclable Catalyst: Molybdenum Oxide Supported on Hydroxyapatite-encapsulated γ-Fe2O3 for Olefin Epoxidation YUAN Cheng-Yuan, ZHANG Yan, CHEN Jing 2011, 32 (7):  1166-1172.  DOI: 10.1016/S1872-2067(10)60226-4 Abstract ( 2699 )   [Full Text(HTML)] () PDF (630KB) ( 1131 )   Hydroxyapatite-encapsulated magnetic γ-Fe2O3 (HAP-γ-Fe2O3) was synthesized and used as catalyst support. Molybdenum oxide nanoparticles were supported on HAP-γ-Fe2O3 by incipient wetness impregnation (MoOx/HAP-γ-Fe2O3). High-resolution transmission electron microscopy characterization demonstrated the formation of γ-Fe2O3 nanocrystallites with a mean diameter of 1–3 nm within the HAP matrix. The molybdenum oxide dispersed on the surface of HAP-γ-Fe2O3 showed good catalytic activities for the epoxidation of various olefins with tert-butyl hydroperoxide as oxidant. The magnetism of MoOx/HAP-γ-Fe2O3 provided a convenient route for the separation of the catalyst from the reaction mixture by a magnet. The catalyst was recycled at least five times without appreciable loss of catalytic activity.

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Phosphorous-Modified TiO2 with Excellent Thermal Stability and Its Application to the Degradation of Pollutants in Water JIN Chen, QIU Shun-Chen, ZHU Yue-Xiang, XIE You-Chang 2011, 32 (7):  1173-1179.  DOI: 10.1016/S1872-2067(10)60229-X Abstract ( 3093 )   [Full Text(HTML)] () PDF (515KB) ( 752 )   The phosphorous-modified TiO2 (P-TiO2) was synthesized by a hydrothermal method. The as-prepared P-TiO2 was evaluated for the degradation of methylene blue, the dechlorination of 4-chlorophenol, and the inactivation of Escherichia coli. In all these experiments, P-TiO2 shows superior activity compared with pure TiO2 and even better activity than the commercially available P25 in most cases. By carrying out methylene blue degradation in the presence of different scavengers, •OH radicals were found to be the dominant reactive oxidizing species. The excellent performance of P-TiO2 was correlated with its pronounced ability to generate •OH radicals under illumination. We also found that P-TiO2 is extraordinarily stable against annealing. Its transformation from anatase to rutile does not occur until calcination as high as 950 ºC. This phase transformation is retarded since the phosphate species on the surface of the particles acts as a barrier to grain boundary nucleation. This peculiar feature of P-TiO2 gives it reliable performance during water decontamination even after calcination at 900 ºC since it retains a 100% anatase phase at this stage.

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Silica Sulfuric Acid: An Efficient Heterogeneous Catalyst for the One-Pot Synthesis of 1,4-Dihydropyridines under Mild and Solvent-Free Conditions Bandita DATTA, M. Afzal PASHA 2011, 32 (7):  1180-1184.  DOI: 10.1016/S1872-2067(10)60252-5 Abstract ( 3450 )   [Full Text(HTML)] () PDF (295KB) ( 2366 )   A series of 1,4-dihydropyridines have been prepared by a one-pot condensation of aldehydes, ethyl acetoacetate, and ammonium acetate in the presence of a heterogeneous catalyst silica sulfuric acid at room temperature under solvent-free condition. This new protocol has the advantage of short reaction time and excellent yields, and is an environmentally benign route to the synthesis of 1,4-dihydropyridines.

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Rh/ZnO-Al2O3 Catalysts for Selective Hydrogenation of Crotonaldehyde Mouna AOUN, Aicha BENAMAR, Mohamed CHATER 2011, 32 (7):  1185-1190.  DOI: 10.1016/S1872-2067(10)60240-9 Abstract ( 3038 )   [Full Text(HTML)] () PDF (177KB) ( 1208 )   Gas phase hydrogenation of crotonaldehyde was performed over 1 wt% Rh/ZnO-Al2O3 catalysts with various Zn/Rh atomic ratios. Monometallic Rh/Al2O3 was also prepared for comparison. The samples were prepared by the successive impregnation of Al2O3 with chloride precursors of zinc and rhodium. The solids have been characterized by H2 chemisorption, temperature-programmed reduction, scanning electron microscopy, and cyclohexane dehydrogenation. Their catalytic behaviour in the gas phase crotonaldehyde hydrogenation reaction after reduction treatment in flowing hydrogen at 723 K was investigated. The relationship between catalytic activity, selectivity for crotyl alcohol, and physicochemical properties of the catalysts was examined. Results obtained showed that the presence of Zn clearly promotes the hydrogenation of the carbonyl bond. The catalyst with Zn/Rh atomic ratio of 5 displayed good catalytic stability and the highest selectivity for crotyl alcohol (70%) along with alloy formation.

