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Chinese Journal of Catalysis
2011, Vol. 32, No. 6
Online: 21 June 2011


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The tutorial review on pages 879–890 discusses the storage of solar energy in chemicals such as H₂ and alcohols by water photolysis and CO₂ photoreduction. The products can be used directly as clean and renewable fuels and chemical feedstock. The fundamental mechanisms underlying this photochemical process are discussed based on published data, and the elements influencing these reactions are also analyzed in detail.

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Table of Contents for Vol.32 No. 6 2011, 32 (6):  0-0.  Abstract ( 1287 )   PDF (1606KB) ( 855 )

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Conversion of Solar Energy to Fuels by Inorganic Heterogeneous Systems Kimfung LI, David MARTIN, Junwang TANGa 2011, 32 (6):  879-890.  DOI: 10.1016/S1872-2067(10)60209-4 Abstract ( 3772 )   [Full Text(HTML)] () PDF (275KB) ( 2495 )   Over the last several years, the need to find clean and renewable energy sources has increased rapidly because current fossil fuels will not only eventually be depleted, but their continuous combustion leads to a dramatic increase in the carbon dioxide amount in atmosphere. Utilisation of the Sun’s radiation can provide a solution to both problems. Hydrogen fuel can be generated by using solar energy to split water, and liquid fuels can be produced via direct CO2 photoreduction. This would create an essentially free carbon or at least carbon neutral energy cycle. In this tutorial review, the current progress in fuels’ generation directly driven by solar energy is summarised. Fundamental mechanisms are discussed with suggestions for future research.

Research papers

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Research Progress on Solid Superbase Catalysts in the Last Decade WEI Yu-Dan, ZHANG Shu-Guo, LI Gui-Sheng, YIN Shuang-Feng, QU Ze-Tang 2011, 32 (6):  891-898.  DOI: 10.3724/SP.J.1088.2011.10206 Abstract ( 3950 )   [Full Text(HTML)] () PDF (605KB) ( 2197 )   This review focuses on the research progress on solid superbase catalysts in recent decade, including the type and preparation of superbases, the mechanism for basic site generation, and the application of superbases in catalysis. It is pointed out that only several kinds of superbases have been reported so far, and the majority of solid superbases are generated using metal oxides as supports. The reported superbases are very sensitive to H2O and CO2, and rigorous conditions are required for their preparation and utilization. As a consequence, the development and application of solid superbases are restricted. Despite the understanding of the formation mechanism of superbasic sites is essential for the design of solid superbases, reports on this aspect are few. It is necessary to develop new support materials or modifying agents to generate solid superbases of novelty. Efforts should be devoted to the study of the generation mechanism of superbasic sites by adopting advanced characterization techniques and new methods for theoretical investigation. Moreover, it can be predicted that solid superbases will find new application in catalysis, especially in reactions that require high temperatures for desorption of acidic substances from the surface of superbases.

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Chiral Primary Amine Organocatalysts for Syn-selective Asymmetric Cross-Aldol Reactions GAO Qiang, LIU , LU Sheng-Mei, LI Can- 2011, 32 (6):  899-903.  DOI: 10.1016/S1872-2067(10)60237-9 Abstract ( 3007 )   [Full Text(HTML)] () PDF (467KB) ( 1586 )   Based on the “acid-base” interaction strategy, organocatalysts for the asymmetric cross-aldol reaction were synthesized by the in situ combination of chiral primary amines with protonic acids. Unlike general secondary amine catalysts that give anti-selective products, as-prepared primary amine catalysts can give syn-selective cross-aldol products with high yield and high selectivity (up to 90% yield, 90:10 syn/anti ratio, 90% ee). Compared with the complex synthesis of the reported catalysts, the primary amine catalyst that gave the best results was easily prepared using commercial available (1S,2S)-(+)-cyclohexanediamine.

