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不同包碳方法对泡沫镍@C/Co_3O_4复合材料形貌和超级电容性能影响
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作者 邓亚锋 原勇强 +1 位作者 崔艳华 刘效疆 《化工新型材料》 CAS CSCD 北大核心 2015年第2期191-192,196,共3页
采用CVD沉积、浸渍碳源-高温退火、一步水热和两步水热4种方法制备泡沫镍@C/Co3O4复合材料,对比了4种方法制备材料的结构形貌和电化学性能。结果表明:一步水热法可制备泡沫镍@C/Co3O4材料,较其他方法简洁有效,所得样品电化学性能最好,... 采用CVD沉积、浸渍碳源-高温退火、一步水热和两步水热4种方法制备泡沫镍@C/Co3O4复合材料,对比了4种方法制备材料的结构形貌和电化学性能。结果表明:一步水热法可制备泡沫镍@C/Co3O4材料,较其他方法简洁有效,所得样品电化学性能最好,面积比容量可达1300F/cm2。 展开更多
关键词 包覆方法 碳/氧化钴 超级电容器
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Theoretical studies of CO oxidation with lattice oxygen on Co_3O_4 surfaces 被引量:2
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作者 王阳刚 杨小峰 李隽 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2016年第1期193-198,共6页
Low-temperature CO oxidation has attracted extensive interest in heterogeneous catalysis because of the potential applications in fuel cells,air cleaning,and automotive emission reduction.In the present study,theoreti... Low-temperature CO oxidation has attracted extensive interest in heterogeneous catalysis because of the potential applications in fuel cells,air cleaning,and automotive emission reduction.In the present study,theoretical investigations have been performed using density functional theory to elucidate the crystal plane effect and structure sensitivity of Co3O4 nano-catalysts toward catalyzing CO oxidation.It is shown that the surface Co–O ion pairs are the active site for CO oxidation on the Co3O4 surface.Because of stronger CO adsorption and easier removal of lattice oxygen ions,the Co3O4(011)surface is shown to be more reactive for CO oxidation than the Co3O4(001)surface,which is consistent with previous experimental results.By comparing the reaction pathways at different sites on each surface,we have further elucidated the nature of the crystal plane effect on Co3O4 surfaces and attributed the reactivity to the surface reducibility.Our results suggest that CO oxidation catalyzed by Co3O4 nanocrystals has a strong crystal plane effect and structure sensitivity.Lowering the vacancy formation energy of the oxide surface is key for high CO oxidation reactivity. 展开更多
关键词 Carbon monoxide oxidation Cobalt oxide Crystal plane effect Ion-pair active center
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In situ studies on ceria promoted cobalt oxide for CO oxidation 被引量:3
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作者 Weiwei Huan Jie Li +1 位作者 Jiahui Ji Mingyang Xing 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第5期656-663,共8页
In situ studies of catalysts play valuable roles in observing phase transformation, understanding the corresponding surface chemistry and the mechanism of the reaction. In this paper, ceria promoted cobalt oxide was p... In situ studies of catalysts play valuable roles in observing phase transformation, understanding the corresponding surface chemistry and the mechanism of the reaction. In this paper, ceria promoted cobalt oxide was prepared by the calcination method and investigated for the CO oxidation. The microstructure and morphology of CeO2-Co3O4 were investigated by the Scanning Electron Microscope, High-resolution transmission electron microscopy, Raman and X-ray photoelectron spectroscopy characterization. The effect of CeO2 doping on Co3O4 for CO oxidation was characterized by in situ X-ray Diffraction (in situ XRD) and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS). In situ XRD was carried out under H2 atmosphere to evaluate the redox property of catalysts. The results indicated that the ceria doping can enhance the reducibility of Co2+ and promote the Co3+-Co2+-Co3+ cycle, owing to the oxygen replenish property of CeO2. Furthermore, adsorbed carbonate species on the surface of CeO2-Co3O4 were investigated by in situ-DRIFTS experiment. It was turned out that carbonate species on ceria promoted cobalt oxide catalysts showed different IR peaks compared with pure cobalt oxide. The carbonate species on ceria promoted catalyst are more active, and similar to free state carbonate species with weak bonding to catalyst surface, which can effectively inhibit catalyst inactivation. This study revealed the mechanism of ceria promoting CO oxidation over cobalt oxide, which will provide theoretical support for the design of efficient CO oxidation catalysts. 展开更多
