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2012, Vol. 21, No. 6　Online: 2012-11-22

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Effect of Ca promoter on LPG synthesis from syngas over hybrid catalyst Xiangang Ma, Qingjie Ge*, Chuanyan Fang, Hengyong Xu* 2012, 21(6): 615-619.  DOI: 10.1016/S1003-9953(11)60415-5 摘要 ( 7289 )   Direct synthesis of liquefied petroleum gas (LPG) from syngas was carried out over hybrid catalyst consisting of methanol synthesis catalyst and modified Y zeolite with Pd and Ca by different methods. The decrease of CO conversion was mostly attributable to the sintering of Cu in methanol synthesis catalyst. On the other hand, coke deposition on Y zeolite was the reason for the decrease of LPG selectivity. The introduction of Ca decreased the strong acid sites of Y zeolite, suppressed coke formation, and thus improved the stability of hybrid catalyst.

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Utilization of compressed natural gas for the production of carbon nanotubes Kim Yang Lee wei ming Dr Chai Siang Piao Abdul Rahman Mohamed 2012, 21(6): 620-624.  DOI: 10.1016/S1003-9953(11)60410-6 摘要 ( 11201 )   The present work aims at utilizing compressed natural gas (CNG) as carbon source for the synthesis of carbon nanotubes (CNTs) over CoO-MoO/Al2O3 catalyst via catalytic chemical vapor deposition (CCVD) method. The as-produced carbonaceous product was characterized by thermal gravimetric analyzer (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. The experimental finding shows that CNTs were successfully produced from CNG while carbon nanofibers (CNFs) were formed as the side products. In addition, the catalytic activity and lifetime were found sustained and prolonged, as compared with using high purity methane as carbon source. The present study suggests an alternative route which can effectively produce CNTs and CNFs using low cost CNG.

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Methane hydrate formation and dissociation in synthetic seawater Vikash Kumar Saw, Iqbal Ahmad, Ajay Mandal*, G. Udayabhanu, Sukumar Laik 2012, 21(6): 625-632.  DOI: 10.1016/S1003-9953(11)60411-8 摘要 ( 8894 )   The formation and dissociation of methane gas hydrate at an interface between synthetic seawater (SSW) and methane gas have been experimentally investigated in the present work. The amount of gas consumed during hydrate formation has been calculated using the real gas equation. Induction time for the formation of hydrate is found to depend on the degree of subcooling. All the experiments were conducted in quiescent system with initial cell pressure of 11.14 MPa. Salinity effects on the onset pressure and temperature of hydrate formation are also observed. The dissociation enthalpies of methane hydrate in synthetic seawater were determined by Clausius-Clapeyron equation based on the measured phase equilibrium data. The dissociation data have been analyzed by existing models and compared with the reported data.

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Simulation and energy performance assessment of CO2 removal from crude synthetic natural gas via physical absorption process Wanjun Guo, Fei Feng, Guohui Song, Jun Xiao, Laihong Shen* 2012, 21(6): 633-638.  DOI: 10.1016/S1003-9953(11)60412-X 摘要 ( 7041 )   The paper presents an energy performance assessment of CO2 removal for crude synthetic natural gas (SNG) upgrade by Selexol absorption process. A simplified process simulation of the Selexol process concerning power requirement and separation performance was developed. The assessment indicates that less pressure difference between crude SNG and absorption pressure favors the energy performance of CO2 removal process. When both crude SNG and absorption pressures are 20 bar, CO2 removal process has the best energy performance. The optimal specific power consumption of the CO2 removal process is 566 kJ/kgCO2. The sensitivity analysis shows that the CO2 removal efficiency would significantly influence the total power consumption of the removal process, as well as higher heating value (HHV) and CO2 content in SNG. However, the specific power consumption excluding crude SNG and SNG compressions changes little with the variance of CO2 removal efficiency. If by-product CO2 is compressed for CO2 capture, the process would turn into a CO2-sink for the atmosphere. Correspondingly, an increase of 281 kJ/kgCO2 in specific power consumption is required for compressing the separated CO2.