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Preparation of Heterogeneous Mesoporous Silica-Supported 12-Tungstophosphoric Acid Catalyst and Its Catalytic Performance for Cyclopentene Oxidation YUAN Cheng-Yuan, CHEN Jing 2011, 32 (7):  1191-1198.  DOI: 10.1016/S1872-2067(10)60236-7 Abstract ( 3294 )   [Full Text(HTML)] () PDF (496KB) ( 838 )   Keggin-structured 12-tungstophosphoric acids were immobilized onto the surface of amine-modified mesoporous sieve SBA-15 as onium salts. All the catalyst materials were characterized by X-ray diffraction, N2 physisorption, Fourier transform infrared spectroscopy, thermal gravimetric analysis, and X-ray photoelectron spectroscopy for their structural integrity and physicochemical properties. Characterization of the catalysts confirmed an ordered hexagonal mesostructure for SBA-15 and that the Keggin structure of the heteropolyanions on the amine-modified SBA-15 was preserved. The catalytic activities of the catalysts were evaluated for the liquid-phase oxidation of cyclopentene with 50% hydrogen peroxide as the oxidant in tert-butanol. A 100% conversion of cyclopentene and an 81% selectivity for glutaraldehyde were obtained and these were higher than that for the catalysts prepared by direct impregnation. The stability and reusability of the catalysts were studied and the catalysts could be reused at least five times, which indicates their excellent reusability. The influence of reaction temperature and reaction time was also investigated. In addition, a reaction mechanism was proposed.

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A Novel Visible-Light-Driven Semiconductor Photocatalyst: Nano-Yttrium Manganite WANG Shi-Fa, YANG Hua, XIAN Tao 2011, 32 (7):  1199-1203.  DOI: 10.3724/SP.J.1088.2011.10151 Abstract ( 3130 )   [Full Text(HTML)] () PDF (423KB) ( 1150 )   Yttrium manganite (YMnO3) nanoparticles were prepared by a polyacrylamide gel technique. X-ray diffraction analysis indicates that the as-synthesized YMnO3 nanocrystallites crystallize majorly into a hexagonal perovskite structure and minorly into an orthorhombic perovskite structure without the presence of any other impurities. Scanning electron microscope observation shows that the prepared YMnO3 nanoparticles are regularly spherical in shape and highly uniform in size with an average diameter of about 45 nm. Ultraviolet-visible diffuse reflectance spectroscopy was used to investigate the light-absorbing properties of YMnO3 nanoparticles, and the value of the optical bandgap energy is obtained to be 1.31 eV. The photocatalytic activity of YMnO3 nanoparticles was investigated by the degradation of methyl red. The experimental results reveal that the nano-YMnO3 exhibits a pronounced photocatalytic activity for methyl red decomposition under ultraviolet and visible light irradiation.

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Pd(OAc)2-Catalyzed Ligand-Free Suzuki Reaction in Ethylene Glycol at Room Temperature LIU Chun, HAN Na, YUAN Hao, HE Xiao-Yu, JIN Zi-Lin 2011, 32 (7):  1204-1207.  DOI: 10.3724/SP.J.1088.2011.10225 Abstract ( 2925 )   [Full Text(HTML)] () PDF (268KB) ( 1148 )   An aerobic and efficient protocol has been developed for the Pd(OAc)2-catalyzed ligand-free Suzuki reaction of aryl bromides with aryl boronic acids in ethylene glycol at room temperature, affording cross-coupling products in good to excellent yields. Under the optimized reaction conditions (i.e., 0.5 mmol ArBr, 0.75 mmol ArB(OH)2, 0.5 mol% Pd(OAc)2, 1.0 mmol K3PO4·7H2O, and 2 ml ethylene glycol), the Suzuki reaction between 4-bromoanisole and phenylboronic acid provided a 95% isolated yield in 20 min.