关键词 CeO2-Co3O4 CO oxidation In situ X-ray diffraction In situ diffuse reflectance infrared Fourier transform spectroscopy Carbonate species
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Preparation and catalytic behavior of reduced graphene oxide supported cobalt oxide hybrid nanocatalysts for CO oxidation 被引量:4
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作者 Yan WANG Ze-hua CHEN +6 位作者 Jing HUANG Gao-jie LI Jian-liang CAO Bo ZHANG Xing-ying CHEN Huo-li ZHANG Lei JIA 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2018年第11期2266-2274,共9页
The reduced graphene oxide (rGO) supported cobalt oxide nanocatalysts were prepared by the conventional precipitationand hydrothermal method. The as-prepared rGO-Co3O4 was characterized by the XRD, Raman spectrum, S... The reduced graphene oxide (rGO) supported cobalt oxide nanocatalysts were prepared by the conventional precipitationand hydrothermal method. The as-prepared rGO-Co3O4 was characterized by the XRD, Raman spectrum, SEM, TEM, N2-sorption,UV-Vis, XPS and H2-TPR measurements. The results show that the spinel cobalt oxide nanoparticles are highly fragmented on therGO support and possess uniform particle size, and the as-prepared catalysts possess high specific surface area and narrow pore sizedistribution. The catalytic properties of the as-prepared rGO-Co3O4 catalysts for CO oxidation were evaluated through acontinuous-flow fixed-bed microreactor-gas chromatograph system. The catalyst with 30% (mass fraction) reduced graphene oxideexhibits the highest activity for CO complete oxidation at 100 ℃. 展开更多
关键词 reduced graphene oxide cobalt oxide CATALYST CO oxidation catalytic activity
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A highly efficient flower-like cobalt catalyst for electroreduction of carbon dioxide 被引量:6
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作者 Gang Yang Zhipeng Yu +1 位作者 Jie Zhang Zhenxing Liang 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2018年第5期914-919,共6页
Electrochemical conversion of CO2 into fuel has been regarded as a promising approach to achieve the global carbon cycle.Herein,we report an efficient cobalt catalyst with a unique flower-like morphology synthesized b... Electrochemical conversion of CO2 into fuel has been regarded as a promising approach to achieve the global carbon cycle.Herein,we report an efficient cobalt catalyst with a unique flower-like morphology synthesized by a green and facile hydrothermal method,in which n-butylamine is used as the capping agent.The resultant catalyst shows superior electrocatalytic activity toward CO2 electroreduction,which is highly selective for generating formate with a Faraday efficiency of 63.4%.Electrochemical analysis reveals that the oxide on the surface is essential for the electrocatalysis of the CO2 reduction reaction.Cyclic voltammograms further suggest that this catalyst is highly active for the oxidation of reduced product,and can thus be seen as a bifunctional catalyst. 展开更多
关键词 CO2 electroreduction reaction COBALT Flower-like morphology FORMATE Interface
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Preparation of ultrafine WC-10Co composite powders by reduction and carbonization 被引量:2
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作者 申婷婷 肖代红 +3 位作者 欧小琴 宋旼 李秀秀 贺跃辉 《Journal of Central South University》 SCIE EI CAS 2013年第8期2090-2095,共6页
A solid state synthesis of ultrafine/nanocrystalline WC-10Co composite powders was reported from WO3 , Co3O4 and carbon powders after reduction and carburization at relatively low temperatures in a short time under pu... A solid state synthesis of ultrafine/nanocrystalline WC-10Co composite powders was reported from WO3 , Co3O4 and carbon powders after reduction and carburization at relatively low temperatures in a short time under pure H2 atmosphere. The effects of ball milling time and reaction temperature on the preparation of ultrafine/nanocrystalline WC-Co composite powders were studied using X-ray diffraction and scanning electron microscope (SEM). The results show that fine mixed oxide powders (WO3 , Co3O4 and carbon powders) can be obtained by long time ball milling. Increasing the reaction temperature can decrease the formation of Co3W3C and graphite phases and increase the WC crystallite size. Long-time ball milling and high reaction temperature are favorable to obtain fine and pure composite powders consisting of nanocrystalline WC from WO3 , Co3O4 and carbon powders. 展开更多