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CNTs tuning and vertical alignment in anodic aluminium oxide membrane Maria Sarno*, Diana Sannino, Caterina Leone, Paolo Ciambelli 2012, 21(6): 639-646.  DOI: 10.1016/S1003-9953(11)60413-1 摘要 ( 8018 )   Anodic aluminium oxide (AAOM) membranes were used for template growth of carbon nanotubes (CNT) inside their pores by chemical vapour deposition (CVD) of different hydrocarbons, in the absence of transition metal catalyst. A composite material, containing one nanotube for each channel, having the same length as the membrane thickness and the external diameter close to the diameter of the membrane holes, was obtained. Yield, selectivity, and quality of CNTs in terms of diameter (up to very thin CNT), carbon order, length, arrangement (i.e. number of tubes for each channel), purity, that are critical requisites for several applications were optimised by investigating the effect of changing the hydrocarbon feedstock gas, also in the presence of hydrogen. The samples produced using methane as a feedstock have a well ordered structure. The role of the alumina channels surface during the CNT growth has been investigated and its catalytic activity has been proved for the first time.

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Adsorptive desulfurization over hierarchical beta zeolite by alkaline treatment Fuping Tian*, Xiaojian Yang, Yanchun Shi, Cuiying Jia, Yongying Chen 2012, 21(6): 647-652.  DOI: 10.1016/S1003-9953(11)60414-3 摘要 ( 9075 )   Hierarchical beta zeolites with SiO2/Al2O3 molar ratios of 16 to 25 were obtained by alkaline treatment in NaOH solution. The effects of treatment temperature on crystallinity, textural properties and chemical composites were studied by XRD, N2 sorption, FT-IR and XRF techniques. The desulfurization performance of parent and alkaline-treated beta zeolites was investigated by static absorption in four model fuels, containing four sulfur compounds of different molecular sizes like thiophene (TP), 3-methylthiophene (3-MT), benzothiophene (BT) and dibenzothiophene (DBT), respectively. The crystallinity was observed to be successfully maintained when the treatment temperature was below 50 ℃. Mesoporosity of beta zeolite was evidently developed with alkaline treatment. The formation of mesopore remarkably improved the desulfurization performance for TP, 3-MT, BT and DBT, especially for DBT with larger molecular diameter. Though the addition of toluene in the model fuels resulted in a significant drop of the desulfurization performance of mesoporous beta zeolite, the introduction of cerium ions to some extent mitigated the effect of toluene, which means that both the adsorbent’s porous structure and the adsorption mode are responsible for the desulfurization performance. The adsorbent of cerium ion-exchanged mesoporous beta showed about 80% recovery of desulfurization after the first regeneration.

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Meso-macroporous Al2O3 supported Ru catalysts for CO preferential oxidation in hydrogen-rich gases Limiao Shen, Cheng Zhang, Yuan Liu* 2012, 21(6): 653-660.  DOI: 10.1016/S1003-9953(11)60416-7 摘要 ( 7897 )   Series of meso-macroporous Al2O3 supported Ru catalysts with different loadings were prepared by incipient wetness method and applied to preferential oxidation of CO in hydrogen-rich gases. N2 adsorption-desorption, SEM, XRD, TEM, CO chemisorption and H2-TPR techniques were employed to characterize the catalysts. The results indicate that Ru/Al2O3 catalysts have meso-macroporous structure, high surface area and high metal dispersion. The characterization results of XRD and CO chemisorption indicate the entry of Ru ions into Al2O3 lattice. The results of catalytic performance tests indicate that the meso-macroporous Al2O3 supported Ru catalysts for CO preferential oxidation showed good activity under high space velocity. It is proposed that the macropores in the Ru/Al2O3 catalyst favor mass transfer and mesopores help to improve the dispersion of metal, resulting in the excellent catalytic performance.

