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Chinese Journal of Catalysis
2008, Vol. 29, No. 1
Online: 25 January 2008

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Synthesis of Superhydrophobic Surface of Polyethylene via in Situ Ziegler-Natta Polymerization ZHANG Chunyu;CAI Hongguang;CHEN Bin;DONG Weimin;MU Zhiyuan;ZHANG Xuequan* 2008, 29 (1):  1-3.  Abstract ( 2097 )   [Full Text(HTML)] () PDF (200KB) ( 1899 )   A new strategy for fabricating polyethylene (PE) superhydrophobic surface by utilizing the feature of “morphology duplicating effect” of Ziegler-Natta catalyst was investigated. The Ziegler-Natta catalyst components (MgCl2 and TiCl4) were first intercalated in between the montmorillonite (MMT) gallery and then the PE/MMT nanocomposite was prepared via in situ Ziegler-Natta polymerization. The surface morphology of PE/MMT was highly rough with a petal-like microstructure. The film made from such nanocomposite has the superhydrophobic performance with a water contact angle of (152.2±0.8)° without any modification by the low surface free energy material.

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Catalytic Activity of Co-HMS Modified by Organic Groups for Cyclohexane Oxidation CHEN Chen;ZHANG Qiaohong;MA Hong;GAO Jin;SUN Zhiqiang;XU Jie* 2008, 29 (1):  4-6.  Abstract ( 1982 )   [Full Text(HTML)] () PDF (169KB) ( 874 )   By a one-step co-condensation route using hexadecylamine as the template, various organic groups were successfully immobilized on the surface of hexagonal mesoporous silicas (HMS) along with Co2+ions incorporated into the framework. The obtained bifunctionalized materials showed high activity in the selective oxidation of cyclohexane. The Co2+cations were active for oxidation while the organic groups played the key roles in modifying the surface properties. During the oxidation reaction, a phenyl group was found to be better than methyl and propyl groups.

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Effect of CO2 Treatment on the Performance of Sm0.5Sr0.5CoO3-δCathode Electrocatalyst ZHANG Haizhou;CONG You;YANG Weishen* 2008, 29 (1):  7-9.  Abstract ( 2083 )   [Full Text(HTML)] () PDF (251KB) ( 799 )   The Sm0.5Sr0.5CoO3-δ(SSC) cathode was fabricated under slightly overfired condition and was in situ treated with 25%CO2 (V/V) under single cell operating circumstance. XRD and TG analysis demonstrated that some SrCO3 and Co3O4 appeared on the SSC surface after CO2 treatment at 600 ℃. The existence of SrCoO3-δand Co3O4 under air sweep condition resulted in the changes of physicochemical properties of cathode surface to some extent. The acceleration of oxygen reduction rate of the cathode electrocatalyst evidently decreased the polarization resistance and consequently yielded about 20% higher cell performance than the untreated one.

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Cu3/2PMo12O40/SiO2: A Heterogeneous, Eco-friendly and Reusable Catalyst for the Solvent-Free Catalytic Preparation of 1,1-Diacetates from Aldehydes Razieh FAZAELI*;Hamid ALIYAN* 2008, 29 (1):  10-14.  Abstract ( 1983 )   [Full Text(HTML)] () PDF (251KB) ( 864 )   Aromatic and aliphatic aldehydes were transformed to1,1-diacetates (acylals) under mild conditions by treatment with acetic anhydride and Cu3/2PMo12O40/SiO2 catalyst. This catalyst was efficient for the preparation of1,1-diacetate under solvent-free conditions. The reverse reaction using the resulting1,1-diacetate was achieved using the same catalyst in acetonitrile as a solvent. This new method has the advantages of excellent yields and short reaction time. The catalyst can be reused several times although it gets less active.

