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2014, Vol. 23, No. 1　Online: 2014-01-20


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Prof. Zhao in his article on pages 1–8 reported the production of hydrogen via the electrolysis of ammonia in alkaline electrolytic solution. A new electro-catalyst was designed with the deposition of noble metal on nickel foam substrates. The cell voltage of 0.58 V can be obtained at a current density of 2.5 mA/cm2, which was greatly less than the practical electrolysis voltage of water (1.6 V). The energy consumption for per gram of H2 produced from ammonia electrolysis was only 15.5 Wh.

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Electrolysis of ammonia for hydrogen production catalyzed by Pt and Pt-Ir deposited on nickel foam Min Jiang, Dandan Zhu, Xuebo Zhao 2014, 23(1): 1-8.  DOI: 10.1016/S2095-4956(14)60110-8 摘要 ( 7812 )   Electrolysis of ammonia in alkaline electrolyte solution was applied for the production of hydrogen. Both Pt-loaded Ni foam and Pt-Ir loaded Ni foam electrodes were prepared by electrodeposition and served as anode and cathode in ammonia electrolytic cell, respectively. The electrochemical behaviors of ammonia in KOH solution were individually investigated via cyclic voltammetry on three electrodes, i.e. bare Ni foam electrode, Pt-loaded Ni foam electrode and Pt-Ir loaded Ni foam electrode. The morphology and composition of the prepared Ni foam electrode were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Effects of the concentration of electrolyte solution and temperature of electrolytic cell on the electrolysis reaction were examined in order to enhance the efficiency of ammonia electrolysis. The competition of ammonia electrolysis and water electrolysis in the same alkaline solution was firstly proposed to explain the changes of cell voltage with the electrolysis proceeding. At varying current densities, different cell voltages could be obtained from galvanostatic curves. The low cell voltage of 0.58 V, which is less than the practical electrolysis voltage of water (1.6 V), can be obtained at a current density of 2.5 mA/cm2. Based on some experimental parameters, such as the applied current, the resulting cell voltage and output of hydrogen gas, the power consumption per gram of H2 produced can be estimated.

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Effect of Ti substitution on hydrogen storage properties of Zr1-xTixCo (x = 0, 0.1, 0.2, 0.3) alloys Yamin Zhao, Rongfeng Li, Ruihe Tang, Boyan Li, Ronghai Yu, Wei Liu, Huaqin Kou, Jianbo Meng 2014, 23(1): 9-14.  DOI: 10.1016/S2095-4956(14)60111-X 摘要 ( 7030 )   Zr1-xTixCo (x = 0, 0.1, 0.2, 0.3) alloys were prepared by arc-melting method and the effect of Ti substitution on hydrogen storage properties was studied systematically. Hydrogen desorption pressure-composition-temperature (PCT) measurements were carried out using Sievert's type volumetric apparatus for ZrCo (at 473 K, 573 K and 673 K) and Zr1-xTixCo alloys (at 673 K), respectively. Products after dehydrogenation were characterized by X-ray diffraction (XRD). In addition, the kinetics of Zr1-xTixCo hydride was investigated at 473 K and 673 K, respectively, under hydrogen pressure of 5 MPa. Results showed that Ti substitution for Zr did not change the crystal structure of ZrCo phase. With the increase of temperature from 473 K to 673 K, the extent of disproportionation for ZrCo alloy increased. With Ti content increasing at 673 K, the desorption equilibrium pressure of Zr1-xTixCo-H2 systems elevated and the disproportionation reaction of Zr1-xTixCo alloys was inhibited effectively. Ti substitution decreased the kinetics rate and the effective hydrogen storage capacity of Zr1-xTixCo alloys slightly. Generally speaking, it was found that Zr0.8Ti0.2Co alloy had better anti-disproportionation property with less decrease of effective hydrogen storage capacity which was beneficial to tritium application in the International Thermonuclear Experimental Reactor (ITER).