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Room Temperature Catalytic Ozonation of Toluene over MnO2/Al2O3 LONG Li-Ping, ZHAO Jian-Guo, YANG Li-Xian, FU Ming-Li, WU Jun-Liang, HUANG Bi-Chun, YE Dai-Qi 2011, 32 (6):  904-916.  DOI: 10.1016/S1872-2067(10)60216-1 Abstract ( 3877 )   [Full Text(HTML)] () PDF (674KB) ( 1932 )   Five kinds of transition metal oxides supported on alumina and prepared by wetness impregnation were evaluated for the catalytic ozonation of toluene at room temperature and characterized by temperature-programmed reduction, temperature-programmed oxidation, N2 adsorption-desorption, and X-ray photoelectron spectroscopy. The catalysts with a lower reduction temperature and less H2 consumption showed a higher efficiency for ozone and toluene decomposition, such as NiO/Al2O3, CoO/Al2O3, and MnO2/Al2O3, while lower efficiency were observed on Fe2O3/Al2O3 and CuO/Al2O3. Toluene decomposition efficiency was obviously dependent on ozone. Because of the low ozone to toluene concentration ratio, a CO2 yield of less than 30% was obtained. At a toluene concentration of 666 mg/m3 and an ozone concentration between 193 and 965 mg/m3, toluene conversion was found to vary from 15.2% to 46.7%. Additionally, we observed an increase in oxidation products and lattice oxygen on the catalyst surface. A preliminary investigation into the reaction pathway was undertook by in situ diffuse reflectance Fourier transform infrared spectroscopy. With regards to the formation of COO-, C=O, and C–O groups the high ozone concentration accelerated the transformation from COO- to C=O and C–O. The substance containing COO- remained unchanged at 573 K, while the substances containing C=O and C–O underwent oxidation at higher than 373 K. A possible reaction pathway is proposed based on these findings.

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Preparation of Highly Loaded and Active Ni/Al2O3 Catalysts for the Hydrogenation of Aromatic Rings HU Sheng-Hua, XUE Ming-Wei, CHEN Hui, SUN Yin-Lu, SHEN Jian-Yi 2011, 32 (6):  917-925.  DOI: 10.1016/S1872-2067(10)60224-0 Abstract ( 3566 )   [Full Text(HTML)] () PDF (782KB) ( 1098 )   Highly loaded and dispersed Ni/Al2O3-B catalysts were prepared by the co-precipitation method with an n-butanol drying process. The loading of nickel and drying process were found to be the two key factors in determining the surface area and pore structures of catalysts as well as the reducibility and dispersion of supported nickel. The 80%Ni/Al2O3-B treated with n-butanol during the drying process exhibited the high surface area and high reducibility and dispersion of supported nickel, leading to the high active nickel surface area (90 m2/g-catalyst). It adsorbed toluene strongly and thus exhibited high activity for the hydrogenation of aromatic rings in toluene and phenol.

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Fabrication and Characterization of Tailored TiO2 and WO3/MWCNT Composites for Methylene Blue Decomposition ZHU Lei, MENG Zeda, OH WonChun 2011, 32 (6):  926-932.  DOI: 10.1016/S1872-2067(10)60208-2 Abstract ( 3271 )   [Full Text(HTML)] () PDF (594KB) ( 1462 )   A sol-gel method was used to prepare WO3/MWCNT-TiO2 composites. Their photocatalytic activities were evaluated by the degradation of methylene blue (MB) solution under UV light. The catalysts were characterized by X-ray diffraction, specific surface area measurement, energy-dispersive X-ray analysis, transmission and scanning electron microscopy. Aqueous MB solutions of 100 ml were photodegraded by a small amount of the WO3/MWCNT-TiO2 composite under UV light irradiation. The photocatalytic data showed that the WO3/MWCNT-TiO2 composite achieved a high rate of MB photodegradation. This was attributed to the use of MWCNT which can absorb UV light to create photo-induced electrons, strong adsorption of dye molecules on the photocatalyst, and reduced recombination rate of electron-holes in the WO3/MWCNT-TiO2 composite due to the introduction of the WO3 semiconductor.

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Microwave-Assisted Preparation of CdS Nanoparticles in a Halide-Free Ionic Liquid and Their Photocatalytic Activities M. ESMAILI, A. HABIBI-YANGJEH 2011, 32 (6):  933-938.  DOI: 10.1016/S1872-2067(10)60217-3 Abstract ( 2655 )   [Full Text(HTML)] () PDF (398KB) ( 1369 )   A microwave-assisted (4–6 min) method was used for the preparation of CdS nanoparticles in 1-ethyl-3-methylimidazolium ethyl sulfate, a halide-free room-temperature ionic liquid (RTIL). The samples were characterized by powder X-ray diffraction, energy dispersive X-ray spectroscopy, and scanning electron microscopy. Diffuse reflectance spectra showed a 1.33 eV blue shift relative to bulk CdS. The photocatalytic activities of the nanoparticles for photodegradation of methylene blue (MB) using UV and visible light were measured. The photodegradation of MB decreased with calcination temperature. First order rate constants for the reaction under visible and UV irradiations over the nanoparticles prepared in the RTIL rich media were 5.4 and 2.5 higher, respectively, than the sample prepared in water.