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Enhancement of Toluene Degradation by Corona Discharge in the Presence of Fenton-Type Reagents KANG Ying;WU Zucheng*;LI Mingbo;WANG Xiaotun 2008, 29 (1):  15-18.  Abstract ( 1895 )   [Full Text(HTML)] () PDF (190KB) ( 785 )   Electro-Fenton reactions were used to enhance the degradation of toluene in gas phase corona discharge by aerosol dispersion. The catalysts can remarkably increase the average degradation rate of toluene. The enhancement factors (β) of toluene degradation rate at gas flux = 0.6 m3/h and initial toluene concentration = 900 mg/m3 were 1.29, 1.28, and 1.51, respectively, using 0.05 mol/L of Fe2+, Co2+, and Mn2+Fenton-type reagents at the applied voltage of 23 kV. These three elements possess similar catalytic activity, with Mn2+showing a slightly better result than Co2+and Fe2+. When the catalyst concentration was0.03-0.1mol/L, the enhancement of toluene degradation rate was more obvious. The degradation products of toluene such as phenyl aldehyde, benzoic acid, and fumaric acid were detected in liquid phase samples collected in the catalyst trap chamber. The increase in toluene degradation rate is due to the dissolution of intermediate products in micro-droplets and the occurrence of electro-Fenton reactions in them. The combination of aerosol dispersion and electro-Fenton reactions may have an important application in air pollution treatment.

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Sol-Gel Preparation and Characterization of Activated Carbon Supported TiO2 Photocatalyst LIU Shouxin*;CHEN Xi 2008, 29 (1):  19-24.  Abstract ( 2239 )   [Full Text(HTML)] () PDF (585KB) ( 1126 )   Activated carbon (AC)-supported TiO2 photocatalysts (TiO2/AC) were prepared by a sol-gel method from Ti(OBu)4. The photocatalysts were characterized byX-raydiffraction, diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopic analysis, and N2 adsorption isotherm. The results indicated that AC could improve the dispersion, decrease the aggregate size, and inhibit the phase transformation of TiO2 from anatase to rutile.Ti-O-Cbonds were formed between the AC bulk and TiO2. AC had no effect on the band-gap structure and crystalline size of TiO2. The photocatalytic activity was investigated by phenol degradation. The results showed that AC could provide high reaction concentration for TiO2. TiO2/AC with a suitable AC content exhibited higher activity than naked TiO2 for low concentration phenol. Synergy coefficients observed for the catalyst with 5%, 9%, and 15% AC were 1.1, 1.5, and 1.3, respectively. Phenol removal of 95.84% was achieved even when the catalyst with 9% AC was recycled seven times.

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Synthesis and Properties of CuO/Zeolite Sandwich \=Type Adsorbent-Catalysts Marius BRAZLAUSKAS*;Saulius KITRYS 2008, 29 (1):  25-30.  Abstract ( 1885 )   [Full Text(HTML)] () PDF (469KB) ( 919 )   The CuO/zeolite sandwich type adsorbent-catalysts were prepared by wet impregnation of parent synthetic zeolites (NaA, CaA, NaX, and CaX) with copper(Ⅱ) nitrate water solution (50.0 g/L) for2 h, followed by drying for1 hand calcination at 450 ℃ for 6 h. Composed coatings of active component (CuO) on parent zeolites are about 1 mm. The parent zeolites, impregnated media, and adsorbent-catalysts were characterized by atomic absorption spectroscopy,X-raydiffraction, infrared spectroscopy, and differential scanning calorimetry. The adsorbent-catalysts were used for catalytic oxidation of alcohol (methanol, 1-propanol, and 1-butanol) vapor, and the catalytic activity tests were carried out in a fixed-bed quartz reactor in the100-350℃ range. The by-products and their concentration in the feed stream of air were determined. The maximum quantities of by-products were formed in the range of220-250℃. The lifetime of the CuO/zeolite catalysts for the oxidation of alcohols was about 4 months. At this time, sandwich-type catalysts were active for the oxidation of alcohols into CO2 and H2O in the range of100-350℃. With increasing molecular weight of alcohols and decreasing their initial concentration in the feed stream, the temperatures of light-off and total oxidation to CO2 and H2O decreased.