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Characterization of La-promoted Ni/Al2O3 catalysts for hydrogen production from glycerol dry reforming Kah Weng Siew, Hua Chyn Lee, Jolius Gimbun, Chin Kui Cheng 2014, 23(1): 15-21.  DOI: 10.1016/S2095-4956(14)60112-1 摘要 ( 7430 )   In the current paper, dry (CO2)-reforming of glycerol, a new reforming route, was carried out over alumina (Al2O3)-supported, non-promoted and lanthanum-promoted nickel (Ni) catalysts. Both sets of catalysts were synthesized via a wet co-impregnation procedure. Physicochemical characterization of the catalysts showed that the promoted catalyst possessed smaller metal crystallite size, hence higher metal dispersion compared to the virgin Ni/Al2O3 catalyst. This was also corroborated by the surface images captured by the FESEM analysis. From temperature-programmed calcination analysis, the derivative weight profiles revealed two peaks, which represent a water elimination peak at a temperature range of 373 to 473 K followed by nickel nitrate decomposition from 473 to 573 K. In addition, BET surface area measurements gave 85.0 m2·g-1 for the non-promoted Ni catalyst, whilst the promoted catalysts showed an average of 1% to 6% improvement depending on the La loadings. Significantly, reaction studies at 873 K showed that glycerol dry reforming successfully produced H2. The 2%La-Ni/Al2O3 catalyst, which possessed the largest BET surface area, gave an optimum H2 generation (9.70%) at a glycerol conversion of 24.5%.

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Efficient fixation of CO2 at mild conditions by a Cr-conjugated microporous polymer Yong Xie, Rui-Xia Yang, Nian-Yu Huang, Hua-Jun Luo, Wei-Qiao Deng 2014, 23(1): 22-28.  DOI: 10.1016/S2095-4956(14)60113-3 摘要 ( 8390 )   We reported a bifunctional material, Cr-salen implanted conjugated microporous polymer (Cr-CMP), which is able to capture excellent CO2 amounts and has a remarkable catalytic activity towards the cycloaddition reaction of CO2 to epoxides forming cyclic carbonates at mild conditions without additional solvents. This heterogeneous Cr-CMP catalyst has a superior catalytic activity to its related homogeneous catalyst and can be reused more than ten times without a significant decrease in catalytic activity.

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Comparative study on stability and coke deposition over supported Rh and FePO4 catalysts for oxy-bromination of methane Ronghe Lin, Yunjie Ding, Runqin Wang 2014, 23(1): 29-34.  DOI: 10.1016/S2095-4956(14)60114-5 摘要 ( 7902 )   Rhodium- and iron phosphate-based catalysts are by far the most promising catalysts for oxy-bromination of methane (OBM) reaction. However, most literature reported either Rh- or FePO4-based catalysts, and the results were rarely studied in a uniform environmental condition. In this report, comparative study was conducted on silica- and silicon carbide-supported rhodium and iron phosphate catalysts with the main focuses on stability performance and coke deposition. The catalytic results demonstrated that the stability of both Rh- and FePO4-based catalysts was greatly influenced by the supports used, and silicon carbide-supported catalysts showed much better anti-coking ability as compared with silica-supported ones. Temperature-programmed oxidation over the used catalysts further indicated that the coke formation mechanisms were completely different between silica-supported rhodium and iron phosphate catalysts. While cokes might be caused by condensation of CH2Br2 over supported iron phosphate, methane decomposition might be the reason for coke formation over silica-supported rhodium catalyst. These findings might pave the way for designing highly efficient and stable catalysts of the OBM reaction.