关键词 WC-10Co ball milling REDUCTION CARBURIZATION
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Microwave absorbing characteristics and temperature increasing behavior of basic cobalt carbonate in microwave field
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作者 刘秉国 彭金辉 +4 位作者 张利波 SRINIVASAKANNAN C 黄铭 张泽彪 郭胜惠 《Journal of Central South University》 SCIE EI CAS 2010年第6期1211-1215,共5页
The microwave absorbing characteristics of basic cobalt carbonate,cobalt oxide(Co3O4),and the mixture of basic cobalt carbonate and cobalt oxide were investigated by means of microwave cavity perturbation,their temper... The microwave absorbing characteristics of basic cobalt carbonate,cobalt oxide(Co3O4),and the mixture of basic cobalt carbonate and cobalt oxide were investigated by means of microwave cavity perturbation,their temperature increasing curves were measured,and their ability to absorb microwave energy was also assessed based on the temperature increasing behavior of the material exposed to microwave field.Analyses of spectrum attenuation and relative frequency shift show that basic cobalt carbonate has weak capability to absorb microwave energy,while cobalt oxide has very strong capability to absorb microwave energy.It is feasible to thermally decompose basic cobalt carbonate though addition of small amount of cobalt oxide in microwave fields.The capability to absorb microwave energy of sample increases with an increase in mixing ratio of Co3O4. 展开更多
关键词 basic cobalt carbonate cobalt oxide (Co3O4) MICROWAVE temperature increasing behavior absorption
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Synthesis and Characterization of Cobalt-Carbon Core-Shell Microspheres in Supercritical Carbon Dioxide System
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作者 Jun-song Yang Qian-wang Chen 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 北大核心 2008年第1期76-80,共5页
The synthesis of cobalt-carbon core-shell microspheres in supercritical carbon dioxide system was investi- gated. Cobalt-carbon core-shell microspheres with diameter of about 1μm were prepared at 350 ℃ for 12 h in a... The synthesis of cobalt-carbon core-shell microspheres in supercritical carbon dioxide system was investi- gated. Cobalt-carbon core-shell microspheres with diameter of about 1μm were prepared at 350 ℃ for 12 h in a closed vessel containing an appropriate amount of bis(cyclopentadienyl)cobalt powder and dry ice. Characterization by a variety of techniques, including X-ray powder diffraction, X-ray photoelectron spectroscopy, TransmissiOn electron microscope, Fourier transform infrared spectrum and Raman spectroscopy analysis reveals that each cobalt-carbon core-shell microsphere is made up of an amorphous cobalt core with diameter less than 1 μm and an amorphous carbon shell with thickness of about 200 nm. The possible growth mechanism of cobalt-carbon core-shell microspheres is discussed, based on the pyrolysis of bis(cyclopentadienyl)cobalt in supercritical carbon dioxide and the deposition of carbon or carbon clusters with odd electrons on the surface of magnetic cobalt cores due to magnetic attraction. Magnetic measurements show 141.41 emu/g of saturation magnetization of a typical sample, which is lower than the 168 emu/g of the corresponding metal cobalt bulk material. This is attributed to the considerable mass of the carbon shell and amorphous nature of the magnetic core. Control of magnetism in the cobalt-carbon core-shell microspheres was achieved by annealing treatments. 展开更多
关键词 Cobalt-carbon core-shell microspheres Supercritical carbon dioxide system
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N‐doped porous carbon nanofibers inlaid with hollow Co_(3)O_(4) nanoparticles as an efficient bifunctional catalyst for rechargeable Li‐O_(2) batteries 被引量:1
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作者 Hongbin Chen Yaqian Ye +4 位作者 Xinzhi Chen Lili Zhang Guoxue Liu Suqing Wang Liang‐Xin Ding 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2022年第6期1511-1519,共9页
