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2015, Vol. 21, No. 4　Online: 2015-07-15


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Prof. Xiao and coworkers reported an effective NiCo/CNT catalyst for catalytic conversion of guaiacol. The catalysts exhibited very good performance of guaiacol converion with higher selectivity towards desired alcohol with high H/Ceff factor. This work provided a promising alternatives for the catalytic upgrading of bio-oil and its model compounds.

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Mass production of LiFePO4/C energy materials using Fe-P waste slag Gen Li, Pengcheng Wu, Chunhui Luo, Qian Cui, Guixin Wang, Kangping Yan 2015, 21(4): 375-380.  摘要 ( 0 )   To effectively solve the agglomeration problems in the solid state reaction process, pre-adding glucose is adopted to the synthesis of LiFePO4/C energy materials using Fe-P waste slag. The average particle & grain size of LiFePO4/C decreases, and the impurities in LiFePO4/C composites reduce to a great extent. It makes great sense to the mass industrial production. The optimum synthesis conditions determined in this work are based on the orthogonal experiments. The samples synthesized in a scale of 500 g exhibit high purity, excellent electrochemical performance, high reaction activity, good reversibility, and low polarization level. The discharge capacities are 145, 134, 117, and 102 mAh/g at the current densities of 0.1 C, 0.2 C, 0.5 C and 1 C, respectively. This work puts forward a practical suggestion for mass producing environmental benign and low cost LiFePO4/C as cathode materials of lithium ion batteries.

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Mass production of LiFePO4/C energy materials using Fe-P waste slag Gen Li, Pengcheng Wu, Chunhui Luo, Qian Cui, Guixin Wang, Kangping Yan 2015, 24(4): 375-380.  DOI: 10.1016/j.jechem.2015.07.007 摘要 ( 5339 )   To effectively solve the agglomeration problems in the solid state reaction process, pre-adding glucose is adopted to the synthesis of LiFePO4/C energy materials using Fe-P waste slag. The average particle & grain size of LiFePO4/C decreases, and the impurities in LiFePO4/C composites reduce to a great extent. It makes great sense to the mass industrial production. The optimum synthesis conditions determined in this work are based on the orthogonal experiments. The samples synthesized in a scale of 500 g exhibit high purity, excellent electrochemical performance, high reaction activity, good reversibility, and low polarization level. The discharge capacities are 145, 134, 117, and 102 mAh/g at the current densities of 0.1 C, 0.2 C, 0.5 C and 1 C, respectively. This work puts forward a practical suggestion for mass producing environmental benign and low cost LiFePO4/C as cathode materials of lithium ion batteries.

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Transformation of alkali and alkaline-earth metals during coal oxy-fuel combustion in the presence of SO2 and H2O Liying Wang, Haixin Mao, Zengshuang Wang, Jian-Ying Lin, Meijun Wang, Liping Chang 2015, 21(4): 381-387.  摘要 ( 0 )   The occurrence modes of alkali and alkaline-earthmetals (AAEMs) in coal relate to their release behavior and ash formation during combustion. To better understand the transformation of AAEMs, the release behavior of water-soluble, HCl-soluble, HCl-insoluble AAEMs during Shenmu coal (SM coal) oxy-fuel combustion in the presence of SO2 and H2O in a drop-tube reactor was investigated through serial dissolution using H2O and HCl solutions. The results show that the release rates of AAEMs increase with an increase in temperature under the three atmospheres studied. The high release rates of Mg and Ca from SM coal are dependent on the high content of soluble Mg and Ca in SM coal. SO2 inhibits the release rates of AAEMs, while H2O promotes them. The effects of SO2 and H2O on the Na and K species are more evident than those on Mg and Ca species. All three types of AAEMs in coal can volatilize in the gas phase during coal combustion. The W-type AAEMs release excessively, whereas the release rates of I-type AAEMs are relatively lower. Different types of AAEMmay interconvert through different pathways under certain conditions. Both SO2 and H2O promote the transformation reactions. The effect of SO2 was related to sulfate formation and the promotion by H2O occurs because of a decrease in the melting point of the solid as well as the reaction of H2O.

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Transformation of alkali and alkaline-earth metals during coal oxy-fuel combustion in the presence of SO2 and H2O Liying Wang, Haixin Mao, Zengshuang Wang, Jian-Ying Lin, Meijun Wang, Liping Chang 2015, 24(4): 381-387.  DOI: 10.1016/j.jechem.2015.07.006 摘要 ( 8898 )   The occurrence modes of alkali and alkaline-earthmetals (AAEMs) in coal relate to their release behavior and ash formation during combustion. To better understand the transformation of AAEMs, the release behavior of water-soluble, HCl-soluble, HCl-insoluble AAEMs during Shenmu coal (SM coal) oxy-fuel combustion in the presence of SO2 and H2O in a drop-tube reactor was investigated through serial dissolution using H2O and HCl solutions. The results show that the release rates of AAEMs increase with an increase in temperature under the three atmospheres studied. The high release rates of Mg and Ca from SM coal are dependent on the high content of soluble Mg and Ca in SM coal. SO2 inhibits the release rates of AAEMs, while H2O promotes them. The effects of SO2 and H2O on the Na and K species are more evident than those on Mg and Ca species. All three types of AAEMs in coal can volatilize in the gas phase during coal combustion. The W-type AAEMs release excessively, whereas the release rates of I-type AAEMs are relatively lower. Different types of AAEMmay interconvert through different pathways under certain conditions. Both SO2 and H2O promote the transformation reactions. The effect of SO2 was related to sulfate formation and the promotion by H2O occurs because of a decrease in the melting point of the solid as well as the reaction of H2O.

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Preparation of nano-PANI@MnO2 by surface initiated polymerization method using as a nano-tubular electrode material: The amount effect of aniline on the microstructure and electrochemical performance Fen Ran, Yunlong Yang, Lei Zhao, Xiaoqin Niu, Dingjun Zhang, Lingbin Kong, Yongchun Luo, Long Kang 2015, 21(4): 388-393.  摘要 ( 1 )   In this study, nano-polyanline and manganese oxide nanometer tubular composites (nano-PANI@MnO2) were prepared by a surface initiated polymerization method and used as electrochemical capacitor electrode materials; and the effect of aniline amount on the microstructure and electrochemical performance was investigated. The microstructures and surface morphologies of nano-PANI@MnO2 were characterized by X-ray diffraction, scanning electron microscopy and fourier transformation infrared spectroscope. The electrochemical performance of these composite materials was performed with cyclic voltammetry, charge-discharge test and electrochemical impedance spectroscopy, respectively. The results demonstrate that the feed ratio of aniline to MnO2 played a very important role in constructing the hierarchically nano-structure, which would, hence, determine the electrochemical performance of the materials. Using the templateassisted strategy and controlling the feed ratio of aniline to MnO2, the nanometer tubular structure of nano-PANI@MnO2 was obtained. A maximum specific capacitance of 386 F/g was achieved in aqueous 1 mol/L NaNO3 electrolyte with the potential range from 0 to 0.6 V (vs. SCE).