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Morphology-Dependent Photocatalytic Performance of Monoclinic BiVO4 for Methyl Orange Degradation under Visible-Light Irradiation JIANG Hai-Yan, DAI Hong-Xing, MENG Xue, ZHANG Lei, DENG Ji-Guang, JI Ke-Meng 2011, 32 (6):  939-949.  DOI: 10.1016/S1872-2067(10)60215-X Abstract ( 4564 )   [Full Text(HTML)] () PDF (1014KB) ( 1775 )   Monoclinic BiVO4 with multiple morphologies were fabricated using the alcoho-hydrothermal strategy with bismuth nitrate and ammonium metavanadate as inorganic sources, NaOH for pH adjustment, and the triblock copolymer P123 as a surfactant. The materials were characterized by X-ray diffraction, nitrogen adsorption-desorption, scanning electron microscopy, X-ray photoelectron spectroscopy, and ultraviolet-visible diffuse reflectance spectroscopy. The photocatalytic performance of the BiVO4 samples was evaluated for the degradation of methyl orange (MO) under visible-light irradiation condition. The results showed that the surfactant and pH had a significant influence on the particle morphology of the BiVO4 product. Porous spherical, flower-like, and sheet-like BiVO4 were fabricated at an alcoho-hydrothermal temperature of 180 °C and at a pH of 2, 7, or 10, respectively, whereas rod-like BiVO4 was obtained in the presence of P123 at an alcoho-hydrothermal temperature of 180 °C and at a pH of 2. The difference in BiVO4 particle morphology led to differences in surface area, surface oxygen vacancy density, and (040) crystal plane exposure. Among the four BiVO4 samples, the rod-like sample had the highest surface area, surface oxygen vacancy density, and (040) crystal plane exposure, and the lowest bandgap energy resulting in it having the best photocatalytic activity for MO photodegradation. It can be concluded that a morphological effect is responsible for the photocatalytic performance and the rod-like morphology seems to favor an enhancement in the photocatalytic performance of the BiVO4 material.

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Preparation of Nano-Cu2O/Pearl Shell Composites for Treating Organic Dyes ZOU Xiao-Lan, YU Yan-Qing, LI Chao-Feng, ZHU Xiao-Bin 2011, 32 (6):  950-956.  DOI: 10.1016/S1872-2067(10)60231-8 Abstract ( 2937 )   [Full Text(HTML)] () PDF (572KB) ( 1032 )   Waste pearl shells were activated and used as carriers to prepare a nano-Cu2O/pearl shell composite photocatalyst by in situ hydrolysis. The composites were characterized by X-ray diffraction, X-ray photoelectron spectrometer, scanning electron microscopy, and UV-Vis diffuse reflectance spectrometer. Reactive red dye B-3G solutions were used as simulate wastewater to investigate the photocatalytic performance under visible light irradiation. The loaded Cu2O particles had an average diameter of 16.8 nm, were oval in shape and have absorption bands in the UV and visible region similar to those of pure Cu2O particles. The nano-Cu2O/pearl shell composites had much higher photocatalytic activities than pure Cu2O. Over 98% of the B-3G solutes were decolorized by these composites under the conditions of pH = 6.0–12.0, reaction time = 90 min, and B-3G concentration ≤ 220 mg/L. The photocatalytic decolorization of B-3G followed pseudo-first order kinetics. The formation mechanism of the nano-Cu2O/pearl shell composites was studied by Fourier transform infrared spectroscopy. It involved the interaction and combination of Cu2O and CaO.

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Cu/SiO2 Catalysts Prepared by the Sol-Gel Method for Hydrogenation of Dimethyl Oxalate to Ethylene Glycol LIN Ling, PAN Peng-Bin, ZHOU Zhang-Feng, LI Zhao-Ji, YANG Jin-Xia, SUN Ming-Ling, YAO Yuan-Gen 2011, 32 (6):  957-969.  DOI: 10.1016/S1872-2067(10)60223-9 Abstract ( 3481 )   [Full Text(HTML)] () PDF (1260KB) ( 1752 )   A series of Cu/SiO2 catalysts for the hydrogenation of dimethyl oxalate to ethylene glycol were prepared by the sol-gel method. Under optimized hydrogenation conditions, dimethyl oxalate conversion and ethylene glycol selectivity were found to reach 99.9% and 95.0%, respectively, upon varying the copper loading between 15% and 25%. The prepared catalysts were characterized by N2-physisorption, transmission electron microscopy, X-ray diffraction, H2-temperature-programmed reduction, N2O titration, and X-ray photoelectron spectroscopy. The results show that when the copper loading was increased under the same experimental conditions the factors that mostly affect the activities of the catalysts prepared by the sol-gel method are encapsulation and agglomeration. The encapsulation of silica is strong and it becomes the major factor when w(Cu) ≤ 10% while agglomeration among the copper species on the catalyst surface becomes more serious and is a major factor when w(Cu) > 10%. These two factors influence the surface structure, the morphology of the copper species, and the chemicals surroundings the catalysts and as a result the performance of the catalysts is affected too.