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Theoretical Study of Cα–H Hydroxylation of 4-Chloro-N-Cyclopropyl-N-Isopropylaniline Catalyzed by Cytochrome P450 LI Dong-Mei, LIU Jian-Yong 2011, 32 (7):  1208-1213.  DOI: 10.3724/SP.J.1088.2011.10303 Abstract ( 2967 )   [Full Text(HTML)] () PDF (507KB) ( 906 )   The reaction mechanism of Cα–H hydroxylation of 4-chloro-N-cyclopropyl-N-isopropylaniline catalyzed by cytochrome P450 was investigated using the density functional theory. The Becke’s three-parameter hybrid exchange functional and the Lee-Yang-Parr correlation functional (B3LYP) were used in the structure optimization and single-point energy calculations. There are two Cα–H hydroxylation reaction pathways for 4-chloro-N-cyclopropyl-N-isopropylaniline catalyzed by P450. One is Cα–H hydroxylation at the cyclopropyl group, and the other is Cα–H hydroxylation at the isopropyl group. Our calculations demonstrate that the Cα–H activation at both the cyclopropyl group and the isopropyl group is a hydrogen atom transfer process, and the reaction is concerted. Since the Cα–H activation energy on the high-spin quartet state is much higher than that on the low-spin (LS) doublet state, the Cα–H hydroxylation proceeds in a spin-selective manner, mostly on the LS state. Comparison of the energy barriers for the two reaction pathways predicts a preponderance of Cα–H hydroxylation at the cyclopropyl group over that on the isopropyl group by roughly a ratio of 1.8:1, which means that the N-decyclopropylation branch is 64% and the N-deisopropylation branch is 36% during the dealkylation of 4-chloro-N-cyclopropyl-N-isopropylaniline. This is in agreement with former experimental results.

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Preparation of Al2O3-MgO Acid/Base Bifunctional Material with High Specific Surface Area Using Degreasing Cotton as Exotemplate 蓝Dong-Xue , LIN Dan, ZHAO Hui-Min, MA Li, CHUN Yuan 2011, 32 (7):  1214-1219.  DOI: 10.3724/SP.J.1088.2011.10237 Abstract ( 2830 )   [Full Text(HTML)] () PDF (748KB) ( 1089 )   A series of Al2O3-MgO mixed oxide samples were prepared via an exotemplating pathway using degreasing cotton as template and magnesium acetate and aluminum nitrate as MgO and Al2O3 precursors, respectively. The resulting solid acid/base bifunctional material samples were characterized by X-ray diffraction, scanning electron microscopy, and nitrogen adsorption. It was found that these as-prepared Al2O3-MgO material samples replicated the biomorph of cotton fibre and represented high specific surface area (206 m2/g). Amorphous structure was formed at lower Mg content, and the nanocrystals of MgO appeared when the molar ratio of Mg/Al increased to 1. In the methylation of cyclopentadiene, the biomorphic solid acid/base bifunctional material exhibited the catalytic performance much better than the catalyst prepared without using cotton template, and the best result was achieved with a Mg/Al ratio of 20.

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Preparation and Characterization of Au/CuxMnyOz Catalyst and Its Catalytic Performance for CO Removal SHE Yu-Sheng, SUN Wei-Hua, ZHAN Ying-Ying, LIN Xing-Yi, ZHENG Qi 2011, 32 (7):  1220-1226.  DOI: 10.3724/SP.J.1088.2011.10228 Abstract ( 3133 )   [Full Text(HTML)] () PDF (1627KB) ( 1026 )   This paper presented the study on the catalytic performance of a deposition-precipitation prepared Au catalyst supported on copper-manganese complex oxide, which was synthesized via a sol-gel method. This Au/CuxMnyOz catalyst with a low Au content exhibited high activity for both preferential CO oxidation and water-gas shift reaction. The structure-activity relationship was investigated by N2 physisorption, X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, H2 temperature-programmed reduction, and X-ray fluorescence characterization. The results revealed that the CuxMnyOz samples exist mainly in the form of nonstoichiometric spinel Cu1.5Mn1.5O4 phase, which favors the CO conversion in both CO removal reactions. Most Au species dispersed onto the surface of Cu-Mn complex oxide in the metallic state of Au0. The relatively strong interaction between Au and support enhanced the reducibility of Au/CuxMnyOz catalyst, which is also responsible for the excellent performance of the as-prepared catalyst.