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Preparation of nano-PANI@MnO2 by surface initiated polymerization method using as a nano-tubular electrode material: The amount effect of aniline on the microstructure and electrochemical performance Fen Ran, Yunlong Yang, Lei Zhao, Xiaoqin Niu, Dingjun Zhang, Lingbin Kong, Yongchun Luo, Long Kang 2015, 24(4): 388-393.  DOI: 10.1016/j.jechem.2015.07.003 摘要 ( 5268 )   In this study, nano-polyanline and manganese oxide nanometer tubular composites (nano-PANI@MnO2) were prepared by a surface initiated polymerization method and used as electrochemical capacitor electrode materials; and the effect of aniline amount on the microstructure and electrochemical performance was investigated. The microstructures and surface morphologies of nano-PANI@MnO2 were characterized by X-ray diffraction, scanning electron microscopy and fourier transformation infrared spectroscope. The electrochemical performance of these composite materials was performed with cyclic voltammetry, charge-discharge test and electrochemical impedance spectroscopy, respectively. The results demonstrate that the feed ratio of aniline to MnO2 played a very important role in constructing the hierarchically nano-structure, which would, hence, determine the electrochemical performance of the materials. Using the templateassisted strategy and controlling the feed ratio of aniline to MnO2, the nanometer tubular structure of nano-PANI@MnO2 was obtained. A maximum specific capacitance of 386 F/g was achieved in aqueous 1 mol/L NaNO3 electrolyte with the potential range from 0 to 0.6 V (vs. SCE).

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Effect of CO2 on the structural variation of Na2WO4/Mn/SiO2 catalyst for oxidative coupling of methane to ethylene Jia Shi, Lu Yao, Changwei Hu 2015, 21(4): 394-400.  摘要 ( 0 )   In this work, the influence of CO2 on the structural variation and catalytic performance of Na2WO4/Mn/SiO2 for oxidative coupling of methane to ethylene was investigated. The catalyst was prepared by impregnation method and characterized by XRD, Raman and XPS techniques. Appropriate amount of CO2 in the reactant gases enhanced the formation of surface tetrahedral Na2WO4 species and promoted the migration of O in MOx, Na,Wfrom the catalyst bulk to surface, which were favorable for oxidative coupling of methane. When the molar ratio of CH4/O2/CO2 was 3/1/2, enriched surface tetrahedral Na2WO4 species and high surface concentration of O in MOx, Na, W were detected, and then high CH4 conversion of 33.1% and high C2H4 selectivity of 56.2% were obtained. With further increase of CO2 in the reagent gases, the content of active surface tetrahedral Na2WO4 species and surface concentration of O in MOx, Na, W decreased, while that of inactive species (MnWO4 and Mn2O3) increased dramatically, leading to low CH4 conversion and low C2H4 selectivity. It could be speculated that Na2WO4 crystal was transformed into MnWO4 crystal with excessive CO2 added under the reaction conditions. Pretreatment of Na2WO4/Mn/SiO2 catalyst by moderate amount of CO2 before OCM also promoted the formation of Na2WO4 species.

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Effect of CO2 on the structural variation of Na2WO4/Mn/SiO2 catalyst for oxidative coupling of methane to ethylene Jia Shi, Lu Yao, Changwei Hu 2015, 24(4): 394-400.  DOI: 10.1016/j.jechem.2015.06.007 摘要 ( 9033 )   In this work, the influence of CO2 on the structural variation and catalytic performance of Na2WO4/Mn/SiO2 for oxidative coupling of methane to ethylene was investigated. The catalyst was prepared by impregnation method and characterized by XRD, Raman and XPS techniques. Appropriate amount of CO2 in the reactant gases enhanced the formation of surface tetrahedral Na2WO4 species and promoted the migration of O in MOx, Na,Wfrom the catalyst bulk to surface, which were favorable for oxidative coupling of methane. When the molar ratio of CH4/O2/CO2 was 3/1/2, enriched surface tetrahedral Na2WO4 species and high surface concentration of O in MOx, Na, W were detected, and then high CH4 conversion of 33.1% and high C2H4 selectivity of 56.2% were obtained. With further increase of CO2 in the reagent gases, the content of active surface tetrahedral Na2WO4 species and surface concentration of O in MOx, Na, W decreased, while that of inactive species (MnWO4 and Mn2O3) increased dramatically, leading to low CH4 conversion and low C2H4 selectivity. It could be speculated that Na2WO4 crystal was transformed into MnWO4 crystal with excessive CO2 added under the reaction conditions. Pretreatment of Na2WO4/Mn/SiO2 catalyst by moderate amount of CO2 before OCM also promoted the formation of Na2WO4 species.

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Synthesis of SAPO-34 using metakaolin in the presence of β-cyclodextrin Chen Zhang, Xuchen Lu, Tizhuang Wang 2015, 21(4): 401-406.  摘要 ( 0 )   SAPO-34 molecular sieves were synthesized by the addition of β-cyclodextrin (β-CD) as crystal growth inhibitor using metakaolin as silicon and aluminum sources. Properties of the obtained samples were characterized by XRD, SEM, N2 adsorption-desorption, FTIR, XRF, EDX, NH3-TPD and 29Si MAS NMR. When β-CD was added, crystal size of the SAPO-34 crystals decreased. Variation of Si content from the crystal center to surface decreased while total Si content hardly changed. 29Si MAS NMR results showed that β-CD contributed to better Si dispersion and decreased the size of Si(4Si) patches. Moreover, the MTO (methanol-to-olefin) process was conducted to investigate the influence of β-CD on catalytic performance. The synthesized sample with molar ratio of β-CD/Al2O3 equaling 0.055 remained active for 610 min while the sample synthesized without β-CD for only 280 min, which indicates that the lifetime of catalyst synthesized with β-CD is greatly prolonged.