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Steam Reforming of Ethanol over Zn-Doped LaCoO3 Perovskite Nanocatalysts MA Fei, CHU Wei, HUANG Li-Hong, YU Xiao-Peng, WU Yong-Yong 2011, 32 (6):  970-977.  DOI: 10.1016/S1872-2067(10)60218-5 Abstract ( 3598 )   [Full Text(HTML)] () PDF (666KB) ( 1141 )   Nanostructured LaCo1-xZnxO3 (x = 0, 0.05, 0.1, 0.2, 0.3 and 0.5) perovskites were synthesized by a one-step citric acid-complexing method for hydrogen production by the steam reforming of ethanol. For comparison, 8% CoO/ZnO and 8% CoO/La2O3 were prepared by impregnation and evaluated. The catalyst samples were characterized by X-ray diffraction, temperature-programmed reduction, and X-ray photoelectron spectroscopy. The results indicated that zinc did not favor the formation of the LaCo1-xZnxO3 perovskite and the structures of the substituted samples were stronger than that of LaCoO3. Some segregation was observed for x ≥ 0.1. The reactivity of the studied samples was sensitive to the zinc content and lower substitution values were found to be better. An unexpected phase (Co3O4) appeared in the fresh LaCo0.9Zn0.1O3 sample. The presence of the Co3O4 phase increased the reactivity toward hydrogen production by the steam reforming of ethanol. The presence of La2O2CO3 is responsible for the low carbon deposition and the CH4 selectivity in the aged samples.

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Photocatalytic Synthesis of Gold Nanoparticles Using Preyssler Acid and Their Photocatalytic Activity Ali AYATI, Ali AHMADPOUR, Fatemeh F. BAMOHARRAM, Majid M. HERAVI, Hamed RASHIDI 2011, 32 (6):  978-982.  DOI: 10.1016/S1872-2067(10)60221-5 Abstract ( 3680 )   [Full Text(HTML)] () PDF (554KB) ( 1105 )   Preyssler acid H14[NaP5W30O110] was used as reducing agent and stabilizer for the synthesis of gold nanoparticles by photolysis of Au(III)/Preyssler acid/propan-2-ol solution. Preyssler acid plays both the role of transferring electrons from propan-2-ol to Au(III) and stabilizing the nanoparticles. Propan-2-ol was used as sacrificial reagent for the photoformation of reduced Preyssler acid. Gold nanoparticles (Au NPs) were characterized by UV-Vis spectroscopy, transmission electron microscopy (TEM), and particle size distribution (PSD) measurements. The synthesized Au NPs had a uniform hexagonal morphology and their size was about 17 nm. The catalytic performance of these NPs for photodegradation of methyl orange (MeO) was investigated in aqueous solution. UV-Vis studies showed that Au NPs can catalyze photodegradation of this azo dye. The pseudo-first-order rate constants were also calculated for this reaction.

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Photocatalytic Degradation of Rhodamine B on Anatase, Rutile, and Brookite TiO2 ZHANG Jing, YAN Song, FU Lu, WANG Fei, YUAN Meng-Qiong, LUO Gen-Xiang, XU Qian, WANG Xiang, LI Can 2011, 32 (6):  983-991.  DOI: 10.1016/S1872-2067(10)60222-7 Abstract ( 3911 )   [Full Text(HTML)] () PDF (694KB) ( 1359 )   This study compared the photocatalytic activities for the degradation of Rhodamine B (RhB) in aqueous solutions of anatase, rutile, and brookite TiO2. The TiO2 powders were prepared at low temperature. As compared with rutile obtained by a conventional high temperature calcination, the rutile TiO2 prepared by the low temperature route had a smaller particle size, higher surface area, and more surface hydroxyl groups, and it gave a high photocatalytic activity. Rutile gave a faster photocatalysis reaction rate than anatase TiO2 for the same particle size and surface area. A pure brookite phase showed a lower photocatalytic activity when this was expressed in moles converted RhB per hour than the anatase and rutile phases. However, its areal photocatalytic activity expressed in moles converted RhB per hour per surface area was much higher than that of anatase and rutile TiO2.

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Aromatization of Mixed C4 Hydrocarbons over the Binderless Zn/ZSM-5 Catalyst LI Yu-Ning, REN Li-Ping, LI Ya-Nan, JIN Zhao-Sheng, TENG Jia-Wei, YANG Wei-Min 2011, 32 (6):  992-996.  DOI: 10.3724/SP.J.1088.2011.10107 Abstract ( 3642 )   [Full Text(HTML)] () PDF (538KB) ( 1128 )   Four Zn/ZSM-5 catalyst samples were prepared by mechanical pressing, introducing binder of aluminum oxide, introducing binder of silicon oxide, and binderless molding, respectively. The samples were characterized by N2 physical adsorption, scanning electron microscopy, NH3 temperature-programmed desorption, pyridine Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy and were evaluated by aromatization of mixed C4 hydrocarbons. The results indicated that, compared with the mechanical pressed catalyst and the shaped catalyst samples with binders, the binderless Zn/ZSM-5 sample possessed higher specific surface area, accommodated more Zn species inside the zeolite crystals, and showed better catalytic performance in the aromatization of mixed C4 hydrocarbons.