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Simultaneous production and utilization of methanol for methyl formate synthesis in a looped heat exchanger reactor configuration A. Goosheneshin1, R. Maleki2, D. Iranshahi2, M. R. Rahimpour2, A. Jahanmiri2* 2012, 21(6): 661-672.  DOI: 10.1016/S1003-9953(11)60417-9 摘要 ( 8350 )   In this investigation, a novel thermally coupled reactor (TCR) containing methyl formate (MF) production in the endothermic side and methanol synthesis in the exothermic side has been investigated. The interesting feature of this TCR is that productive methanol in the exothermic side could be recycled and used as feed of endothermic side for MF synthesis. Other important advantages of the proposed system are high production rates of hydrogen and MF. The configuration consists of two thermally coupled concentric tubular reactors. In these coupled reactors, autothermal system is obtained within the reactor. A steady-state heterogeneous model is used for simulation of the coupled reactor. The proposed model has been utilized to compare the performance of TCR with the conventional methanol reactor (CMR). Noticeable enhancement can be obtained in the performance of the reactors. The influence of operational parameters is studied on reactor performance. The results show that coupling of these reactions could be feasible and beneficial. Experimental proof-of-concept is required to validate the operation of the novel reactor.

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Effects of Ru nanoparticle sizes confined in cavities of SBA-16 on the catalytic performance of Fischer-Tropsch synthesis reaction Jian Chen, Jinlin Li*, Yanxi Zhao, Yuhua Zhang, Jingping Hong 2012, 21(6): 673-679.  DOI: 10.1016/S1003-9953(11)60418-0 摘要 ( 10178 )   Ru nanoparticles with different sizes confined in the cavities of mesoporous SBA-16 have been successfully synthesized by incipient wetness impregnation method with a Ru loading of 4 wt%. The catalysts were characterized by XRD, N2 adsorption-desorption, H2-TPR, H2-TPD, O2-titration and TEM. The catalytic performance of Fischer-Tropsch synthesis over the catalyst was tested in a fixed-bed reactor. The addition of citric acid in the impregnation procedure shows a significant influence on the size of Ru nanoparticles. The selectivity to C5+ increases, while the selectivities to methane and C2-C4 light hydrocarbons decrease with Ru average particles size from 2.0 nm to 9.3 nm, . The Ru catalyst confined in the SBA-16 with average nanoparticle size of 5.3 nm gives the best activity.

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Synthesis of nanoporous copper terephthalate [MIL-53(Cu)] as a novel methane-storage adsorbent Mansoor Anbia*, Sara Sheykhi 2012, 21(6): 680-684.  DOI: 10.1016/S1003-9953(11)60419-2 摘要 ( 8093 )   Copper (II) dicarboxylate, MIL-53, metal-organic framework synthesized hydrothermally has been used for the first time as an adsorbent for methane gas adsorption. Methane adsorption capacity of MIL-53(Cu) was increased to about 8.52 mmol·g-1 at 298 K and 35 bar for methane storage. The adsorbent was characterized by X-ray diffraction (XRD), Brunauer-Emmet-Teller (BET) method, Fourier transform infrared (FT-IR), thermo gravimetric analysis (TGA) and scanning electron microscopy (SEM). The adsorption property of CH4, on MIL-53(Cu) was investigated by volumetric measurement. The enhancement of CH4 adsorption capacity of MIL-53(Cu) is attributed to the increase of micropore volume of MIL-53(Cu).