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Effect of cobalt and its adding sequence on the catalytic performance of MoO3/Al2O3 toward sulfur-resistant methanation Baowei Wang, Yuqin Yao, Minhong Jiang, Zhenhua Li, Xinbin Ma, Shaodong Qin, Qi Sun 2014, 23(1): 35-42.  DOI: 10.1016/S2095-4956(14)60115-7 摘要 ( 7116 )   The effect of promoter cobalt and the sequences of adding cobalt and molybdenum precursors on the performance of sulfur-resistant methanation were investigated. All these samples were prepared by impregnation method and characterized by N2-adsorption, X-ray diffraction (XRD), temperature-programmed reduction (TPR) and laser Raman spectroscopy (LRS). The conversions of CO for Mo-Co/Al, Co-Mo/Al and CoMo/Al catalysts were 59.7%, 54.3% and 53.9%, respectively. Among these catalysts, the Mo-Co/Al catalyst prepared stepwisely by impregnating Mo precursor firstly showed the best catalytic performance. Meanwhile, the conversions of CO were 48.9% for Mo/Al catalyst and 10.5% for Co/Al catalyst. The addition of cobalt species could improve the catalytic activity of Mo/Al catalyst. The N2-adsorption results showed that Co-Mo/Al catalyst had the smallest specific surface area among these catalysts. CoMoO4 species in CoMo/Al catalyst were detected with XRD, TPR and LRS. Moreover, crystal MoS2 which was reported to be less active than amorphous MoS2 was found in both Co-Mo/Al and CoMo/Al catalysts. Mo-Co/Al catalyst showed the best catalytic performance as it had an appropriate surface structure, i.e., no crystal MoS2 and very little CoMoO4 species.

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Direct conversion of corn cob to formic and acetic acids over nano oxide catalysts Liyuan Cheng, Hong Liu, Yuming Cui, Nianhua Xue, Weiping Ding 2014, 23(1): 43-49.  DOI: 10.1016/S2095-4956(14)60116-9 摘要 ( 9577 )   Considering energy shortage, large molecules in corn cob and easy separation of solid catalysts, nano oxides are used to transform corn cob into useful chemicals. Because of the microcrystals, nano oxides offer enough accessible sites for cellulose, hemicellulose and monosaccharide from corn cob hydrolysis and oxidant. Chemical conversion of corn cob to organic acids is investigated over nano ceria, alumina, titania and zirconia under various atmospheres. Liquid products are mainly formic and acetic acids. A small amount of other compounds, such as D-xylose, D-glucose, arabinose and xylitol are also detected simultaneously. The yield of organic acids reaches 25%-29% over the nano oxide of ceria, zirconia and alumina with 3 h reaction time under 453 K and 1.2 MPa O2. The unique and fast conversion of corn cob is directly approached over the nano oxides. The results are comparative to those of biofermentation and offer an alternative method in chemically catalytic conversion of corn cob to useful chemicals in a one-pot chemical process.

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Core-shell structured nanospheres with mesoporous silica shell and Ni core as a stable catalyst for hydrolytic dehydrogenation of ammonia borane Hua Liu, Changyan Cao, Ping Li, Yu Yu, Weiguo Song 2014, 23(1): 50-56.  DOI: 10.1016/S2095-4956(14)60117-0 摘要 ( 7382 )   Core-shell structured nanospheres with mesoporous silica shell and Ni core (denoted as Ni@meso-SiO2) are prepared through a three-step process. Monodispersed Ni precursors are first prepared, and then coated with mesoporous SiO2. Final Ni@meso-SiO2 spheres are obtained after calcination. The products are characterized by X-ray powder diffraction, transmission electron microscopy and N2 adsorption-desorption methods. These spheres have a high surface area and are well dispersed in water, showing a high catalytic activity with a TOF value of 18.5, and outstanding stability in hydrolytic dehydrogenation of ammonia borane at room temperature.