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Synthesis of SAPO-34 using metakaolin in the presence of β-cyclodextrin Chen Zhang, Xuchen Lu, Tizhuang Wang 2015, 24(4): 401-406.  DOI: 10.1016/j.jechem.2015.06.008 摘要 ( 7197 )   SAPO-34 molecular sieves were synthesized by the addition of β-cyclodextrin (β-CD) as crystal growth inhibitor using metakaolin as silicon and aluminum sources. Properties of the obtained samples were characterized by XRD, SEM, N2 adsorption-desorption, FTIR, XRF, EDX, NH3-TPD and 29Si MAS NMR. When β-CD was added, crystal size of the SAPO-34 crystals decreased. Variation of Si content from the crystal center to surface decreased while total Si content hardly changed. 29Si MAS NMR results showed that β-CD contributed to better Si dispersion and decreased the size of Si(4Si) patches. Moreover, the MTO (methanol-to-olefin) process was conducted to investigate the influence of β-CD on catalytic performance. The synthesized sample with molar ratio of β-CD/Al2O3 equaling 0.055 remained active for 610 min while the sample synthesized without β-CD for only 280 min, which indicates that the lifetime of catalyst synthesized with β-CD is greatly prolonged.

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A reevaluation of the correlation between the synthesis parameters and structure and properties of nitrogen-doped carbon nanotubes Kunpeng Xie, Fengkai Yang, Petra Ebbinghaus, Andreas Erbe, Martin Muhler, Wei Xia 2015, 21(4): 407-415.  摘要 ( 0 )   Nitrogen-doped carbon nanotubes (NCNTs) were synthesized by chemical vapor deposition using cobaltbased oxides as catalyst and ethylenediamine (EDA) as carbon/nitrogen precursor. The influence of growth time, EDA concentration and growth temperature on the morphology, yield, composition, graphitization and oxidation resistance of the NCNTs was systematically investigated by using Raman spectroscopy, temperature-programmed oxidation and other techniques. The NCNT growth from ethylenediamine with a high N/C ratio involves several processes including mainly (1) catalytic growth of NCNTs, (2) homogeneous gas-phase decomposition of EDA, (3) non-catalytic deposition of pyrolytic carbon/nitrogen species and (4) surface etching of amorphous carbon or carbon at defect sites through gasification. At a later growth stage the etching process appears to be dominating, leading to the thinning of nanotubes and the decrease of yield. Moreover, the surface etching through carbon gasification strongly influences the structure and degree of graphitization of NCNTs.

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A reevaluation of the correlation between the synthesis parameters and structure and properties of nitrogen-doped carbon nanotubes Kunpeng Xie, Fengkai Yang, Petra Ebbinghaus, Andreas Erbe, Martin Muhler, Wei Xia 2015, 24(4): 407-415.  DOI: 10.1016/j.jechem.2015.06.016 摘要 ( 6141 )   Nitrogen-doped carbon nanotubes (NCNTs) were synthesized by chemical vapor deposition using cobaltbased oxides as catalyst and ethylenediamine (EDA) as carbon/nitrogen precursor. The influence of growth time, EDA concentration and growth temperature on the morphology, yield, composition, graphitization and oxidation resistance of the NCNTs was systematically investigated by using Raman spectroscopy, temperature-programmed oxidation and other techniques. The NCNT growth from ethylenediamine with a high N/C ratio involves several processes including mainly (1) catalytic growth of NCNTs, (2) homogeneous gas-phase decomposition of EDA, (3) non-catalytic deposition of pyrolytic carbon/nitrogen species and (4) surface etching of amorphous carbon or carbon at defect sites through gasification. At a later growth stage the etching process appears to be dominating, leading to the thinning of nanotubes and the decrease of yield. Moreover, the surface etching through carbon gasification strongly influences the structure and degree of graphitization of NCNTs.

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Methane dry reforming on Ni/La2Zr2O7 treated by plasma in different atmospheres Honggen Peng, Youhe Ma, Wenming Liu, Xianglan Xu, Xiuzhong Fang, Jie Lian, Xiang Wang, Changqing Li, Wufeng Zhou, Ping Yuan 2015, 21(4): 416-424.  摘要 ( 0 )   A series of Ni/La2Zr2O7 pyrochlore catalysts prepared by impregnation method and treated by dielectric barrier discharge (DBD) plasma in different atmospheres and varied sequences were prepared and applied for dry reforming of methane (DRM). It is found that all of the plasma treated catalysts show evidently improved activity and coke resistance in comparison with the non-plasma treated one. The best performance is achieved on Ni/La2Zr2O7-H2P-C, a catalyst treated in H2 plasma before calcination. TGA-DSC and SEM demonstrate that carbon deposition is significantly suppressed on all of the plasma treated samples. Moreover, XRD and TEM results testify that both NiO and Ni sizes on the calcined and reduced samples treated by plasma are also decreased, which results in higher Nimetal dispersion on the reduced and used catalysts and enhances the interactions between Ni sites and the support. It is believed that these are the inherent reasons accounting for the promotional effects of plasma treatment on the reaction performance of the Ni/La2Zr2O7 pyrochlore catalysts.

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Methane dry reforming on Ni/La2Zr2O7 treated by plasma in different atmospheres Honggen Peng, Youhe Ma, Wenming Liu, Xianglan Xu, Xiuzhong Fang, Jie Lian, Xiang Wang, Changqing Li, Wufeng Zhou, Ping Yuan 2015, 24(4): 416-424.  DOI: 10.1016/j.jechem.2015.06.015 摘要 ( 5580 )   A series of Ni/La2Zr2O7 pyrochlore catalysts prepared by impregnation method and treated by dielectric barrier discharge (DBD) plasma in different atmospheres and varied sequences were prepared and applied for dry reforming of methane (DRM). It is found that all of the plasma treated catalysts show evidently improved activity and coke resistance in comparison with the non-plasma treated one. The best performance is achieved on Ni/La2Zr2O7-H2P-C, a catalyst treated in H2 plasma before calcination. TGA-DSC and SEM demonstrate that carbon deposition is significantly suppressed on all of the plasma treated samples. Moreover, XRD and TEM results testify that both NiO and Ni sizes on the calcined and reduced samples treated by plasma are also decreased, which results in higher Nimetal dispersion on the reduced and used catalysts and enhances the interactions between Ni sites and the support. It is believed that these are the inherent reasons accounting for the promotional effects of plasma treatment on the reaction performance of the Ni/La2Zr2O7 pyrochlore catalysts.