Stable and high‐efficiency bifunctional catalysts for the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are desired for the practical application of Li‐O_(2)batteries with excellent rate performanc... Stable and high‐efficiency bifunctional catalysts for the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are desired for the practical application of Li‐O_(2)batteries with excellent rate performance and cycle stability.Herein,a novel hybrid bifunctional catalyst with carbon nanofibers inlaid with hollow Co_(3)O_(4)nanoparticles and separate active sites for ORR and OER were prepared and applied in Li‐O_(2)batteries.Benefiting from the synergistic effect of unique porous structural features and high electrocatalytic activity of hollow Co3O4 intimately bound to N‐doped carbon nanofibers,the assembled Li‐O_(2)batteries with novel catalyst exhibited high specific capacity,excellent rate capability,and cycle stability up to 150 cycles under a capacity limitation of 500 mAh g^(–1)at a current density of 100 mA g^(–1).The facile synthesis and preliminary results in this work show the as‐prepared catalyst as a promising bifunctional electrocatalyst for applications in metal‐air batteries,fuel cells,and electrocatalysis. 展开更多
关键词 Li‐O_(2)batteries Bifunctional catalyst Co_(3)O_(4) N‐doped carbon nanofibers Oxygen reduction reaction Oxygen evolution reaction
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Effect of alkali metals on the performance of CoCu/TiO_2 catalysts for CO_2 hydrogenation to long-chain hydrocarbons 被引量:4
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作者 Zhibiao Shi Haiyan Yang +7 位作者 Peng Gao Xinqing Chen Hongjiang Liu Liangshu Zhong Hui Wang Wei Wei Yuhan Sun 3a] 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2018年第8期1294-1302,共9页
CoCu/TiO_2 catalysts promoted using alkali metals(Li, Na, K, Rb, and Cs) were prepared by the homogeneous deposition-precipitation method followed by the incipient wetness impregnation method. The influences of the ... CoCu/TiO_2 catalysts promoted using alkali metals(Li, Na, K, Rb, and Cs) were prepared by the homogeneous deposition-precipitation method followed by the incipient wetness impregnation method. The influences of the alkali metals on the physicochemical properties of the CoCu/TiO_2 catalysts and the catalytic performance for CO_2 hydrogenation to long-chain hydrocarbons(C_(5+))were investigated in this work. According to the characterization of the catalysts based on X-ray photoelectron spectroscopy, X-ray diffraction, CO_2 temperature-programmed desorption(TPD), and H_2-TPD, the introduction of alkali metals could increase the CO_2 adsorption and decrease the H_2 chemisorption, which could suppress the formation of CH_4, enhance the production of C_(5+), and decrease the hydrogenation activity. Among all the promoters, the Na-modified CoCu/TiO_2 catalyst provided the maximum C_(5+) yield of 5.4%, with a CO_2 conversion of 18.4% and C_(5+) selectivity of42.1%, because it showed the strongest basicity and a slight decrease in the amount of H_2 desorption;it also exhibited excellent catalytic stability of more than 200 h. 展开更多
关键词 Carbon dioxide hydrogenation Long-chain hydrocarbons Carbon dioxide Fischer-Tropsch synthesis Alkali metal promoters Cobalt-coper based catalysts
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Infrared Photodissociation Spectroscopic and Theoretical Study of [Co(CO2)n]+ Clusters
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作者 Dong Yang Ming-zhi Su +4 位作者 Hui-jun Zheng Zhi Zhao Gang Li Xiang-tao Kong Hua Xie 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2019年第2期223-228,I0003,共7页
The mass-selected infrared photodissociation (IRPD) spectroscopy was utilized to investigate the interactions of cationic cobalt with carbon dioxide molecules. Quantum chemical calculations were performed on the [Co(C... The mass-selected infrared photodissociation (IRPD) spectroscopy was utilized to investigate the interactions of cationic cobalt with carbon dioxide molecules. Quantum chemical calculations were performed on the [Co(CO2)n]^+ clusters to identify the structures of the low-lying isomers and to assign the observed spectral features. All the [Co(CO2)n]^+(n=2-6) clusters studied here show resonances near the CO2 asymmetric stretch of free CO2 molecule. Experimental and calculated results indicate that the CO2 molecules are weakly bound to the Co+ cations in an end-on con guration via a charge-quadrupole electrostatic interaction. The present IRPD spectra of [Co(CO2)n]^+ clusters have been compared to those of Ar-tagged species ([Co(CO2)n]^+-Ar), which would provide insights into the tagging effect of rare gas on the weakly-bounded clusters. 展开更多