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Enhancement of bimetallic Fe-Mn/CNTs nano catalyst activity and product selectivity using microemulsion technique Zahra Zolfaghari, Ahmad Tavasoli, Saber Tabyar, Ali Nakhaei Pour 2014, 23(1): 57-65.  DOI: 10.1016/S2095-4956(14)60118-2 摘要 ( 9864 )   Bimetallic Fe-Mn nano catalysts supported on carbon nanotubes (CNTs) were prepared using microemulsion technique with water-to-surfactant ratios of 0.4-1.6. The nano catalysts were extensively characterized by different methods and their activity and selectivity in Fischer-Tropsch synthesis (FTS) have been assessed in a fixed-bed microreactor. The physicochemical properties and performance of the nanocatalysts were compared with the catalyst prepared by impregnation method. Very narrow particle size distribution has been produced by the microemulsion technique at relatively high loading of active metal. TEM images showed that small metal nano particles in the range of 3-7 nm were not only confined inside the CNTs but also located on the outer surface of the CNTs. Using microemulsion technique with water to surfactant ratio of 0.4 decreased the average iron particle sizes to 5.1 nm. The reduction percentage and dispersion percentage were almost doubled. Activity and selectivity were found to be dependent on the catalyst preparation method and average iron particle size. CO conversion and FTS rate increased from 49.1% to 71.0% and 0.144 to 0.289 gHC/(gcat·h), respectively. While the WGS rate decreased from 0.097 to 0.056 gCO2/(gcat·h). C5+ liquid hydrocarbons selectivity decreased slightly and olefins selectivity almost doubled.

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Nickel catalysts supported on MgO with different specific surface area for carbon dioxide reforming of methane Luming Zhang, Lin Li, Yuhua Zhang, Yanxi Zhao, Jinlin Li 2014, 23(1): 66-72.  DOI: 10.1016/S2095-4956(14)60119-4 摘要 ( 7331 )   In this paper, three kinds of MgO with different specific surface area were prepared, and their effects on the catalytic performance of nickel catalysts for the carbon dioxide reforming of methane were investigated. The results showed that MgO support with the higher specific surface area led to the higher dispersion of the active metal, which resulted in the higher initial activity. On the other hand, the specific surface area of MgO materials might not be the dominant factor for the basicity of support to chemisorb and activate CO2, which was another important factor for the performance of catalysts. Herein, Ni/MgO(CA) catalyst with proper specific surface area and strong ability to activate CO2 exhibited stable catalytic property and the carbon species deposited on the Ni/MgO(CA) catalyst after 10 h of reaction at 650 ℃ were mainly activated carbon species.

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Study on stabilities and electrochemical behavior of V(V) electrolyte with acid additives for vanadium redox flow battery Gang Wang, Jinwei Chen, Xueqin Wang, Jing Tian, Hong Kang, Xuejing Zhu, Yu Zhang, Xiaojiang Liu, Ruilin Wang 2014, 23(1): 73-81.  DOI: 10.1016/S2095-4956(14)60120-0 摘要 ( 7809 )   Several acid compounds have been employed as additives of the V(V) electrolyte for vanadium redox flow battery (VRB) to improve its stability and electrochemical activity. Stability of the V(V) electrolyte with and without additives was investigated with ex-situ heating/cooling treatment at a wide temperature range of -5 ℃ to 60 ℃. It was observed that methanesulfonic acid, boric acid, hydrochloric acid, trifluoroacetic acid, polyacrylic acid, oxalic acid, methacrylic acid and phosphotungstic acid could improve the stability of the V(V) electrolyte at a certain range of temperature. Their electrochemical behaviors in the V(V) electrolyte were further studied by cyclic voltammetry (CV), steady state polarization and electrochemical impedance spectroscopy (EIS). The results showed that the electrochemical activity, including the reversibility of electrode reaction, the diffusivity of V(V) species, the polarization resistance and the flexibility of charge transfer for the V(V) electrolyte with these additives were all improved compared with the pristine solution.