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Catalytic conversion of guaiacol to alcohols for bio-oil upgrading Minghao Zhou, Yuan Wang, Yanbin Wang, Guomin Xiao 2015, 21(4): 425-431.  摘要 ( 0 )   Guaiacol was chosen to represent O-containing chemicals with lower effective hydrogen carbon ratio (H/Ceff factor) in bio-oil, and the hydrodeoxygenation of guaiacol was investigated over non-precious and nonsulfided catalysts. Effects of metal composition, reaction temperature, and hydrogen pressure on conversion and selectivity were investigated systematically. Among various compositions of catalysts, NiCo/CNT exhibited best performance of guaiacol conversion with higher selectivity towards desired alcohols with higher H/Ceff factor. The reaction pathways of guaiacol in aqueous were proposed based on the product analyzed. Results show that metal composition and temperature have great effects on the conversion of guaiacol and the yields of desired products.

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Catalytic conversion of guaiacol to alcohols for bio-oil upgrading Minghao Zhou, Yuan Wang, Yanbin Wang, Guomin Xiao 2015, 24(4): 425-431.  DOI: 10.1016/j.jechem.2015.06.012 摘要 ( 9223 )   Guaiacol was chosen to represent O-containing chemicals with lower effective hydrogen carbon ratio (H/Ceff factor) in bio-oil, and the hydrodeoxygenation of guaiacol was investigated over non-precious and nonsulfided catalysts. Effects of metal composition, reaction temperature, and hydrogen pressure on conversion and selectivity were investigated systematically. Among various compositions of catalysts, NiCo/CNT exhibited best performance of guaiacol conversion with higher selectivity towards desired alcohols with higher H/Ceff factor. The reaction pathways of guaiacol in aqueous were proposed based on the product analyzed. Results show that metal composition and temperature have great effects on the conversion of guaiacol and the yields of desired products.

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The tuning of pore structures and acidity for Zn/Al layered double hydroxides: The application on selective hydrodesulfurization for FCC gasoline Tinghai Wang, Jingfeng Li, Yi Su, Chenchen Wang, Yuan Gao, Lingjun Chou, Wenjun Yao 2015, 21(4): 432-440.  摘要 ( 0 )   Co-Mo catalysts applied on the hydrodesulfurization (HDS) for FCC gasoline were prepared with Zn-Al layered double hydroxides (LDHs) to improve their performances, and the effects of pore structures and acidity on HDS performances were studied in detail. A series of Zn-Al/LDHs samples with different pore structures and acidities are synthesized on the bases of co-precipitation of OH-, CO2-, Al3+, and Zn2+. The neutralization pH is a main factor to affect the pore structures and acidity of Zn-Al/LDHs, and a series of Zn-Al/LDHs with different pore structures and acidities are obtained. Based on the representative samples with different specific surface areas (SBET) and acidities, three CoMo/LDHs catalysts were prepared, and their HDS performances were compared with traditional CoMo/Al2O3 catalysts. The results indicated that catalysts prepared with high SBET possessed high HDS activity, and Brönsted acid sites could reduce the thiol content in the product to some extent. All the three catalysts prepared with LDHs displayed little lower HDS activity but higher selectivity than CoMo/Al2O3, and could restrain the reactions of re-combination between olefin and H2S which could be due to the existence of Brönsted acid sites.

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The tuning of pore structures and acidity for Zn/Al layered double hydroxides: The application on selective hydrodesulfurization for FCC gasoline Tinghai Wang, Jingfeng Li, Yi Su, Chenchen Wang, Yuan Gao, Lingjun Chou, Wenjun Yao 2015, 24(4): 432-440.  DOI: 10.1016/j.jechem.2015.06.013 摘要 ( 5305 )   Co-Mo catalysts applied on the hydrodesulfurization (HDS) for FCC gasoline were prepared with Zn-Al layered double hydroxides (LDHs) to improve their performances, and the effects of pore structures and acidity on HDS performances were studied in detail. A series of Zn-Al/LDHs samples with different pore structures and acidities are synthesized on the bases of co-precipitation of OH-, CO2-, Al3+, and Zn2+. The neutralization pH is a main factor to affect the pore structures and acidity of Zn-Al/LDHs, and a series of Zn-Al/LDHs with different pore structures and acidities are obtained. Based on the representative samples with different specific surface areas (SBET) and acidities, three CoMo/LDHs catalysts were prepared, and their HDS performances were compared with traditional CoMo/Al2O3 catalysts. The results indicated that catalysts prepared with high SBET possessed high HDS activity, and Brönsted acid sites could reduce the thiol content in the product to some extent. All the three catalysts prepared with LDHs displayed little lower HDS activity but higher selectivity than CoMo/Al2O3, and could restrain the reactions of re-combination between olefin and H2S which could be due to the existence of Brönsted acid sites.

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Effect of loading on the Ni2P/Al2O3 catalysts for the hydrotreating reactions Junen Wang, Shaozhong Li, Jun Xu, Hui Chen, Jiangyu Yuan, Jianyi Shen 2015, 24(4): 441-447.  DOI: 10.1016/j.jechem.2015.06.014 摘要 ( 1 )   The 80%Ni2P/Al2O3 catalysts were prepared by the phosphidation of corresponding 80%Ni/Al2O3 with triphenylphosphine in liquid phase and compared with the 60%Ni2P/Al2O3 for hydrotreating reactions. Both the 60%Ni2P/Al2O3 and 80%Ni2P/Al2O3 in comparison exhibited the small and uniform Ni2P particles (6.3 and 8.4 nm, respectively), high CO uptakes (305 and 345 μmol/g, respectively) and thus high activities for the hydrotreating reactions. After the hydrotreating reactions, the small and uniform Ni2P particles were remained, although the CO uptakes on the used 60%Ni2P/Al2O3 and 80%Ni2P/Al2O3 were greatly decreased (to 68 and 95 μmol/g, respectively) due to the incorporation of S into the Ni2P surfaces. The 80%Ni2P/Al2O3 was found to be significantly more active than the 60%Ni2P/Al2O3 due to that the 80%Ni2P/Al2O3 possessed more, and more active Ni2P sites than the 60%Ni2P/Al2O3, probably due to the less S incorporated in the 80%Ni2P/Al2O3 than in the 60%Ni2P/Al2O3 during the hydrotreating reactions.