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A high-surface-area silicoaluminophosphate material rich in Brönsted acid sites as a matrix in catalytic cracking Shaojun Xu, Qiang Zhang, Zhaoxuan Feng, Xiaojing Meng, Tongyu Zhao, Chunyi Li*, 2012, 21(6): 685-693.  DOI: 10.1016/S1003-9953(11)60420-9 摘要 ( 9940 )    A transparent gel-like mesoporous silicoaluminophosphate material (SAP) with molar ratio of Si/Al = 20 was synthesized by hydrothermal method. The physicochemical features of SAP were characterized by XRD, XRF, BET, SEM and FT-IR spectroscopy of pyridine adsorption techniques. The results indicated that incorporation of phosphorus (P) into aluminasilica system altered the basic textural characteristics of aluminasilica. Especially after hydrothermal treatment, the material with large special surface area (up to 492 m2/g) exhibited a good performance on hydrothermal stability. Moreover, the phosphorus modifier can not only increase the amount of Br\"{o}nsted acidic sites (up to 48.44 μmol/g) and the percentage of weak acidic sites in total acidic sites, but also regulate the acid type, such as the ratio of B/L (Lewis acid/Brönsted acid) increased to 1.15. The performances of samples as matrices for the catalytic cracking of heavy VGO were investigated. At 520 ℃, the catalysts showed much higher gasoline and diesel oil yields achieving to 45.59 wt% and 19.20 wt%, respectively, and lower coke selectivity (2.86%) than conventional FCC matrices, such as kaolin and amorphous silica-alumina.

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Thermodynamic analysis of combined reforming process using Gibbs energy minimization method: In view of solid carbon formation Behzad Nematollahi, Mehran Rezaei*, Ebrahim Nemati Lay, Majid Khajenoori 2012, 21(6): 694-702.  DOI: 10.1016/S1003-9953(11)60421-0 摘要 ( 7959 )   Thermodynamic analysis was applied to study combined partial oxidation and carbon dioxide reforming of methane in view of carbon formation. The equilibrium calculations employing the Gibbs energy minimization were performed upon wide ranges of pressure (1-25 atm), temperature (600-1300 K), carbon dioxide to methane ratio (0-2) and oxygen to methane ratio (0-1). The thermodynamic results were compared with the results obtained over a Ru supported catalyst. The results revealed that by increasing the reaction pressure methane conversion decreased. Also it was found that the atmospheric pressure is the preferable pressure for both dry reforming and partial oxidation of methane and increasing the temperature caused increases in both activity of carbon and conversion of methane. The results clearly showed that the addition of O2 to the feed mixture could lead to a reduction of carbon deposition.

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Effect of CeO2 addition on Ni/Al2O3 catalysts for methanation of carbon dioxide with hydrogen Hezhi Liu, Xiujing Zou, Xueguang Wang*, Xionggang Lu, Weizhong Ding 2012, 21(6): 703-707.  DOI: 10.1016/S1003-9953(11)60422-2 摘要 ( 8608 )   The Ni-CeO2/Al2O3 catalysts with a nickel content of 15 wt% prepared via impregnating boehmite were found to be highly active and stable for methanation of carbon dioxide with hydrogen at a H2/CO2 molar ratio of 4. The effects of CeO2 content and reaction temperature on the performance of the Ni-CeO2/Al2O3 catalysts were studied in detail. The results showed that the catalytic performance was strongly dependent on the CeO2 content in Ni-CeO2/Al2O3 catalysts and that the catalysts with 2 wt% CeO2 had the highest catalytic activity among the tested ones at 350 ℃. The XRD and H2-TPR characterizations revealed that the addition of CeO2 decreased the reduction temperature by altering the interaction between Ni and Al2O3, and improved the reducibility of the catalyst. Preliminary stability test of 120 h on stream over the Ni-2CeO2/Al2O3 catalyst at 350 ℃ revealed that the catalyst was much better than the unpromoted one.