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Photocatalytic Degradation of Rhodamine B and Phenol by TiO2 Loaded on Mesoporous Graphitic Carbon XIAO Yi;DANG Liqin;AN Lizhen;BAI Shiying;LEI Zhibin;* 2008, 29 (1):  31-36.  Abstract ( 2262 )   [Full Text(HTML)] () PDF (376KB) ( 1223 )   Mesoporous graphitic carbon with high surface area (298.2 m2/g) was fabricated at 950 ℃ using monodisperse colloid SiO2 with diameter of 26 nm as the template, styrene as the carbon precursor, and Ni as the catalyst. The obtained carbon material was characterized by powderX-raydiffraction, N2 adsorption, thermogravimetric analysis, and transmission electron microscopy. The presence of Ni was crucial to the formation of graphitized mesoporous carbon. The TiO2/graphitic carbon composite was prepared by loading TiO2 in the mesopores of the graphitic carbon via the sol-gel method. Both the surface area and pore volume of the composite were significantly reduced in contrast to the mesoporous graphitic carbon. The photoactivity of TiO2/graphitic carbon was investigated by photocatalytic degradation aqueous solutions of rhodamine B and phenol. The degradation of both rhodamine B and phenol followed first-order reaction kinetics, and the composite showed higher photoactivity than the pure anatase TiO2.

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Assembling Forms of Active Phases Confined within SBA-15 Channels LI Changli;ZHANG Qinghong*;WANG Ye;WAN Huilin* 2008, 29 (1):  37-40.  Abstract ( 2304 )   [Full Text(HTML)] () PDF (328KB) ( 1022 )   The assembling forms of active phases in Pd/SBA-15(ad) and MoO3/SBA-15 catalyst samples, prepared via adsorption-reduction and impregnation-reduction, respectively, were characterized by N2 physisorption measurement. Based on N2 adsorption-desorption isotherms, it was speculated that the palladium species in Pd/SBA-15(ad) exist as nanoparticles, whereas the MoO3 species in MoO3/SBA-15 are layered dispersed on the wall within the SBA-15 channels. These speculations were further confirmed by HR-TEM observation. The SBA-15 confined uniform Pd nanoparticles were efficient for solvent-free aerobic oxidation of benzyl alcohol.

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Biodiesel Production Catalyzed by Whole-Cell Lipase from Rhizopus chinensis HE Qin;XU Yan*;TENG Yun;WANG Dong 2008, 29 (1):  41-46.  Abstract ( 2854 )   [Full Text(HTML)] () PDF (340KB) ( 1437 )   Compared with five commercial lipases, the whole-cell lipase of Rhizopus chinensis CCTCC M201021 (RCL) showed high catalytic ability in the transesterification of soybean oil to fatty acid methyl ester (biodiesel) in the solvent-free system. The effect of reaction parameters including methanol content, water content, lipase amount, and reaction temperature on transesterification was investigated. The biodiesel yield was more than 86.0% in the solvent-free system under the optimal reaction conditions. The effect of different organic solvents on the transesterification indicated that the best one was n-heptane with higher log P values(4.0-4.5). The whole-cell lipase was also proved to be an efficient and potential biocatalyst for biodiesel production from oleic acid and simulant high acid value oil in the solvent-free system.

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Immobilization of Bacillus megaterium Epoxide Hydrolase and Its Catalytic Performance JIA Tao;XU Jianhe*;YANG Sheng 2008, 29 (1):  47-51.  Abstract ( 2151 )   [Full Text(HTML)] () PDF (265KB) ( 982 )   The immobilization of Bacillus megaterium ECU1001 epoxide hydrolase was investigated. Macro-reticular DEAE-cellulose was selected to immobilize the epoxide hydrolase and the activity retention was about 70%. The effect of temperature and pH on the immobilized epoxide hydrolase was measured. Batch reactions of the hydrolysis of rac-glycidyl phenyl ether were conducted with the immobilized epoxide hydrolase at a low substrate concentration. The residual enzyme activity of 72.4% was achieved after 10 cycles of reaction.