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Selective Catalytic Reduction of NO with NH3 on Modified ZrO2-MnO2 Monolithic Catalysts QIU Chun-Tian, LIN Tao, ZHANG Qiu-Lin, XU Hai-Di, CHEN Yao-Qiang, GONG Mao-Chu 2011, 32 (7):  1227-1233.  DOI: 10.3724/SP.J.1088.2011.10245 Abstract ( 3213 )   [Full Text(HTML)] () PDF (626KB) ( 2331 )   A ZrO2-MnO2 catalyst was prepared by the co-precipitation method, and modified with CeO2, MoO3, and WO3 by impregnation. The catalytic activity of the monolithic catalysts for selective catalytic reduction of NOx with NH3 (NH3-SCR) was studied. All the catalysts were characterized by low temperature nitrogen adsorption-desorption, X-ray diffraction, X-ray photoelectron spectroscopy, and NH3/NO-temperature-programmed desorption. The results show that the phase of the catalysts is Mn0.2Zr0.8O1.8 solid solution, and CeO2 and WO3 are well dispersed in catalysts. When adding MoO3 or WO3 into the catalyst, some medium-strength acid sites and the strongly adsorbed NO species that are beneficial to the elevated temperature catalytic activity increase. Mn and Ce exist as Mn4+ and Ce4+. The low temperature SCR activity is improved by the modification with CeO2, but the temperature window of the reaction is relatively narrow. When MoO3 or WO3 is introduced into CeO2/ZrO2-MnO2, the catalyst exhibits better catalytic performance and wider temperature window. The light-off temperature of WO3/CeO2/ZrO2-MnO2 is 176 oC, and the NOx conversion is over 90% in the temperature range of 240–424 oC, and it has good low-temperature activity and wide temperature window.

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Microwave Irradiation Synthesis of SAPO-31 Molecular Sieve and Its Characterization and Catalytic Performance YANG Jie, WU Wei, ZHOU Ya-Jing, WU Guang, ZHAO Ai-Juan, JI He-Jia-Ning- O V, TUO Ke-Ta-Lie-Fu- A V, YI Qie-Fu-Si-Ji- G V 2011, 32 (7):  1234-1241.  DOI: 10.3724/SP.J.1088.2011.10138 Abstract ( 2965 )   [Full Text(HTML)] () PDF (838KB) ( 1041 )   AlPO4-31 molecular sieve was synthesized by microwave irradiation using aluminum isopropoxide, orthophosphoric acid, and di-n-butylamine as sources of aluminum, phosphorus, and template, respectively. The crystallization conditions of AlPO4-31 were optimized. SAPO-31 molecular sieve samples with different silicon contents were synthesized at the optimal conditions. The structure and acidity of the samples were characterized by X-ray diffraction, N2 physical adsorption, scanning electron microscopy, 29Si MAS NMR, NH3 temperature-programmed desorption, FT-IR of adsorbed pyridine. The catalytic performance of Pd/SAPO-31 bifunctional catalyst for hydroisomerization of n-decane was investigated. The results indicated that the AlPO4-31 and SAPO-31 molecular sieves with pure crystal phase and higher crystallinity assigned to ATO topology structure were obtained at 170 oC for 2 h by microwave irradiation. The BET surface area and micropore volume were increased because of the introduction of Si to the framework of AlPO4-31. The distribution of Si in the framework and the acidity of the SAPO-31 molecular sieve were varied by changing the composition of the reaction mixture. The bifunctional catalyst Pd/SAPO-31 with suitable acidity showed high activity and selectivity for hydroisomerization of n-decane.

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Effect of Syngas Partial Pressure on Fischer-Tropsch Reaction Rate HUA Xin-Lei, WANG Li-Gang, XU Yong-Hua, WANG You-Qi, GAO Zi 2011, 32 (7):  1242-1249.  DOI: 10.3724/SP.J.1088.2011.01043 Abstract ( 2912 )   [Full Text(HTML)] () PDF (510KB) ( 933 )   The syngas consumption rate rCO and CH4 production rate rCH4 along a fixed-bed reactor for Fischer-Tropsch synthesis were measured via a high-throughput kinetic reactor under different inlet pressure (p0H2, p0CO). The data showed that within non-diffusion limited regime the feed ratio p0H2/p0CO is the determining variable while p0H2+CO is non-sensitive. The bed-level intrinsic rate measured under various inlet pressure can be used to establish the pellet level rate-law. The results showed that for rate law using the simple (pH2, pCO) representation the parameters for CO consumption reaction are dependent on the local conversion at pellet position along the bed.