关键词 Cationic cobalt Carbon dioxide Structure Infrared photodissociation spectroscopy Quantum chemical calculation
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Boron-Promoted Co-Catalyzed N-Methylation of Secondary Aromatic Amines with CO_(2) and H_(2)
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作者 Shi Qin Li Zhen +2 位作者 He Lin Li Yudong Li Yuehui 《有机化学》 SCIE CAS 2024年第10期3233-3240,共8页
Development of catalytic methods using CO_(2)/H_(2) as methylating reagent for selective methylation of amines is highly attractive.Herein,the methylation of N—H bond via boron promoted activation of Co-formate inter... Development of catalytic methods using CO_(2)/H_(2) as methylating reagent for selective methylation of amines is highly attractive.Herein,the methylation of N—H bond via boron promoted activation of Co-formate intermediates is reported.This catalytic system showed excellent functional group tolerance with high catalytic activity,and a series of methylated products were acquired in moderate to excellent yields under mild conditions(e.g.80℃ or 60℃).It was inferred that imine complex C was the crucial intermediate formed via dehydration of species B,providing efficient C—N coupling for the selective N-methylation of secondary aromatic amines with CO_(2)/H_(2). 展开更多
关键词 CO_(2)/H_(2) N-methylation cobalt catalysis
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Advanced non-precious electrocatalyst of the mixed valence CoO_x nanocrystals supported on N-doped carbon nanocages for oxygen reduction 被引量:5
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作者 Sheng Chen Liwei Wang +8 位作者 Qiang Wu Xiang Li Yu Zhao Hongwei Lai Lijun Yang Tao Sun Yi Li Xizhang Wang Zheng Hu 《Science China Chemistry》 SCIE EI CAS CSCD 2015年第1期180-186,共7页
Taking advantage of the nitrogen(N)-participation and large surface area of N-doped carbon nanocages(NCNCs),the Co Ox nanocrystals are conveniently immobilized onto the NCNCs with high dispersion.The Co Ox/NCNCs hybri... Taking advantage of the nitrogen(N)-participation and large surface area of N-doped carbon nanocages(NCNCs),the Co Ox nanocrystals are conveniently immobilized onto the NCNCs with high dispersion.The Co Ox/NCNCs hybrid exists in the mixed valence with predominant Co O over Co3O4 and demonstrates superb oxygen reduction reaction activity and stability remaining^94%current density even after operation over 100 h.These results suggest a promising strategy to develop advanced electrocatalysts with the novel NCNCs or even beyond. 展开更多
关键词 cobalt oxide nanocrystals fuel cells non-precious electrocatalysts nitrogen doped carbon nanocages oxygen reductionreaction
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Hierarchical CuCo_2O_4@nickel-cobalt hydroxides core/shell nanoarchitectures for high-performance hybrid supercapacitors 被引量:6
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作者 Chenggang Wang Kai Guo +5 位作者 Weidong He Xiaolong Deng Peiyu Hou Fuwei Zhuge Xijin Xu Tianyou Zhai 《Science Bulletin》 SCIE EI CAS CSCD 2017年第16期1122-1131,共10页
Ni0.5Co0.5(OH)2 nanosheets coated CuCo2O4 nanoneedles arrays were successfully designed and synthe- sized on carbon fabric. The core/shell nanoarchitectures directly served as the binder-free electrode with a superi... Ni0.5Co0.5(OH)2 nanosheets coated CuCo2O4 nanoneedles arrays were successfully designed and synthe- sized on carbon fabric. The core/shell nanoarchitectures directly served as the binder-free electrode with a superior capacity of 295.6 mAh g-1 at 1 Ag-1, which still maintained 220 mAh g-1 even at the high current density of 40 A g-l, manifesting their enormous potential in hybrid supercapacitor devices. The asassembled CuCo2O4@Ni0.5Co0.5(OH)2]]AC hybrid supercapacitor device exhibited favorable properties with the specific capacitance as high as 90 F g 1 at 1 A g-1 and the high energy density of 32 Wh kg 1 at the power density of 800 Wkg-1. Furthermore, the as-assembled device also delivered excellent cycling performance (retaining 91.9% of the initial capacitance after 12,000 cycles at 8 A g 1) and robust mechanical stability and flexibility, implying the huge potential of present hierarchical electrodes in energy storage devices. 展开更多
关键词 Spinel CuCo2O4 Nickel-cobalt hydroxides Hybrid supercapacitors Hydrothermal method Electrodeposition
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