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Effect of loading on the Ni2P/Al2O3 catalysts for the hydrotreating reactions Junen Wang, Shaozhong Li, Jun Xu, Hui Chen, Jiangyu Yuan, Jianyi Shen 2015, 21(4): 441-447.  摘要 ( 0 )   The 80%Ni2P/Al2O3 catalysts were prepared by the phosphidation of corresponding 80%Ni/Al2O3 with triphenylphosphine in liquid phase and compared with the 60%Ni2P/Al2O3 for hydrotreating reactions. Both the 60%Ni2P/Al2O3 and 80%Ni2P/Al2O3 in comparison exhibited the small and uniform Ni2P particles (6.3 and 8.4 nm, respectively), high CO uptakes (305 and 345 μmol/g, respectively) and thus high activities for the hydrotreating reactions. After the hydrotreating reactions, the small and uniform Ni2P particles were remained, although the CO uptakes on the used 60%Ni2P/Al2O3 and 80%Ni2P/Al2O3 were greatly decreased (to 68 and 95 μmol/g, respectively) due to the incorporation of S into the Ni2P surfaces. The 80%Ni2P/Al2O3 was found to be significantly more active than the 60%Ni2P/Al2O3 due to that the 80%Ni2P/Al2O3 possessed more, and more active Ni2P sites than the 60%Ni2P/Al2O3, probably due to the less S incorporated in the 80%Ni2P/Al2O3 than in the 60%Ni2P/Al2O3 during the hydrotreating reactions.

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Core@shell sulfur@polypyrrole nanoparticles sandwiched in graphene sheets as cathode for lithium-sulfur batteries Xiangyang Zhou, Feng Chen, Juan Yang 2015, 24(4): 448-455.  DOI: 10.1016/j.jechem.2015.06.011 摘要 ( 6414 )   A nano sulfur-based composite cathode material featured by uniform core@shell-structured sulfur@ polypyrrole nanoparticles sandwiched in three-dimensional graphene sheets conductive network (S@PPy/GS) is fabricated via a facile solution-based method. The S@PPy nanoparticles are synthesized by in situ chemical oxidative polymerization of pyrrole on the surface of sulfur particles, and then graphene sheets are covered outside the S@PPy nanoparticles, forming a three-dimensional conductive network. When evaluating the electrochemical performance of S@PPy/GS in a lithium-sulfur battery, it delivers large discharge capacity, excellent cycle stability, and good rate capability. The initial discharge capacity is up to 1040 mAh/g at 0.1 C, the capacity can remain 537.8 mAh/g at 0.2 C after 200 cycles, even at a higher rate of 1 C, the specific capacity still reaches 566.5 mAh/g. The good electrochemical performance is attributed to the unique structure of S@PPy/GS, which can not only provide an excellent transport of lithium and electron ions within the electrodes, but also retard the shuttle effect of soluble lithium polysulfides effectively, thus plays a positive role in building better lithium-sulfur batteries.

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Kinetic and thermodynamic studies of the esterification of acidified oil catalyzed by sulfonated cation exchange resin Lingling Ma, Ying Han, Kaian Sun, Jie Lu, Jincheng Ding 2015, 21(4): 456-462.  摘要 ( 0 )   This study describes the kinetics and thermodynamics of the esterification of acidified oil with methanol catalyzed by sulfonated cation exchange resins (SCER). The effects of the mass ratio of methanol to acidified oil, reaction temperature, and catalyst loading were studied to optimize the conditions for maximum conversion of free fatty acids (FFAs). The results showed that the optimal conversion rate of FFAs was 91.87% at the mass ratio of methanol to acidified oil of 2.5:1.0, reaction temperature of 65.0 ℃, catalyst loading of 5.0 g and reaction time of 8.0 h. The external and internal mass transfer resistances were negligible based on the experimental results and a pseudo-homogeneous kinetic model was proposed for the esterification. The activation energy and thermodynamic parameters including ΔG, ΔS and ΔH were determined. The conversion rates of FFAs obtained from the established model were in good agreement with the experimental data.

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Kinetic and thermodynamic studies of the esterification of acidified oil catalyzed by sulfonated cation exchange resin Lingling Ma, Ying Han, Kaian Sun, Jie Lu, Jincheng Ding 2015, 24(4): 456-462.  DOI: 10.1016/j.jechem.2015.07.001 摘要 ( 5203 )   This study describes the kinetics and thermodynamics of the esterification of acidified oil with methanol catalyzed by sulfonated cation exchange resins (SCER). The effects of the mass ratio of methanol to acidified oil, reaction temperature, and catalyst loading were studied to optimize the conditions for maximum conversion of free fatty acids (FFAs). The results showed that the optimal conversion rate of FFAs was 91.87% at the mass ratio of methanol to acidified oil of 2.5:1.0, reaction temperature of 65.0 ℃, catalyst loading of 5.0 g and reaction time of 8.0 h. The external and internal mass transfer resistances were negligible based on the experimental results and a pseudo-homogeneous kinetic model was proposed for the esterification. The activation energy and thermodynamic parameters including ΔG, ΔS and ΔH were determined. The conversion rates of FFAs obtained from the established model were in good agreement with the experimental data.

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Efficient production of biodiesel from both esterification and transesterification over supported SO42--MoO3-ZrO2-Nd2O3/SiO2 catalysts Xiuqin Li, Dongmei Tong, Changwei Hu 2015, 21(4): 463-471.  摘要 ( 1 )   SO42--MoO3-ZrO2-Nd2O3/SiO2 (SMZN/SiO2) catalysts for the production of biodiesel via both esterification and transesterification were prepared and characterized by N2 adsorption-desorption isotherms, X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry analysis (TGA), ammonia adsorption Fourier transform infrared spectra (NH3-FTIR), and ammonia adsorption temperature programmed desorption (NH3-TPD) to reveal the dependence of the stable catalytic activity on calcination time. The reason for catalyst deactivation was also studied. The calcination time remarkably affected the types of active centers on SMZN/SiO2, and 4 h was found to be the optimal calcination time. SO42- species bonded with small size ZrO2 were found to be the stable active centers, where the leaching of SO42- and the deposition of coke were inhibited. The deposition of coke was easier on large size ZrO2 than on small size ones. Calcination in air flow could eliminate the deposited coke to recover the deactivated catalysts.

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Efficient production of biodiesel from both esterification and transesterification over supported SO42--MoO3-ZrO2-Nd2O3/SiO2 catalysts Xiuqin Li, Dongmei Tong, Changwei Hu 2015, 24(4): 463-471.  DOI: 10.1016/j.jechem.2015.06.010 摘要 ( 4527 )   SO42--MoO3-ZrO2-Nd2O3/SiO2 (SMZN/SiO2) catalysts for the production of biodiesel via both esterification and transesterification were prepared and characterized by N2 adsorption-desorption isotherms, X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry analysis (TGA), ammonia adsorption Fourier transform infrared spectra (NH3-FTIR), and ammonia adsorption temperature programmed desorption (NH3-TPD) to reveal the dependence of the stable catalytic activity on calcination time. The reason for catalyst deactivation was also studied. The calcination time remarkably affected the types of active centers on SMZN/SiO2, and 4 h was found to be the optimal calcination time. SO42- species bonded with small size ZrO2 were found to be the stable active centers, where the leaching of SO42- and the deposition of coke were inhibited. The deposition of coke was easier on large size ZrO2 than on small size ones. Calcination in air flow could eliminate the deposited coke to recover the deactivated catalysts.