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A dandelion-like carbon microsphere/MnO2 nanosheets composite for supercapacitors Xuanxuan Zhang, Fen Ran, Huili Fan, Yongtao Tan, Lei Zhao,Xiaoming Li, Lingbin Kong, Long Kang 2014, 23(1): 82-90.  DOI: 10.1016/S2095-4956(14)60121-2 摘要 ( 8085 )   This article reported the electrochemical performance of a novel cabon microsphere/MnO2 nanosheets (CMS/MnO2) composite prepared by a in situ self-limiting deposition method under hydrothermal condition. The results of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that MnO2 nanosheets homogeneously grew onto the surface of CMS to form a loose-packed and dandelion-like core/shell microstructure. The unique microstructure plays a basic role in electrochemical accessibility of electrolyte to MnO2 active material and a fast diffusion rate within the redox phase. The results of cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectrometry indicated that the prepared CMS/MnO2 composite presented high capacitance of 181 F·g-1 and long cycle life of 61% capacity retention after 2000 charge/discharge cycles in 1 mol/L Na2SO4 solution, which show strong promise for high-rate electrochemical capacitive energy storage applications.

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Aqueous-phase catalytic hydrogenation of furfural to cyclopentanol over Cu-Mg-Al hydrotalcites derived catalysts：Model reaction for upgrading of bio-oil Minghao Zhou, Zuo Zeng, Hongyan Zhu, Guomin Xiao, Rui Xiao 2014, 23(1): 91-96.  DOI: 10.1016/S2095-4956(14)60109-1 摘要 ( 8220 )   A series of Cu-Mg-Al hydrotalcites derived oxides with a (Cu+Mg)/Al mole ratio of 3 and varied Cu/Mg mole ratio (from 0.07 to 0.30) were prepared by co-precipitation and calcination methods, then they were introduced to the hydrogenation of furfural in aqueous-phase. Effects of Cu/Mg mole ratio, reaction temperature, initial hydrogen pressure, reaction time and catalyst amount on the conversion rate of furfural as well as the selectivity toward desired product cyclopentanol were systematically investigated. The conversion of furfural over calcined hydrotalcite catalyst with a Cu/Mg mole ratio of 0.2 was up to 98.5% when the reaction was carried out under 140 ℃ and the initial hydrogen pressure of 4 MPa for 10 h, while the selectivity toward cyclopentanol was up to 94.8%. The catalysts were characterized by XRD and SEM. XRD diffraction of all the samples showed characteristic pattern of hydrotalcite with varied peak intensity as a result of different Cu content. The catalytic activity was improved gradually with the increase of Cu component in the hydrotalcite.

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Catalytic performance of acidic ionic liquid-functionalized silica in biodiesel production Bin Zhen, Qingze Jiao, Qin Wu, Hansheng Li 2014, 23(1): 97-104.  DOI: 10.1016/S2095-4956(14)60122-4 摘要 ( 7206 )   Acidic ionic liquid ([BsAIm][OTf]) was immobilized on sulfhydryl-group-modified SiO2 (MPS-SiO2) via free radical addition reaction. The [BsAIm][OTf] loading on acidic ionic liquid-functionalized silica ([BsAIm][OTf]/SiO2) was controlled through tuning the sulfydryl (SH) content of MPS-SiO2. All the samples were characterized by FT-IR, elemental analysis, N2 adsorption-desorption measurements and TG-DTA. The catalytic performance of [BsAIm][OTf]/SiO2 in the esterification of oleic acid and the transesterification of glycerol trioleate for biodiesel production was investigated. The results showed that with the increase of [BsAIm][OTf] loading on SiO2 the specific surface area and pore volume of [BsAIm][OTf]/SiO2 decreased, and the pore diameter of [BsAIm][OTf]/SiO2 narrowed. In the esterificaiton of oleic acid, the oleic acid conversion increased with the increasing [BsAIm][OTf] loading. In the transesterification of glycerol trioleate, with the increasing [BsAIm][OTf] loading the glycerol trioleate conversion decreased and the selectivities to glycerol monooleate and methyl oleate increased.