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Effect of Acid Pretreatment of Activated Carbon (AC) on Catalytic Performance of Co-Zr-La/AC Catalysts for Higher Alcohols Production from Syngas Lü Zhao-Po, TANG Hao-Dong, LIU Cai-Lai, LIU Hua-Zhang 2011, 32 (7):  1250-1255.  DOI: 10.3724/SP.J.1088.2011.10301 Abstract ( 3346 )   [Full Text(HTML)] () PDF (525KB) ( 928 )   Activated carbon (AC) was treated with nitric acid of different concentrations prior to the preparation of Co-Zr-La/AC higher alcohol synthesis catalysts. The effect of acid pretreatment on the catalyst activity was studied. The surface properties of the samples were investigated by Boehm titration and N2 physisorption. And the Co dispersion, reduction properties, and physical structure of the catalysts were characterized by CO chemisorption, temperature-programmed reduction, and X-ray diffraction (XRD), respectively. The results show that the nitric acid pretreatment causes the surface oxygen groups on the AC surface increase significantly and the XRD peak intensities of Co and Co2C in the catalysts vary dramatically. As a result, CO conversion increases from 9.9% to 65.3%, and the selectivity for total alcohol decreases from 62.3% to 40.5%. Although total alcohol selectivity decreases after the pretreatment, the selectivity for C6+ alcohols increases from about 12.6% to 40.3% when there are suitable amounts of Co and Co2C active sites in the catalyst that is treated with 4.6 mol/L nitric acid.

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Selective Hydrogenation of Cinnamaldehyde to Cinnamyl Alcohol over Ru/ZrO2.хH2O Catalyst LIU Hong-Lei, YUAN Mao-Lin, GUO Cai-Hong, LI Rui-Xiang, FU Hai-Yan, CHEN Hua, LI Xian-Jun 2011, 32 (7):  1256-1261.  DOI: 10.3724/SP.J.1088.2011.10231 Abstract ( 3042 )   [Full Text(HTML)] () PDF (549KB) ( 978 )   A heterogeneous supported catalyst 7.5%Ru/ZrO2.хH2O was prepared by co-precipitation method and characterized by N2 adsorption-desorption, X-ray diffraction, X-ray photoelectron spectroscopy, and high resolution transmission electron microscopy. Its catalytic performance in cinnamaldehyde hydrogenation was investigated. The effects of temperature, hydrogen pressure, and solvent on the activity and selectivity for cinnamyl alcohol were tested. The results showed that the conversion of cinnamaldehyde increased with the increase in temperature and hydrogen pressure, but the product selectivity decreased. The catalyst showed better catalytic performance in a polar solvent than in a non-polar solvent. Using a mixture solvent composed of Et3N and H2O can remarkably raise the activity and the selectivity of the reaction. When the volume ratio of Et3N to H2O was 4, the temperature was 70 °C, and the reaction time was 6 h, the highest conversion (98.0%) and selectivity (85.2%) were obtained.

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Atmospheric High Frequency Discharge Plasma Jet Improved Preparation of Ni/MgO Catalyst for CO2 Reforming with CH4 QIN Pan, XU Hui-Yuan, LONG Hua-Li, RAN Yi, SHANG Shu-Yong, CHU Wei, YIN Yong-Xiang, DAI Xiao-Yan 2011, 32 (7):  1262-1268.  DOI: 10.3724/SP.J.1088.2011.10309 Abstract ( 2502 )   [Full Text(HTML)] () PDF (670KB) ( 842 )   A Ni/MgO catalyst was prepared using atmospheric high frequency discharge plasma jet. The influence of three preparation methods, the conventional method, plasma method, and plasma plus calcination method, on the catalyst activity was compared using CO2 reforming with methane as the probe reaction. The catalyst samples were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and CO2 temperature-programmed surface reaction. The results suggested that the Ni-based catalyst sample prepared by the plasma plus calcination method possessed smaller Ni particle size, higher dispersion of active components, higher low-temperature activity, and enhanced anti-coking ability. The conversions of CO2 and CH4 were 90.70% and 89.37%, respectively, and lasted for 36 h without obvious deactivation under 0.1 MPa, 36 L/(h·g) and 750 oC with n(CH4)/n(CO2) = 1.