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Selective Hydrogenation of Phthalic Anhydride to Phthalide over Supported Nickel Catalysts LIU Yingxin*;WEI Zuojun;FU Jie;GAO Ying;YAN Wei 2008, 29 (1):  52-56.  Abstract ( 2513 )   [Full Text(HTML)] () PDF (294KB) ( 1326 )   The selective hydrogenation of phthalic anhydride to phthalide in liquid phase was studied with nickel catalysts supported on SiO2, TiO2,γ-Al2O3, TiO2-SiO2, and TiO2-Al2O3 carriers prepared by the incipient wetness impregnation method, using nickel nitrate as the nickel precursor. The results showed that the nickel catalyst supported on TiO2-SiO2 with well-dispersed active nickel species exhibited the highest activity and selectivity for phthalide. Then, a series of Ni/TiO2-SiO2 catalysts were prepared by sol-gel method through changing the preparation conditions. The sol-gel Ni/TiO2-SiO2 catalyst using water as the solvent had much better catalytic performance than the one using alcohol as solvent and the one prepared by the impregnation method. Improperly high calcination temperature and reduction temperature caused sintering of nickel species and reduced the catalytic activity. In addition, the nickel precursors obviously affected the performance of the catalysts. The catalyst prepared from nickel chloride showed higher activity and selectivity than the catalysts prepared from nickel sulfate and nickel nitrate. Over this catalyst, the conversion of phthalic anhydride was 100%, and the selectivity for phthalide was 88.5%.

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Immobilization of Lipase on Nano- and Microporous Ceramic Foam HUANG Lei;CHENG Zhenmin* 2008, 29 (1):  57-62.  Abstract ( 2367 )   [Full Text(HTML)] () PDF (243KB) ( 1066 )   The effect of pore size distribution and superficial properties of the ceramic foam was investigated. The nanopore size distribution of the ceramic foam was very suitable to immobilize lipase and had crucial effect on the catalytic efficiency of the immobilized lipase. After 1 h immobilization, the lipase activity per gram carrier on the ceramic foam was 1.33 times that on commercial diatomite, and the volume activity was 2.63 times. The protein loading was 45.36 mg/g, specific activity1215.39U/g, and activity recovery 41.2%. The batch operation stability of the immobilized lipase on the ceramic foam was good in the synthesis of ethyl acetate in an organic phase. The acetic acid conversion in the 5-batch continual operation was maintained at nearly 93% after 3 h reaction in each batch.

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Effect of CO2 on Stability of Cu-Based Catalyst for Dimethyl Ether Synthesis in Slurry Phase WANG Dongsheng;TAN Yisheng*;HAN Yizhuo;Noritatsu TSUBAKI 2008, 29 (1):  63-68.  Abstract ( 2112 )   [Full Text(HTML)] () PDF (317KB) ( 764 )   The effect of CO2 concentration on the stability of the Cu-based catalyst was studied under the reaction conditions of 260 ℃, 5.0 MPa, and4000h-1. High concentration CO2 caused rapid deactivation of the Cu-based catalyst. Temperature-programmed reduction, N2 adsorption, elemental analysis, transmission electron microscopy, andX-rayphotoelectron spectroscopy were used to characterize the reduction behavior, surface physical properties, components, and surface morphologies of the Cu-based catalyst. Under the reaction condition of high CO2 concentration, the catalyst particle size increased and the total pore volume and BET surface area decreased greatly. There was significant metal loss of Zn and Al, and the synergistic effect between Cu and ZnO became weaker under the one-step slurry phase dimethyl ether synthesis conditions. High concentration CO2 restrained carbon deposition to some extent.