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Dehydration of Glucose and Fructose into 5-HMF Catalyzed by Lewis Acid in Ionic Liquids TIAN Yu-Kui, DENG Jin, PAN Tao, GUO Qing-Xiang, FU Yao 2011, 32 (6):  997-1002.  DOI: 10.3724/SP.J.1088.2011.01258 Abstract ( 4522 )   [Full Text(HTML)] () PDF (437KB) ( 1777 )   A variety of Lewis acids have been examined for the transformation of glucose and fructose into 5-hydroxymethylfurfural (5-HMF) in ionic liquids (ILs). SnCln and CrCln are effective catalysts for the isomerization, and Lewis acids with strong acidity can facilitate the dehydration of fructose. The influence of ILs’ structure, including the length of alkyl side chain and halide anions, on the conversion was also studied. A distinct odd-even carbon-atom-number effect is observed in the conversion of glucose to 5-HMF and the imidazolium bromides with short alkyl side-chains can provide a higher yield of 5-HMF from fructose. In the presence of 1-ethyl-3-methylimidazolium bromide ([C2MIM]Br) and SnCl2, the yields of 5-HMF are 65% and 73% from glucose and fructose, respectively.

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Asymmetric Biosynthesis of (S)-1-(4-Methoxyphenyl)ethanol in Various Reaction Systems WANG Wei, ZONG Min-Hua, LOU Wen-Yong 2011, 32 (6):  1003-1010.  DOI: 10.3724/SP.J.1088.2011.10112 Abstract ( 3239 )   [Full Text(HTML)] () PDF (576KB) ( 789 )   The biocatalytic enantioselective reduction of 4-methoxyacetophenone to (S)-1-(4-methoxyphenyl)ethanol was studied. The efficiency of the reaction was improved to different extents when an ionic liquid-containing co-solvent system and an ionic liquids/bufffer biphasic system were used. The catalytic performance of the biocatalyst depended not only on the types of the anions and cations in the ionic liquids but also on their combination.

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Effects of Acid Treatment of Activated Carbon on Catalytic Performance of RbNO3-KF/AC Catalyst for C2F5I Gas-Phase Synthesis MAO Ai-Qin, WANG Hua, TAN Ling-Hua, LIN Xiang-Yang, PAN Ren-Ming 2011, 32 (6):  1011-1016.  DOI: 10.3724/SP.J.1088.2011.01235 Abstract ( 2817 )   [Full Text(HTML)] () PDF (560KB) ( 936 )   Modification of activated carbon (AC) with different acid solution might result in various surface oxygen groups, which can enhance the anchoring interaction between AC support and metal precursor and change the dispersion and basicity of the catalyst. The influence of HCl, HNO3, and HF treatment on RbNO3-KF/AC catalyst in the gas-phase synthesis of C2F5I by reaction of C2HF5 with I2 and O2 was studied. The pore structure and the surface chemical properties of the AC support were investigated by N2 adsorption-desorption and Boehm titration. The dispersion and basicity of the catalyst before and after acid treatment were investigated by CO2 temperature-programmed desorption, X-ray diffraction, X-ray photoelectron spectroscopy, and inductively coupled plasma atomic emission spectrometry. It was found that after the HCl treatment, the RbNO3-KF/AC(HCl) catalyst has high dispersion and moderately basicity, which is helpful for the enhancement of catalytic activity for C2F5I synthesis. The catalyst dispersion is in the order: RbNO3-KF/AC(HNO3) > RbNO3-KF/AC(HF) > RbNO3-KF/AC(HCl) > RbNO3-KF/AC. The same sequence is also observed for the amount of acid surface oxygen groups on AC, but not for the weak basicity of the catalyst. The key role of acid treatment on the AC surface chemistry and moderate basic sites, which are closely related to catalyst dispersion and basicity, is examined to rationalize these findings.