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A DFT study of methane activation on graphite surfaces with vacancy defects Fengsi Liu, Wei Chu*, Wenjing Sun, Ying Xue, Qian Jiang 2012, 21(6): 708-712.  DOI: 10.1016/S1003-9953(11)60423-4 摘要 ( 8182 )   The activation of methane on graphite surfaces with monovacancies and 5-8-5 vacancies have been investigated using density functional theory. Sixteen different initial adsorption configurations were investigated to identify the most favorable activation site. It is found that methane tends to be activated on the defective graphite surfaces, and the most stable configuration is that methane activation happened in the center hole of the monovacancy site, with a reaction energy of 1.13 eV. Electron transfer and weaker electrostatic potential of the vacancy region indicate that carbon atom of methane tends to fill the vacancy and makes the system more stable.

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Cobalt supported on CNTs-covered γ- and nano-structured alumina catalysts utilized for wax selective Fischer-Tropsch synthesis Mohammad Reza Hemmati, Mohammad Kazemeini*, Farhad Khorasheh, Jamshid Zarkesh, A 2012, 21(6): 713-721.  DOI: 10.1016/S1003-9953(11)60424-6 摘要 ( 8591 )   Cobalt supported on carbon nanotubes (CNTs)-covered alumina has been recently developed and successfully utilized as a catalyst in Fischer-Tropsch synthesis (FTS). Problems associated with shaping of Co/CNTs into extrudates or pellets as well as catalyst attrition rendered these materials unfavorable for industrial applications. In this investigation regular γ- and nano-structured (N-S) alumina as well as CNTs-covered regular γ- and N-S-alumina supports were impregnated by cobalt nitrate solution to make new cobalt-based catalysts which were also promoted by Ru. The catalysts were characterized and tested in a micro reactor to evaluate their applicability in FTS. γ-Al2O3 was prepared by calcination of bohemite and N-S-Al2O3 was prepared by sol-gel method using aluminum chloride as starting material. Catalyst evaluations indicated that N-S-Al2O3 was superior to regular γ-Al2O3 and that CNTs-covered alumina supports were favored over non-covered ones in terms of activity and heavy hydrocarbon selectivity. These were justified by porosimetric characteristics of the catalysts and existence of CNTs points of view. CNTs-covered catalysts also showed higher wax selectivity and better resistance to deactivation. Furthermore, TPR analysis indicated that the cobalt aluminate phase, which is responsible for the permanent deactivation of alumina supported Co-based catalysts, did not form on alumina supported Co-based catalysts covered with CNTs due to weaker interactions between cobalt and alumina.

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Ruthenium promotion of Co/SBA-15 catalysts for Fischer-Tropsch synthesis in slurry-phase reactors Jocielys Jovelino Rodrigues*, Gina Pecchi, Fabiano Andre Narciso Fernandes 2012, 21(6): 722-728.  DOI: 10.1016/S1003-9953(11)60425-8 摘要 ( 8864 )   The aim of this work was to evaluate the catalytic properties of a Ru promoted Co/SBA-15 catalyst for Fischer-Tropsch synthesis (FTS). The Ru promoted Co/SBA-15 catalyst was prepared by wet impregnation method and was characterized by X-ray diffraction, X-ray energy dispersion spectrophotometer, N2 adsorption-desorption, temperature-programmed reduction and transmission electron microscopy. The Fischer-Tropsch synthesis using the catalyst was carried out to evaluate the catalyst activity and its effect on FTS product distribution. The synthesis was carried out in a slurry reactor operating at 513 K, 20 atm, CO : H2 molar ratio of 1 : 1. X-ray diffraction showed that the calcined cobalt catalyst did not modify the structure of SBA-15, proving that Co was present in the form of Co3O4 in the catalyst. The addition of cobalt in SBA-15 decreased the specific superficial area of the molecular sieve. Fischer-Tropsch synthesis activity and C5+ hydrocarbon selectivity increased with the addition of Ru. The increases in activity and selectivity were attributed to the increased number of active sites resulting from higher reducibility and the synergetic effect of Ru and Co. Ru/Co/SBA-15 catalysts showed moderate conversion (40%) and high selectivity towards the production of C5+ (80 wt%).