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Synthesis of silica/metatitanic acid nanocomposite and evaluation of its catalytic performance for aquathermolysis reaction of extra-heavy crude oil Xueliang Liu, Yiguang Li, Zhijun Zhang, Xiaohong Li, Mengyun Zhao, Changming Su 2015, 21(4): 472-476.  摘要 ( 2 )   A lipophilic silica/metatitantic acid (denoted as SiO2/H2TiO3) nanocomposite was synthesized by hydrothermal reaction with surface-modified SiO2 as the lipophilic carrier. As-synthesized SiO2/H2TiO3 nanocomposite was used as a catalyst to promote the aquathermolysis reaction of extra-heavy crude oil thereby facilitating the recovering from the deep reservoirs at lowered temperature. The catalytic performance of the as-synthesized SiO2/H2TiO3 catalyst for the aquathermolysis reaction of the heavy oil at a moderate temperature of 150 ℃ was evaluated in relation to the structural characterizations by TEM, FTIR, XRD and FESEM as well as the determination of the specific surface area by N2 adsorption-desorption method. Findings indicate that as-synthesized SiO2/H2TiO3 nanocomposite exhibits an average size of about 20 nm as well as good lipophilicity and dispersibility in various organic solvents; and it shows good catalytic performance for the aquathermolysis reaction of the extra-heavy oil extracted from Shengli Oilfield of China. Namely, the assynthesized SiO2/H2TiO3 catalyst is capable of significantly reducing the viscosity of the tested heavy oil from 58,000 cP to 16,000 cP (referring to a viscosity reduction rate of 72.41%) at a mass fraction of 0.5%, a reaction temperature of 150 ℃ and a reaction time of 36 h, showing potential application in downhole upgrading heavy crude oils.

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Synthesis of silica/metatitanic acid nanocomposite and evaluation of its catalytic performance for aquathermolysis reaction of extra-heavy crude oil Xueliang Liu, Yiguang Li, Zhijun Zhang, Xiaohong Li, Mengyun Zhao, Changming Su 2015, 24(4): 472-476.  DOI: 10.1016/j.jechem.2015.06.005 摘要 ( 4665 )   A lipophilic silica/metatitantic acid (denoted as SiO2/H2TiO3) nanocomposite was synthesized by hydrothermal reaction with surface-modified SiO2 as the lipophilic carrier. As-synthesized SiO2/H2TiO3 nanocomposite was used as a catalyst to promote the aquathermolysis reaction of extra-heavy crude oil thereby facilitating the recovering from the deep reservoirs at lowered temperature. The catalytic performance of the as-synthesized SiO2/H2TiO3 catalyst for the aquathermolysis reaction of the heavy oil at a moderate temperature of 150 ℃ was evaluated in relation to the structural characterizations by TEM, FTIR, XRD and FESEM as well as the determination of the specific surface area by N2 adsorption-desorption method. Findings indicate that as-synthesized SiO2/H2TiO3 nanocomposite exhibits an average size of about 20 nm as well as good lipophilicity and dispersibility in various organic solvents; and it shows good catalytic performance for the aquathermolysis reaction of the extra-heavy oil extracted from Shengli Oilfield of China. Namely, the assynthesized SiO2/H2TiO3 catalyst is capable of significantly reducing the viscosity of the tested heavy oil from 58,000 cP to 16,000 cP (referring to a viscosity reduction rate of 72.41%) at a mass fraction of 0.5%, a reaction temperature of 150 ℃ and a reaction time of 36 h, showing potential application in downhole upgrading heavy crude oils.

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Performance evaluation of LPG desulfurization by adsorption for hydrogen production S. Al-Zuhair, A. Khalil, M. Hassan, A. Abdulrazak, K. Basel, A. Fardoun 2015, 21(4): 477-484.  摘要 ( 4 )   The adsorption of sulfur compounds, in commercially available LPG, has been studied using different adsorbents, namely Zeolite, ZnO and house made date pits activated carbon (DP-AC). It was found that the three adsorbents are capable of effectively removing sulfur compounds at different feed sulfur concentrations. The effects of height to diameter aspect ratio of the adsorption column, flow rate of LPG and input sulfur concentrations have been studied. A first order kinetics model has been used to describe the adsorption, and the kinetics constant was found to increase by increasing the flow rate of LPG and decrease by increasing the amount of adsorbent used. The developed model described the system fairly well, and can be used in designing and scaling-up of fixed-bed adsorption columns.

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Performance evaluation of LPG desulfurization by adsorption for hydrogen production S. Al-Zuhair, A. Khalil, M. Hassan, A. Abdulrazak, K. Basel, A. Fardoun 2015, 24(4): 477-484.  DOI: 10.1016/j.jechem.2015.06.001 摘要 ( 5 )   The adsorption of sulfur compounds, in commercially available LPG, has been studied using different adsorbents, namely Zeolite, ZnO and house made date pits activated carbon (DP-AC). It was found that the three adsorbents are capable of effectively removing sulfur compounds at different feed sulfur concentrations. The effects of height to diameter aspect ratio of the adsorption column, flow rate of LPG and input sulfur concentrations have been studied. A first order kinetics model has been used to describe the adsorption, and the kinetics constant was found to increase by increasing the flow rate of LPG and decrease by increasing the amount of adsorbent used. The developed model described the system fairly well, and can be used in designing and scaling-up of fixed-bed adsorption columns.

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Understanding of the activity difference between nanogold and bulk gold by relativistic effects Keju Sun, Masanori Kohyama, Shingo Tanaka, Seiji Takeda 2015, 21(4): 485-489.  摘要 ( 2 )   It is a challenge to thoroughly understand the astonishing difference in catalytic activity between nanogold and bulk gold for some oxidation reactions. In this work, the Au-O interactions in various surroundings were investigated by DFT calculations and compared with the Ag-O interactions. We have found the three points. First, only Au-O bond can be significantly strengthened by the linear O-Au-O structure. Second, the Au-O bond is always stronger than the Ag-O bond when the bonds are embedded in common surroundings. Third, the Au-O bond becomes weaker than the Ag-O bond when the number of neighboring Au atoms becomes large, because the Au-O interactions are suppressed by the presence of neighboring gold atoms. The origin of these three points can be attributed to wider spatial extension of d orbitals of gold, induced by strong relativistic effects. The strong relativistic effects make nanogold with smaller coordinate numbers highly active due to the ease in forming strong Au-O bonds, especially for the O-Au-O bond, whereas gold atoms in bulk with larger coordination numbers chemically inert due to the strong suppression by neighboring gold atoms destabilizing the O-Au-O bond.