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Synthesis Gas from Pyrolysis of Cedar Sawdust as Biomass Materials: Characterization and Catalytic Performance of Nickel-Based Monolithic Catalyst LU Min, Lü Peng-Mei, YUAN Zhen-Hong, LI Hui-Wen, XU Jing-Liang 2011, 32 (6):  1017-1021.  DOI: 10.3724/SP.J.1088.2011.10139 Abstract ( 2657 )   [Full Text(HTML)] () PDF (493KB) ( 835 )   A series of monolithic catalysts with different NiO loadings were prepared by supported on the acid treated cordierite. Their specific surface area, pore volume, pore distribution, and catalytic performance in the reforming reaction of biomass pyrolysis gas for synthesis gas were studied. The results show that the specific surface area and pore volume of the cordierite after acid treatment are up to 156 m2/g and 0.099 m3/g respectively. However, with increasing nickel oxide loading, the specific surface area and pore volume of the catalyst decrease greatly and then tend to steady. The effect of nickel oxide loading on gas composition is quite small, and the total content of H2 and CO is maintained at 90%. The tar conversion is not affected by the specific surface area of the catalysts. After 6 h catalytic reaction, the structure of the catalysts with 28% NiO does not change, and the quantity of carbon deposition is about 1%. The tar conversion decreases from 87.4% to 81.3%. It is suggested that the nickel-based catalyst has relatively stable activity under high tar concentration conditions, which is attributed to the high dispersion of nickel particles on the support and high stability of the catalyst phase structure.

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Propane Selective Oxidation to Acrylic Acid over Combined Catalysts FANG Wen, GE Qing-Jie, YU Jia-Feng, XU Heng-Yong 2011, 32 (6):  1022-1026.  DOI: 10.3724/SP.J.1088.2011.10136 Abstract ( 2731 )   [Full Text(HTML)] () PDF (489KB) ( 748 )   A double-layer catalyst, containing a NiZrO catalyst for propane oxidative dehydrogenation and a Mo-based mixed metal oxide catalyst for propylene selective oxidation, was applied to propane selective oxidation to acrylic acid. The composition of the combined catalyst was first adjusted. When the mass ratio of the two components was 1:1, a maximum acrylic acid yield was achieved. The effects of reaction conditions were studied, including temperature, space velocity, V(C3H8)/V(O2) ratio, and N2 content. Based on the use of an O2-distributor, the stability test was carried out. During 30 h operation at 340 oC, propane conversion and acrylic acid selectivity remained at ~20% and ~74%, respectively.

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Preparation and Characterization of Co-Based Catalyst via Dielectric-Barrier Discharge Plasma Decomposition for Fischer-Tropsch Synthesis HUANG Cheng-Du, BAI Su-Li, Lü Jing, LI Zhen-Hua 2011, 32 (6):  1027-1034.  DOI: 10.3724/SP.J.1088.2011.10116 Abstract ( 2990 )   [Full Text(HTML)] () PDF (727KB) ( 1078 )   To obtain a highly dispersed Co-based catalyst, dielectric-barrier discharge (DBD) plasma instead of calcination was used to decompose the precursors at low temperature. It was found that DBD plasma can not only replace calcination to get catalyst precursor decomposed but also be quicker and more energy-saving. The catalyst samples treated by the two methods had similar surface area, while pore volume and pore size of the sample treated by DBD was larger than that by calcination. Temperature-programmed reduction results showed that the catalyst treated by DBD resulted in higher Co dispersion and stronger interaction between Co and the support than that by calcination. X-ray diffraction results indicated that Co3O4 was the main Co species after DBD treatment. The Co3O4 crystallite diameter was 11.8 nm, which was smaller than that of calcined counterparts. Transmission electron microscopy results proved that DBD treatment resulted in smaller Co oxide clusters, more homogeneous Co distribution, and less agglomeration. Fischer-Tropsch synthesis performance evaluation results showed that DBD treated catalyst had higher CO conversion and C5+ selectivity than the calcined one.

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Asymmetric Reduction of Ethyl Pyruvate Catalyzed by Yeast Resting Cells to (S)-Ethyl Lactate WANG Dan, ZHANG Qiang, LI Wang, QI 南Chang, GUO Chun-Xiao, YANG Zhi-Rong, ZHANG Jie 2011, 32 (6):  1035-1039.  DOI: 10.3724/SP.J.1088.2011.01236 Abstract ( 2964 )   [Full Text(HTML)] () PDF (510KB) ( 896 )   Thirty six strains that exhibited the catalytic activity for asymmetric reduction of ethyl pyruvate to (S)-ethyl lactate were isolated from sewage of a chemical factory in Chengdu, China and the neighboring soil. Among them, yeast strain BTY18-6 has high catalytic activity. The asymmetric reduction of ethyl pyruvate to (S)-ethyl lactate catalyzed by BTY18-6 resting cells in an aqueous phase was examined, and the parameters influencing the bio-reduction were optimized. The results showed that, under the optimized conditions of 2.5% glucose as co-substrate, the initial reaction pH = 6.8, the initial cell concentration at 0.175 g/ml (wet mass) cultured for 48 h, the initial ethyl pyruvate concentration at 65 mmol/L, temperature 32 oC, and reaction time 48 h, the ethyl pyruvate conversion reached 95.5% with enantiomeric excess of 92.1%.