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Conversion of Animal Fat over Various Catalysts TIAN Hua;LI Chunyi*;YANG Chaohe;SHAN Honghong 2008, 29 (1):  69-74.  Abstract ( 2139 )   [Full Text(HTML)] () PDF (305KB) ( 1027 )   USY, HZSM-5, ANA, Al2O3, and SiO2 catalysts were used to study the effects of catalysts on the conversion of animal fat and yields of products in a fixed-bed microreactor. The results showed that the initial decomposition (mainly cleavage of theC-Obond) of animal fat proceeded through decarboxylation and decarbonylation reactions. Subsequent cracking of the resulting heavy hydrocarbons and oxygenated hydrocarbons into light molecules (such as liquefied petroleum gas and gasoline) occurred on acid sites of the catalysts. The conversion of this secondary cracking over USY and HZSM-5 zeolites was high because of their strong acid sites. However, the weak acidic Al2O3 catalyst containing large pores permitted a mild secondary cracking with a lower conversion. On the other hand, the secondary cracking was strongly inhibited on non-acidic and large pore SiO2 catalyst and non-acidic and none pore ANA zeolite. The conversion on these two catalysts was much low, and there were a lot of heavy oxygenated hydrocarbons in the liquid products. Additionally, more CO2 was produced by thermal cracking, but a relatively more CO was formed by catalytic cracking.

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A Density Functional Theory Study on Co-adsorption of CO and O on Rh(111) Surface YANG Mingmei;BAO Xinhe;LI Weixue* 2008, 29 (1):  75-80.  Abstract ( 2116 )   [Full Text(HTML)] () PDF (308KB) ( 745 )   CO and O adsorption and co-adsorption on Rh(111) surfaces were studied by density functional theory calculations. Three types of co-adsorption systems, (2×2)-(CO+O), (2×2)-(2CO+O), and (2×2)-(CO+2O), were considered from energy, geometry, work function, and chemical shift points of view. The interactions between CO and O are repulsive, which is explained in terms of bonding competition. The calculated chemical shift of CO and O agrees well with experimental studies, which convince that it is a powerful method to predict the adsorption from theoretical chemical shifts.

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Mechanism of SO2 Influence on NO Removal over V2O5/AC Catalyst XIAO Yong;LIU Zhenyu;*;LIU Qingya;WANG Jiancheng;XING Xinyan;HUANG Zhanggen; 2008, 29 (1):  81-85.  Abstract ( 2302 )   [Full Text(HTML)] () PDF (343KB) ( 791 )   O2 and SO2 transient response experiments were carried out to study the influence of SO2 on NO removal over the V2O5/AC (activated coke) catalyst in the presence of H2O. VOSO4 formed in the reaction of SO2 with V2O5 resulted in the decrease in NO removal activity of the V2O5/AC catalyst. The amount of VOSO4 in the catalyst was affected by both SO2 concentration and the amount of SO2 that was captured. Micropores of the V2O5/AC catalyst were favorable for the migration and deposition of SO3 and therefore benefited the NO removal over the catalyst.

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Facile, Efficient and One-Pot Synthesis of Anthraquinone Derivatives Catalyzed by AlCl3/H2SO4 under Heterogeneous and Mild Conditions Naeimi HOSSEI*;Namdari ROOZBEH 2008, 29 (1):  86-90.  Abstract ( 2149 )   [Full Text(HTML)] () PDF (264KB) ( 774 )   A new method for the preparation of anthraquinone derivatives with a higher yield than those of previously reported methods was achieved. This method has the advantage of starting with readily available materials. In this reaction the products were obtained in high yield with short reaction time and easy operation under mild conditions. The structure of the products was assigned by physical data and spectroscopic methods.

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Preparation of Photocatalysts with Tailored Structures and Their Correlation to the Photocatalytic Efficiency LI Hexing*;ZHU Jian 2008, 29 (1):  91-98.  Abstract ( 2284 )   [Full Text(HTML)] () PDF (700KB) ( 1274 )   The keystone of photocatalysis research is the design of highly efficient photocatalysts. This paper describes the applications of supercritical treatment, alcoholysis, evaporation induced self-assembly, and aerogel drying methods in the preparation of various titania and non-titania photocatalysts with tailored structures. The correlation of the catalytic properties to the structural characteristics is discussed briefly, which shows that theuniquecomposition, structure, and morphology play key roles in enhancing the photocatalytic performance.