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Understanding of the activity difference between nanogold and bulk gold by relativistic effects Keju Sun, Masanori Kohyama, Shingo Tanaka, Seiji Takeda 2015, 24(4): 485-489.  DOI: 10.1016/j.jechem.2015.06.006 摘要 ( 5355 )   It is a challenge to thoroughly understand the astonishing difference in catalytic activity between nanogold and bulk gold for some oxidation reactions. In this work, the Au-O interactions in various surroundings were investigated by DFT calculations and compared with the Ag-O interactions. We have found the three points. First, only Au-O bond can be significantly strengthened by the linear O-Au-O structure. Second, the Au-O bond is always stronger than the Ag-O bond when the bonds are embedded in common surroundings. Third, the Au-O bond becomes weaker than the Ag-O bond when the number of neighboring Au atoms becomes large, because the Au-O interactions are suppressed by the presence of neighboring gold atoms. The origin of these three points can be attributed to wider spatial extension of d orbitals of gold, induced by strong relativistic effects. The strong relativistic effects make nanogold with smaller coordinate numbers highly active due to the ease in forming strong Au-O bonds, especially for the O-Au-O bond, whereas gold atoms in bulk with larger coordination numbers chemically inert due to the strong suppression by neighboring gold atoms destabilizing the O-Au-O bond.

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Production of gasoline range hydrocarbons from methanol on hierarchical ZSM-5 and Zn/ZSM-5 catalyst prepared with soft second template Xiaodong Wang, Xiaoxia Gao, Mei Dong, Hongbin Zhao, Wei Huang 2015, 21(4): 490-496.  摘要 ( 1 )   Nano hierarchical mesoporous ZSM-5 catalystswere prepared with cationic dimethyldiallyl ammonium chloride acrylamide copolymer (PDDA) as a soft second template. Using ZSM-5 catalyst as a matrix, Zn/ZSM-5 catalysts were also obtained by the wet impregnation method. The effect of the PDDA amount and Zn loadings on the properties of the catalysts, including crystallinity, morphology, textural properties, acid nature and catalytic activity in MTG reaction, was investigated by XRD, FESEM, TEM, Nitrogen adsorption-desorption isotherms and NH3-TPD method, respectively. The MTG reaction was performed in a fixed bed reactor, and the result revealed that the nano hierarchical ZSM-5 catalyst prepared with a PDDA/Si molar ratio of 0.070 possesses longer stable phase of 70 h with a liquid hydrocarbon selectivity of 29.8%. Zn/ZSM-5 catalyst with a Zn/ZSM-5 ratio of 0.07 wt.% shows the highest liquid hydrocarbon selectivity, reaching 62.5%.

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Production of gasoline range hydrocarbons from methanol on hierarchical ZSM-5 and Zn/ZSM-5 catalyst prepared with soft second template Xiaodong Wang, Xiaoxia Gao, Mei Dong, Hongbin Zhao, Wei Huang 2015, 24(4): 490-496.  DOI: 10.1016/j.jechem.2015.06.009 摘要 ( 4807 )   Nano hierarchical mesoporous ZSM-5 catalystswere prepared with cationic dimethyldiallyl ammonium chloride acrylamide copolymer (PDDA) as a soft second template. Using ZSM-5 catalyst as a matrix, Zn/ZSM-5 catalysts were also obtained by the wet impregnation method. The effect of the PDDA amount and Zn loadings on the properties of the catalysts, including crystallinity, morphology, textural properties, acid nature and catalytic activity in MTG reaction, was investigated by XRD, FESEM, TEM, Nitrogen adsorption-desorption isotherms and NH3-TPD method, respectively. The MTG reaction was performed in a fixed bed reactor, and the result revealed that the nano hierarchical ZSM-5 catalyst prepared with a PDDA/Si molar ratio of 0.070 possesses longer stable phase of 70 h with a liquid hydrocarbon selectivity of 29.8%. Zn/ZSM-5 catalyst with a Zn/ZSM-5 ratio of 0.07 wt.% shows the highest liquid hydrocarbon selectivity, reaching 62.5%.

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SnO2/corncob-derived activated carbon nanohybrid as an anode material for lithium-ion batteries Xiangyang Zhou, Zhen Geng, Cunman Zhang, Jue Wang, Dabin Wang 2015, 21(4): 529-533.  摘要 ( 1 )   A facile synthesis of SnO2/corncob-derived activated carbon (CAC) composite was proposed, and the CAC used here has high specific surface area (over 3000 m2/g) and ample oxygen-containing functional groups. The microstructures and morphology as well as electrochemical performance of the SnO2/CAC composites were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and relevant electrochemical characterization. The results show that the mass ratios of SnO2 to CAC have a significant effect on the structures and properties of the composites. The sample with 34% SnO2 delivered a capacity of 879.8 mAh/g in the first reversible cycle and maintained at 634.0 mAh/g (72.1% retention of the initial reversible capacity) after 100 cycles at a current density of 200 mA/g. After 60 cycles at different specific currents from 200 to 2000 mA/g, the reversible specific capacity was still maintained at 632.8 mAh/g at a current density of 200 mA/g. These results indicate that SnO2/CAC can be a desirable alternative anode material for lithium ion batteries.

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Plastic supported platinum modified nickel electrode and its high electrocatalytic activity for sodium borohydride electrooxidation Bin Wang, Dongming Zhang, Ke Ye, Kui Cheng, Dianxue Cao, Guiling Wang, Xiaoli Cheng 2015, 24(4): 497-502.  DOI: 10.1016/j.jechem.2015.06.002 摘要 ( 4878 )   A novel plastic/multi-walled carbon nanotube (MWNTs)-nickel (Ni)-platinum (Pt) electrode (PMNP) is prepared by chemical-reducing Pt onto the surface of Ni film covered plastic/MWNTs (PM) substrate. TheMWNTs are adhered by a piece of commercial double faced adhesive tape on the surface of plastic paper and the Ni film is prepared by a simple electrodeposition method. The morphology and phase structure of the PMNP electrode are characterized by scanning electron microscopy, transmission electron microscope and X-ray diffractometer. The catalytic activity of the PMNP electrode for NaBH4 electrooxidation is investigated by means of cyclic voltammetry and chronoamperometry. The catalyst combines tightly with the plastic paper and exhibits a good stability. MWNTs serve as both conductive material and hydrogen storage material and the Ni film and Pt are employed as electrochemical catalysts. The PMNP electrode exhibits a high electrocatalytic performance and the oxidation current density reaches to 10.76 A/(mg cm-2) in 0.1mol/dm3 NaBH4 at 0 V,which is much higher than those in the previous reports. The using ofwaste plastic reduces the discarding of white pollution and consumption of metal resources.