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Carbon matrix/SiNWs heterogeneous block as improved reversible anodes material for lithium ion batteries Yao Wang, Long Ren, Yundan Liu, Xuejun Liu, Kai Huang, Xiaolin Wei, Jun Li, Xiang Qi, Jianxin Zhong 2014, 23(1): 105-110.  DOI: 10.1016/S2095-4956(14)60123-6 摘要 ( 7129 )   A novel carbon matrix/silicon nanowires (SiNWs) heterogeneous block was successfully produced by dispersing SiNWs into templated carbon matrix via a modified evaporation induced self-assembly method. The heterogeneous block was determined by X-ray diffraction, Raman spectra and scanning electron microscopy. As an anode material for lithium batteries, the block was investigated by cyclic voltammograms (CV), charge/discharge tests, galvanostatic cycling performance and A. C. impedance spectroscopy. We show that the SiNWs disperse into the framework, and are nicely wrapped by the carbon matrix. The heterogeneous block exhibits superior electrochemical reversibility with a high specific capacity of 529.3 mAh/g in comparison with bare SiNWs anode with merely about 52.6 mAh/g capacity retention. The block presents excellent cycle stability and capacity retention which can be attributed to the improvement of conductivity by the existence of carbon matrix and the enhancement of ability to relieve the large volume expansion of SiNWs during the lithium insertion/extraction cycle. The results indicate that the as-prepared carbon matrix/SiNWs heterogeneous block can be an attractive and potential anode material for lithium-ion battery applications.

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Amine-functionalized low-cost industrial grade multi-walled carbon nanotubes for the capture of carbon dioxide Qing Liu, Yao Shi, Shudong Zheng, Liqi Ning, Qing Ye, Mengna Tao, Yi He 2014, 23(1): 111-118.  DOI: 10.1016/S2095-4956(14)60124-8 摘要 ( 7616 )   Industrial grade multi-walled carbon nanotubes (IG-MWCNTs) are a low-cost substitute for commercially purified multi-walled carbon nanotubes (P-MWCNTs). In this work, IG-MWCNTs were functionalized with tetraethylenepentamine (TEPA) for CO2 capture. The TEPA impregnated IG-MWCNTs were characterized with various experimental methods including N2 adsorption/desorption isotherms, elemental analysis, X-ray diffraction, Fourier transform infrared spectroscopy and thermogravimetric analysis. Both the adsorption isotherms of IG-MWCNTs-n and the isosteric heats of different adsorption capacities were obtained from experiments. TEPA impregnated IG-MWCNTs were also shown to have high CO2 adsorption capacity comparable to that of TEPA impregnated P-MWCNTs. The adsorption capacity of IG-MWCNTs based adsorbents was in the range of 2.145 to 3.088 mmol/g, depending on adsorption temperatures. Having the advantages of low-cost and high adsorption capacity, TEPA impregnated IG-MWCNTs seem to be a promising adsorbent for CO2 capture from flue gas.

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Numerical study on soot removal in partial oxidation of methane to syngas reactors Weisheng Wei, Tao Zhang, Jian Xu, Wei Du 2014, 23(1): 119-130.  DOI: 10.1016/S2095-4956(14)60125-X 摘要 ( 7485 )   The serious carbon deposition existing in catalytic partial oxidation of methane (CPOM) to syngas process is one of the key problems that impede its industrialization. In this study, 3-dimensional unsteady numerical simulations of the soot formation and oxidation in oxidation section in a heat coupling reactor were carried out by computational fluid dynamics (CFD) approach incorporating the Moss-Brookes model for soot formation. The model has been validated and proven to be in good agreement with experiment results. Effects of nozzle type, nozzle convergence angle, channel spacing, number of channels, radius/height ratio, oxygen/carbon ratio, preheat temperature and additional introduction of steam on the soot formation were simulated. Results show that the soot formation in oxidation section of the heat coupling reactor depends on both nozzle structures and operation conditions, and the soot concentration can be greatly reduced by optimization with the maximum mass fraction of soot inside the oxidation reactor from 2.28% to 0.0501%, and so that the soot mass fraction at the exit reduces from 0.74% to 0.03%.