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Effect of La2O3 Promoter on the Performance of Au/TiO2 Catalyst for Selective Hydrogenation of Cinnamaldehyde LIU Ying-Xin, MENG Ling-Fu, WEI Zuo-Jun, SHI Hong-Tao 2011, 32 (7):  1269-1274.  DOI: 10.3724/SP.J.1088.2011.10223 Abstract ( 3004 )   [Full Text(HTML)] () PDF (519KB) ( 1074 )   Using TiO2 and La2O3-doped TiO2 as supports, which were prepared by the sol-gel method, a series of Au catalysts were prepared by the deposition-precipitation method. Their catalytic performance for selective hydrogenation of cinnamaldehyde was tested and their physical and chemical properties were investigated by the techniques of N2 adsorption-desorption, X-ray diffraction, high-resolution transmission electron microscopy, temperature-programmed reduction, and X-ray photoelectron spectroscopy. The results show that a moderate amount of La2O3 (10%–15%) can obviously improve the catalytic activity and selectivity of Au/TiO2 for the hydrogenation. The presence of La2O3 in TiO2 increases its surface area, restrains the growth of TiO2 crystallites, enhances the interaction between Au and support, and makes the particle size distribution of Au crystallites more evenly. The Au on the surface of Au/TiO2 exists mainly as Au0, but on the La2O3 doped catalyst there is a small portion of Au3+ species besides Au0.

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Asymmetric Hydrogenation of Aromatic Ketones Catalyzed by L-Proline-Modified Ru-PPh3/γ-Al2O3 Catalyst XIONG Wei, LIU De-Rong, JIA Yun, QIN Rui-Xiang, QIU Hui-Dong, WANG Jin-Bo, LI Xian-Jun 2011, 32 (7):  1275-1279.  DOI: 10.3724/SP.J.1088.2011.10308 Abstract ( 2408 )   [Full Text(HTML)] () PDF (895KB) ( 987 )   The asymmetric hydrogenation of aromatic ketones catalyzed by L-proline-modified Ru-PPh3/γ-Al2O3 was investigated. The effects of reaction conditions on the asymmetric hydrogenation of acetophenone were discussed in detail. The results indicated that natural chiral compound L-proline has a good modification effect on the Ru-PPh3/γ-Al2O3 catalyst. Under the optimum conditions, the conversion of acetophenone was up to 100%, and the enantioselectivity for the formation of (R)-phenyl ethanol was 59.5%. The synergistic effect between L-proline and KOH was observed. The chiral alcohol products could be easily separated by centrifugation. The catalyst was reused several times without remarkable change of enantioselectivity.

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Shape-Selective Alkylation of Toluene with Methanol over Modified Nano-scale HZSM-5 Zeolite ZHANG Zhi-Ping, ZHAO Yan, WU Hong-Yu, TAN Wei, WANG Xiang-Sheng, GUO Xin-Wen 2011, 32 (7):  1280-1286.  DOI: 10.3724/SP.J.1088.2011.10235 Abstract ( 3326 )   [Full Text(HTML)] () PDF (521KB) ( 1155 )   Shape-selective alkylation of toluene (T) with methanol (M) was performed over Si-P-Mg-modified nano-scale HZSM-5 zeolite. The change of acidity and pore structure of the catalyst was studied by X-ray diffraction, NH3 temperature-programmed desorption, Fourier transform infrared spectroscopy, and N2 adsorption．The effects of temperature, space velocity (WHSV), and flow rate of N2 carrier gas on the reaction were investigated in a continuous flow fixed-bed reactor. Under the optimized conditions (2 h–1, 460 oC, n(T)/n(M) = n(H2O)/n(HC) = n(N2)/n(HC) = 8, where HC represents toluene and methanol), during 500 h on stream over the Si-P-Mg modified nano-scale HZSM-5 catalyst, the toluene conversion of about 10% and the selectivity to p-xylene of more than 97% were maintained, indicating that the catalyst exhibits high selectivity and good stability.

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Phosphorus Doped Pd3Fe1/C Catalysts and Their Electrocatalytic Activity for Oxygen Reduction DAI You-Zhi, LIU Jin-Bing, LIU Hong, WANG Yi, SONG Shu-Qin 2011, 32 (7):  1287-1291.  DOI: 10.3724/SP.J.1088.2011.10307 Abstract ( 2873 )   [Full Text(HTML)] () PDF (901KB) ( 917 )   Non-Pt electrocatalysts, Pd3Fe1/C, were doped with inorganic nonmetallic element phosphorus through electroless plating technique, and their electrocatalytic performance was studied. Electroless plating is an effective way to obtain P-doped Pd3Fe1/C with small particle size and high dispersion. The introduction of the P element leads to the decreased Pd-Fe particle size of the catalysts and an increased electrocatalytic activity for oxygen reduction. Moreover, the P dopant can improve the stability of Pd3Fe1/C to some extent. In the case of Fe/P molar ratio = 1/10, the Pd3Fe1P10/C catalyst exhibits the best performance.