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Reactive adsorption desulfurization coupling aromatization on Ni/ZnO-Zn6Al2O9 prepared by ZnxAly(OH)2(CO3)z·xH2O precursor for FCC gasoline Tinghai Wang, Xueli Wang, Yuan Gao, Yi Su, Zhichao Miao, Chenchen Wang, Longgang Lu, Lingjun Chou, Xionghou Gao 2015, 24(4): 503-511.  DOI: 10.1016/j.jechem.2015.07.002 摘要 ( 5035 )   Aiming to improve the reactive adsorption desulfurization (RADS) performances of Ni/ZnO adsorbents, ZnxAly(OH)2(CO3)z·xH2O precursor is synthesized by coprecipitation of Zn2+, AlO2-, and CO32-; the ZnOZn6Al2O9 composite oxides are obtained by the calcination of ZnxAly(OH)2(CO3)z·xH2O precursor, and the Ni/ZnO-Zn6Al2O9 (6.0 wt% NiO) adsorbents are prepared by wetness impregnation method. The phase, acid strength, acid type and quantity, morphology, and thermal propertieswere characterized by X-ray diffraction, temperature-programmed desorption of ammonia, pyridine-adsorbed infrared spectrum, high-resolution transmission electron microscopy, and Thermo Gravimetry-Derivative Thermo Gravimetry (TG-DTG), respectively. The breakthrough sulfur capacities of six adsorbents are between 34.2 and 47.9 mg/gcat. The kinetic studies indicated that the active energy of RADS (49.4 kJ/mol) could reach nano-sized ZnO, the particle size of is about 12.0 nm. All the excellent RADS performances can be due to the high SBET. Also, there are some extents of aromatization reactions that occur, which can be contributed to the Bönsted acid rooted in Zn6Al2O9 composite oxide, and the octane number of products can be preserved well.

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Nanoscale pore morphology and distribution of lacustrine shale reservoirs: Examples from the Upper Triassic Yanchang Formation, Ordos Basin Yang Wang, Yanming Zhu, Hongyan Wang, Guangjun Feng 2015, 24(4): 512-519.  DOI: 10.1016/j.jechem.2015.06.004 摘要 ( 5209 )   Pore structure plays an important role in the gas storage and flow capacity of shale gas reservoirs. Fieldemission environmental scanning electron microscopy (FE-SEM) in combination with low-pressure carbon dioxide gas adsorption (CO2GA), nitrogen gas adsorption (N2GA), and high-pressure mercury intrusion (HPMI) were used to study the nanostructure pore morphology and pore-size distributions (PSDs) of lacustrine shale from the Upper Triassic Yanchang Formation, Ordos Basin. Results show that the pores in the shale reservoirs are generally nanoscale and can be classified into four types: organic, interparticle, intraparticle, and microfracture. The interparticle pores between clay particles and organic-matter pores develop most often, l with pore sizes that vary from several to more than 100 nm. Mercury porosimetry analysis shows total porosities ranging between 1.93 and 7.68%, with a mean value of 5.27%. The BET surface areas as determined by N2 adsorption in the nine samples range from 10 to 20 m2/g and the CO2 equivalent surface areas (< 2 nm) vary from 18 to 71 m2/g. Together, the HPMI, N2GA, and CO2GA curves indicate that the pore volumes are mainly due to pores < 100 nm in size. In contrast, however, most of the specific surface areas are provided by the micropores. The total organic carbon (TOC) and clay minerals are the primary controls of the structures of nanoscale pores (especially micropores and mesopores). Micropores are predominantly determined by the content of the TOC, and mesopores are possibly related to the content of clay minerals, particularly the illite-montmorillonite mixed-layer content.

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Effect of support modification on the characterization and catalytic activity of Mo/Al2O3 catalysts M. Riad, S. Mikhail 2015, 24(4): 520-528.  DOI: 10.1016/j.jechem.2015.06.003 摘要 ( 4928 )   Molybdenum catalysts (15 wt% MoO3 loading) supported on alumina, alumina-magnesia, and alumina-chromia were prepared via impregnation technique and studied for the reaction of methyl-cyclohexane dehydrogenation. The catalystswere evaluated bymeans of FT-IR, XRD, DSC, TPR, and N2 adsorption-desorption isotherms. The results clarified that Mo/alumina-magnesia catalyst possesses small crystallite size and high surface area (240 m2/g) and is selective toward the formation of dehydrogenated product (96.5%). The yield to ring-opening products is higher on Mo/alumina-chromia catalyst due to its higher acidity and larger metal crystals, which favor the ring-opening reaction and lowermetallic activitywith selectivity toward ringopening products (32%).

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SnO2/corncob-derived activated carbon nanohybrid as an anode material for lithium-ion batteries Xiangyang Zhou, Zhen Geng, Cunman Zhang, Jue Wang, Dabin Wang 2015, 24(4): 529-533.  DOI: 10.1016/j.jechem.2015.07.008 摘要 ( 5000 )   A facile synthesis of SnO2/corncob-derived activated carbon (CAC) composite was proposed, and the CAC used here has high specific surface area (over 3000 m2/g) and ample oxygen-containing functional groups. The microstructures and morphology as well as electrochemical performance of the SnO2/CAC composites were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and relevant electrochemical characterization. The results show that the mass ratios of SnO2 to CAC have a significant effect on the structures and properties of the composites. The sample with 34% SnO2 delivered a capacity of 879.8 mAh/g in the first reversible cycle and maintained at 634.0 mAh/g (72.1% retention of the initial reversible capacity) after 100 cycles at a current density of 200 mA/g. After 60 cycles at different specific currents from 200 to 2000 mA/g, the reversible specific capacity was still maintained at 632.8 mAh/g at a current density of 200 mA/g. These results indicate that SnO2/CAC can be a desirable alternative anode material for lithium ion batteries.