Provskite-type catalysts, Ln0.6 Sr0.4 FexCo1-x O3 (Ln = Nd,Pr, Gd, Sm, La, 0＜x＜1) and Ln0.8Na0.2CoO3(Ln= La,Gd, Sm) were synthesized, their catalytic properties in the oxidative coupling of methane (OCM) were examin...Provskite-type catalysts, Ln0.6 Sr0.4 FexCo1-x O3 (Ln = Nd,Pr, Gd, Sm, La, 0＜x＜1) and Ln0.8Na0.2CoO3(Ln= La,Gd, Sm) were synthesized, their catalytic properties in the oxidative coupling of methane (OCM) were examined in a fixed-bed reactor. The former group presented higher activity in the OCM, but the main product was carbon dioxide. While the later group showed lower activity but much higher selectivity to C2 hydrocarbons compared with the former. Electrochemical measurements were conducted in a solid oxide membrane reactor with La0.8 Na0.2CoO3 as catalyst. The results showed that methane was oxidized to carbon dioxide and ethane by two parallel reactions. Ethane was oxidized to ethene and carbon dioxide. A fraction of ethene was oxidized deeply to carbon dioxide. The total selectivity to C2 hydrocarbons exceeded 70%. Based on the experimental results, a kinetic model was suggested to describe the reaction results.展开更多
Solar‐driven conversion of carbon dioxide,water and nitrogen into high value‐added fuels(e.g.H_(2),CO,CH_(4),CH_(3)OH,NH_(3) and so on)is regarded as an environmental‐friendly and ideal route for relieving the gree...Solar‐driven conversion of carbon dioxide,water and nitrogen into high value‐added fuels(e.g.H_(2),CO,CH_(4),CH_(3)OH,NH_(3) and so on)is regarded as an environmental‐friendly and ideal route for relieving the greenhouse gas effect and countering energy crisis,which is an attractive and challenging topic.Hence,various types of photocatalysts have been developed successively to meet the requirements of these photocatalysis.Among them,cobalt‐based heterogeneous catalysts emerge as one of the most promising photocatalysts that open up alluring vistas in the field of solar‐to‐fuels conversion,which can effectively enhance photocatalytic efficiency by extending light absorption range,promoting charge separation,providing active sites,and lowering reaction barrier.In this review,we first present the working principles of cobalt‐based heterogeneous catalysts for photocatalytic water splitting,CO_(2) reduction,and N_(2) fixation.Second,five efficient strategies including surface modification,morphology modulation,crystallinity controlling,crystal engineering and doping,are discussed for improving the photocatalytic performance with different types cobalt‐based catalysts(cobalt nanoparticles and single atom,oxides,sulfides,phosphides,MOFs,COFs,LDHs,carbide,and nitrides).Third,we outline the applications for the state‐of‐the‐art photocatalytic CO_(2) reduction and water splitting,and nitrogen fixation over cobalt‐based heterogeneous catalysts.Finally,the central challenges and possible improvements of cobalt‐based photocatalysis in the future are presented.The purpose of this review is to summarize the past experience and lessons,and provide reference for the further development of cobalt‐based photocatalysis technology.展开更多
The immobilized nickel(II) on the organic-inorganic hybrid material was prepared and used as an effective catalyst for the Biginelli reaction.In the presence of the immobilized nickel catalyst,aromatic aldehydes react...The immobilized nickel(II) on the organic-inorganic hybrid material was prepared and used as an effective catalyst for the Biginelli reaction.In the presence of the immobilized nickel catalyst,aromatic aldehydes reacted with ethyl acetoacetate and urea (or thiourea) smoothly to generate the corresponding Biginelli products in good to excellent yields without using any additive.The work-up procedure is very simple and practical.Furthermore,the silica-supported nickel(II) could be recovered and recycled for six consecutive trials without significant loss of its catalytic activity.展开更多
基金Supported by the National Natural Science Foundation of China (20773038, 20902023)the National Basic Research Program of China (973 Program, 2009CB724706, 2009ZX09501-016)+1 种基金the China National Special Fund for State Key Laboratory of Bioreactor Engineering (2060204)the Shanghai Leading Academic Discipline Project (B505)
基金This work was supported supported by the Center Petrochemical Company of China (X599027).
文摘Provskite-type catalysts, Ln0.6 Sr0.4 FexCo1-x O3 (Ln = Nd,Pr, Gd, Sm, La, 0＜x＜1) and Ln0.8Na0.2CoO3(Ln= La,Gd, Sm) were synthesized, their catalytic properties in the oxidative coupling of methane (OCM) were examined in a fixed-bed reactor. The former group presented higher activity in the OCM, but the main product was carbon dioxide. While the later group showed lower activity but much higher selectivity to C2 hydrocarbons compared with the former. Electrochemical measurements were conducted in a solid oxide membrane reactor with La0.8 Na0.2CoO3 as catalyst. The results showed that methane was oxidized to carbon dioxide and ethane by two parallel reactions. Ethane was oxidized to ethene and carbon dioxide. A fraction of ethene was oxidized deeply to carbon dioxide. The total selectivity to C2 hydrocarbons exceeded 70%. Based on the experimental results, a kinetic model was suggested to describe the reaction results.
文摘Solar‐driven conversion of carbon dioxide,water and nitrogen into high value‐added fuels(e.g.H_(2),CO,CH_(4),CH_(3)OH,NH_(3) and so on)is regarded as an environmental‐friendly and ideal route for relieving the greenhouse gas effect and countering energy crisis,which is an attractive and challenging topic.Hence,various types of photocatalysts have been developed successively to meet the requirements of these photocatalysis.Among them,cobalt‐based heterogeneous catalysts emerge as one of the most promising photocatalysts that open up alluring vistas in the field of solar‐to‐fuels conversion,which can effectively enhance photocatalytic efficiency by extending light absorption range,promoting charge separation,providing active sites,and lowering reaction barrier.In this review,we first present the working principles of cobalt‐based heterogeneous catalysts for photocatalytic water splitting,CO_(2) reduction,and N_(2) fixation.Second,five efficient strategies including surface modification,morphology modulation,crystallinity controlling,crystal engineering and doping,are discussed for improving the photocatalytic performance with different types cobalt‐based catalysts(cobalt nanoparticles and single atom,oxides,sulfides,phosphides,MOFs,COFs,LDHs,carbide,and nitrides).Third,we outline the applications for the state‐of‐the‐art photocatalytic CO_(2) reduction and water splitting,and nitrogen fixation over cobalt‐based heterogeneous catalysts.Finally,the central challenges and possible improvements of cobalt‐based photocatalysis in the future are presented.The purpose of this review is to summarize the past experience and lessons,and provide reference for the further development of cobalt‐based photocatalysis technology.
基金financial support by the National Natural Science Foundation of China (20972057, 20772043)the Excellent Scientist Foundation of Anhui Province, China (04046080)the Natural Science Foundation of Anhui Province's Higher Education, China (KJ2009B212Z)
文摘The immobilized nickel(II) on the organic-inorganic hybrid material was prepared and used as an effective catalyst for the Biginelli reaction.In the presence of the immobilized nickel catalyst,aromatic aldehydes reacted with ethyl acetoacetate and urea (or thiourea) smoothly to generate the corresponding Biginelli products in good to excellent yields without using any additive.The work-up procedure is very simple and practical.Furthermore,the silica-supported nickel(II) could be recovered and recycled for six consecutive trials without significant loss of its catalytic activity.