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Ground-Level Ozone Decomposition over Pd-MnOx/Al2O3 Catalyst Prepared by Urea Hydrolysis PAN Hao, ZHOU Li-Na, ZHU Yi, PENG Na, GONG Mao-Chu, CHEN Yao-Qiang 2011, 32 (6):  1040-1045.  DOI: 10.3724/SP.J.1088.2011.10145 Abstract ( 3134 )   [Full Text(HTML)] () PDF (531KB) ( 1176 )   The Pd-MnOx/Al2O3 catalyst has been prepared by the urea hydrolysis method and characterized by low temperature nitrogen adsorption-desorption and X-ray diffraction. Its catalytic activity for decomposing ground-level ozone has been studied. The catalyst showed a high activity at low temperature and high relative humidity. At gas hourly space velocity (GHSV) of 660000 h-1 and relative humidity of 85%–90%, the ozone conversion over the catalyst reached 91.7% at 20 °C and the temperature for complete decomposition of ozone was only 24 °C. Furthermore, the prepared catalyst can completely decompose ground-level ozone when it is coated on the wave shaped heat patches of automobile water tanks.

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Theoretical Study of the Adsorption of Formaldehyde on Perfect and S-Deficient FeS2(100) Surfaces DU Yu-Dong, GUO Xin, CHEN Wen-Kai, LI Yi, ZHANG Yong-Fan 2011, 32 (6):  1046-1050.  DOI: 10.3724/SP.J.1088.2011.01251 Abstract ( 3008 )   [Full Text(HTML)] () PDF (626KB) ( 912 )   The adsorption of HCHO molecules on perfect and S-deficient FeS2(100) surfaces was studied with a periodic slab model by Perdue-Burke-Ernzerhof approach of General Gradient Approximation within the framework of the density functional theory. The calculated results show that HCHO reacted with both surfaces through the O atom. HCHO adsorbed aslant on the Fe-top site on the perfect surface, while there were two stable structures for HCHO on the S-deficient surface, where HCHO bonded with one and two fourfold-coordinate Fe cations, respectively. The calculation of density of states, Mulliken population, and vibrational frequencies of the adsorption systems indicated that the electrons transferred from the substrate to HCHO, and the bond of C=O was elongated and weakened.

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Biocatalytic Synthesis of Salidroside by β-Glucosidase in Ionic Liquids WANG Meng-Liang, GUO Chun-Xia 2011, 32 (6):  1051-1055.  DOI: 10.3724/SP.J.1088.2011.01211 Abstract ( 3243 )   [Full Text(HTML)] () PDF (495KB) ( 998 )   β-Glucosidase modified with polyethylene glycol (PEG) was used as catalyst for the synthesis of salidroside from tyrosol and D-glucose, and its catalytic activity in three ionic liquids, [bmim]PF6, [bmim]BF4, and [bmim]Tf2N, and two common organic solvents, 1,4-dioxane and n-hexane, was measured. Ionic liquid [bmim]PF6 was the optimal reaction medium, and different reaction conditions were optimized in it. A yield of 88.5% (product content of 61.93 mmo1/L) was obtained under the conditions of H2O content of 2%, temperature of 50 oC, tyrosol content of 70 mmo1/L, D-glucose/tyrosol molar ratio of 2, and reaction time of 24 h. The results suggest that both the modification with PEG and using ionic liquid [bmim]PF6 as reaction medium have obvious promoting effects on the enzymatic synthesis of salidroside.

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Density Functional Theory Study of Ethylene Protonation over HZSM-5 Zeolite with Neighboring Brönsted Acid Sites REN Jue, ZHOU Dan-Hong, LI Jing-Hong, CAO Liang, XING Shuang-Ying 2011, 32 (6):  1056-1062.  DOI: 10.3724/SP.J.1088.2011.10110 Abstract ( 2955 )   [Full Text(HTML)] () PDF (480KB) ( 845 )   By the density functional theory method, the effect of different acid sites and neighboring acid sites on ethylene protonation over HZSM-5 zeolite was investigated. The calculations were based on the 20T cluster model and carried out at the B3LYP/6-31G(d,p) theoretical level. The structure, atomic charges, and the energy of the ethylene adsorption species, transition state, and the surface alkoxide products were examined. The results indicated that the next-nearest-neighboring acid sites led to obvious decrease in acid strength and adsorption energy but slight decrease in activation energy, while the next-next-nearest-neighboring acid sites had a very slender effect on acid strength and the affection on ethylene protonation could be neglected. The activation energy and reaction energy had no inevitable correlation with the acid strength but virtually depended on the location and chemical environment of the acid sites in HZSM-5 zeolite. If the transition-state structure is much resembling to the carbenium ion, the activation energy would be higher.