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Comparison of the activities of binder-added and binder-free Mo/HZSM-5 catalysts in methane dehydroaromatization at 1073 K in periodic CH4-H2 switch operation mode Yuebing Xu, Hongtao Ma, Yo Yamamoto, Yoshizo Suzuki, Zhanguo Zhang* 2012, 21(6): 729-744.  DOI: 10.1016/S1003-9953(11)60426-X 摘要 ( 8396 )   Three industry-supplied, well-shaped Mo/HZSM-5 catalysts, two binder-added and one binder-free, were tested for the first time in methane dehydroaromatization to benzene at 1073 K and 10000 mL/(g·h) in periodic CH4-H2 switch operation mode, and their catalytic performances were compared with those of three self-prepared, binder-free powder Mo/HZSM-5 catalysts. XRD, 27Al NMR, SEM, BET and NH3-TPD characterizations of all the catalysts show that the zeolites in the two binder-added catalysts are comparable to those in the three binder-free powder catalysts in crystallinity, crystal size, micropore volume and Br{\o}nsted acidity. The test results, on the other hand, show that the catalytic performances of the two binder-added catalysts are worse than those of the four binder-free catalysts on both catalyst mass and zeolite mass bases. Then, TPO and BET measurements of all spent samples were conducted to get a deep insight into the negative effects of binder addition, and the results suggest that the binder additives functioned mainly to enhance the polyaromatization of formed aromatics to coke on their external surfaces and consequently lower the catalysts' benzene formation activity and selectivity.

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Perovskite LaFeO3 supported bi-metal catalyst for syngas methanation Hong Wang, Yuzhen Fang, Yuan Liu*, Xue Bai 2012, 21(6): 745-752.  DOI: 10.1016/S1003-9953(11)60427-1 摘要 ( 8576 )   LaFeO3 perovskite supported Ni and Ni-Fe catalysts were prepared and applied to methanation reaction of syngas. Two preparation methods were employed. One was one-step citrate complexing method, and the other was a two step method using citrate complexing method to produce LaFeO3 and followed by loading nickel oxide on it with impregnation. The structure evolution of the sample as prepared was investigated by XRD, TPR and TEM techniques. For the former, the chemical composites of the calcined sample are NiO-Fe2O3/LaFe1-xNixO3. After reduction and reaction of CO methanation, its composites convert to Fe-Ni@Ni/LaFeO3-La2O2CO3, in which Fe-Ni@Ni is metal particles in nano-size composed of nickel core and Fe-Ni alloy shell. For the latter, the chemical composites of the calcined sample are NiO/LaFeO3; and after reduction and reaction of CO methanation, its chemical composites change to Ni/LaFeO3. Ni/LaFeO3 catalyst is a little more active, while Fe-Ni@Ni/LaFeO3-La2O2CO3 is much more stable and shows very good resistance to carbon deposition. In this work it is aimed to show that the structure and composites of the catalysts can be tailored using perovskite-type oxide as precursor with different preparing method or preparing condition. Therefore, it is a promising route to prepare supported bi-metal catalysts in nano-size for a lot of metals with desired catalytic performances.

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In situ IR study of dimethyl oxalate hydrogenation to ethylene glycol over Cu/SiO2 catalyst Shengguo Hui, Bo Zhang, Suhua Zhang, Wei Li* 2012, 21(6): 753-758.  DOI: 10.1016/S1003-9953(11)60428-3 摘要 ( 10326 )   The mechanism of dimethyl oxalate hydrogenation to ethylene glycol over Cu/SiO2 catalyst was investigated by in situ Fourier transform infrared (FTIR) spectroscopy. It was found that dimethyl oxalate and methyl glycolate proceeded via dissociative adsorption on Cu/SiO2 catalyst, and four main intermediates, CH3OC(O)(O)C-M (1655 cm-1), M-C(O)(O)C-M (1618 cm-1), HOCH2(O)C--M (1682 cm-1) and CH3O-M (2924-2926 cm-1), were identified during the reaction. It was concluded that dimethyl oxalate hydrogenation to ethylene glycol mainly proceeded along the route: dimethyl oxalate \rightarrow CH3OC(O)(O)C-M → methyl glycolate →HOCH2(O)C-M → ethylene glycol. Finally a schematic reaction network was proposed.