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Regioselective Galactosylation of Floxuridine Catalyzed by β-Galactosidase from Bovine Liver in Co-solvent Systems YE Min, LIU Qiu-Ping, LI Ning, ZONG Min-Hua 2011, 32 (6):  1063-1068.  DOI: 10.3724/SP.J.1088.2011.01150 Abstract ( 3067 )   [Full Text(HTML)] () PDF (514KB) ( 1013 )   The influence of organic solvents and their contents on the regioselective galactosylation of floxuridine catalyzed by β-galactosidase from bovine liver was investigated in co-solvent systems. It was revealed that the enzyme was unstable and inactivated substantially in organic solvent (10%, v/v)-containing systems, and the detrimental impacts of organic solvents on the enzyme could be relieved remarkably by decreasing their contents. Nevertheless, the addition of organic solvents exerted no influence on the regioselectivity of the enzymatic glycosylation, which retained >99%. The catalytic performance of β-galactosidase from bovine liver correlated well with the dielectric constants of organic solvents in co-solvent systems, among which the enzyme displayed the highest activity in dimethyl sulfoxide (DMSO)-containing system. The yield of desired product reached 71% when the DMSO content was less than 5% (v/v) in the medium.

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Preparation of Cu-Mn/Zr-Ce-SBA-15 Catalyst with Short Mesochannels and Its Catalytic Performance for Toluene Combustion YUAN Jin-Fang, LI Jian-Sheng, WANG Fang, SUN Xiu-Yun, SHEN Jin-You, HAN Wei-Qing, WANG Lian-Jun 2011, 32 (6):  1069-1075.  DOI: 10.3724/SP.J.1088.2011.10122 Abstract ( 4077 )   [Full Text(HTML)] () PDF (1031KB) ( 1287 )   The mesoporous Zr-Ce-SBA-15 (ZCS) material with short mesochannels was synthesized through a hydrothermal route. A series of Cu-Mn/ZCS catalyst samples with different Cu/Mn ratios and Cu-Mn contents were prepared by impregnation. The structure of the catalyst samples was characterized by N2 adsorption-desorption, transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The catalytic performance of the catalyst for toluene combustion was evaluated in a fixed-bed microreactor. The results reveal that the Cu-Mn/ZCS catalyst has unique hexagonal platelet morphology and possesses highly ordered two-dimensional hexagonal mesoporous structure with short channels (0.4–0.5 μm). The specific surface area, pore volume, and pore diameter of the 20%Cu-Mn/ZCS are 296 m2/g, 0.42 cm3/g, and 6.4 nm, respectively. Compared with 20%Cu-Mn/SBA-15 with longer channel length (1–2 μm), the temperature of 95% toluene conversion (T95) over 20%Cu-Mn/ZCS decreases from 284 to 270 oC, indicating that the short channeled Cu-Mn/ZCS catalyst possesses higher catalytic activity than that over Cu-Mn/SBA-15.

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Photo-sensitized Degradation of Dye Pollutants on Amorphous TiO2 under Visible Light Irradiation WANG Qi, ZHAO Jin-Cai, CONG Yan-Qing, ZHANG Yi 2011, 32 (6):  1076-1082.  DOI: 10.3724/SP.J.1088.2011.10336 Abstract ( 3944 )   [Full Text(HTML)] () PDF (598KB) ( 2097 )   Amorphous TiO2 (Am-TiO2) was prepared via a simple step through hydrolysis. The as-prepared Am-TiO2 was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, UV-visible diffuse reflectance spectroscopy, and N2 adsorption-desorption. Large surface area (216 m2/g) and abundant surface hydroxyl group/chemical adsorbed water were observed on Am-TiO2. Compared with crystallized TiO2, the adsorption edge of Am-TiO2 exhibited a blue shift (from 411 to 378 nm). Rapid photo-sensitized degradation of rhodamine B (RhB) was achieved on Am-TiO2 under visible light (λ > 420 nm) irradiation. The pseudo-first-order rate constant (k = 0.0325 min-1) was 6.5 and 5.2 times that of anatase and TiO2 P25, respectively. Moreover, both the N-deethylation and cleavage of chromophore ring structure of RhB were observed on Am-TiO2 while only the latter path predominated on crystallized TiO2. The difference between cleavage of chromophore ring structure and N-deethylation was ascribed to different anchoring groups of RhB on TiO2 through –COOH and –N+Et2, respectively. Testing in 4 recycle experiments, the degradation rate of RhB did not change significantly, indicating the excellent stability and reusability of the Am-TiO2 photocatalyst.