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Preparation of mesoporous activated carbons from coal liquefaction residue for methane decomposition Jianbo Zhang, Lijun Jin, Shengwei Zhu, Haoquan Hu* 2012, 21(6): 759-766.  DOI: 10.1016/S1003-9953(11)60429-5 摘要 ( 11483 )   Mesoporous activated carbons were prepared from direct coal liquefaction residue (CLR) by KOH activation method, and the experiments were carried out to investigate the effects of KOH/CLR ratio, solvent for mixing the CLR and KOH, and carbonization procedure on the resultant carbon texture and catalytic activity for catalytic methane decomposition (CMD). The results showed that optimal KOH/CLR ratio of 2 : 1; solvent with higher solubility to KOH or the CLR, and an appropriate carbonization procedure are conductive to improving the carbon pore structure and catalytic activity for CMD. The resultant mesoporous carbons show higher and more stable activity than microporous carbons. Additionally, the relationship between the carbon textural properties and the catalytic activity for CMD was also discussed.

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Effect of composite supports on the methanation activity of Co-Mo-based sulphur-resistant catalysts Haiyang Wang, Zhenhua Li*, Erdong Wang, Can Lin, Yuguang Shang, Guozhong Ding, X 2012, 21(6): 767-773.  DOI: 10.1016/S1003-9953(11)60430-1 摘要 ( 8051 )   The effects of composite supports of CeO2-Al2O3, MgO-Al2O3, TiO2-Al2O3 or ZrO2-Al2O3 on the methanation activity of supported Co-Mo-based sulphur-resistant catalysts were investigated. The catalysts were further characterized by nitrogen adsorption measurement, X-ray diffraction and X-ray photoelectron spectroscopy. The catalyst of 5%CoO-15%MoO3 supported on CeO2-Al2O3, MgO-Al2O3, TiO2-Al2O3 or ZrO2-Al2O3 composite oxides, respectively, showed different catalytic performances of syngas methanation in the presence of hydrogen sulphide as compared with that of the 5%CoO-15%MoO3/Al2O3 catalyst. The Co-Mo/CeO2-Al2O3 catalyst shows the highest methanation activity among the tested catalysts. The enhanced methanation activity may be attributed to the improvement of the dispersion of active metal species and the inhibition of the formation of S6+.

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Research on KOH/La-Ba-Al2O3 catalysts for biodiesel production via transesterification from microalgae oil Xiaoyu Zhang, Qing Ma, Bibo Cheng, Jun Wang, Jinshan Li, Fude Nie* 2012, 21(6): 774-779.  DOI: 10.1016/S1003-9953(11)60431-3 摘要 ( 7973 )   Alumina supports modified by lanthanum (La) and barium (Ba) were prepared by peptization. Catalysts with different KOH contents supported on modified alumina were prepared by impregnation method. Various techniques, including N2 adsorption-desorption (Brunauer-Emmet-Teller method, BET), X-ray diffraction (XRD), scanning electron microscopy (SEM), and fourier transform infrared absorption spectroscopy (FT-IR). Catalytic activity for microalgae oil conversion to methyl ester via transesterification was evaluated and analyzed by GC-MS and GC. BET results showed that the support possessed high specific surface area, suitable pore volume and pore size distribution. Activity results indicated that the catalyst with 25 wt% KOH showed the best activity for microalgae oil conversion. XRD and SEM results revealed that Al-O-K compound was the active phase for microalgae oil conversion. The agglomeration and changing of pore structure should be the main reasons for the catalyst deactivation when KOH content was higher than 30 wt%.