Oxidative coupling of methane to ethylene is of high importance to the future of light olefin industry.However,the carbon atom efficiency is normally below 50%in gas phase reaction which is limited to the overoxidatio...Oxidative coupling of methane to ethylene is of high importance to the future of light olefin industry.However,the carbon atom efficiency is normally below 50%in gas phase reaction which is limited to the overoxidation of methane to carbon dioxide with oxidants.Here we present an alternative approach of electrochemical oxidation of methane in an oxygen permeation membrane reactor and show the highest conversion of methane and C2 selectivity of 28%and 40.2%at 1150℃,respectively.We prepare the 100-μm-thick perovskite(La0.8 Sr0.2)1-x Cr0.5 Fe0.5 O3-δ(LSCrF)dense membrane(La0.8 Sr0.2)1-xCr0.5 Fe0.5O3-δ(LSCrF–Fe)(x=0,0.02,0.05 and 0.10)scaffolds while the excess of Fe would be exsolved on porous skeleton to create metal-oxide interfaces toward methane oxidation.The metal-oxide interfaces not only facilitate the activation of C–H bond in methane but also enhance the coking resistance.展开更多
A series of novel dense mixed conducting ceramic membranes based on K2NiF4-type(La1-xCax)2(Ni0.75Cu0.25)O4+δwas successfully prepared through a sol-gel route.Their chemical compatibility,oxygen permeability,CO and CO...A series of novel dense mixed conducting ceramic membranes based on K2NiF4-type(La1-xCax)2(Ni0.75Cu0.25)O4+δwas successfully prepared through a sol-gel route.Their chemical compatibility,oxygen permeability,CO and CO2 tolerance,and long-term CO2 resistance regarding phase composition and crystal structure at different atmospheres were studied.The results show that higher Ca contents in the material lead to the formation of CaCO3.A constant oxygen permeation flux of about 0.63 mL·min−1·cm−2 at 1173 K through a 0.65 mm thick membrane was measured for(La0.9Ca0.1)2(Ni0.75Cu0.25)O4+δ,using either helium or pure CO2 as sweep gas.Steady oxygen fluxes with no sign of deterioration of this membrane were observed with increasing CO2 concentration.The membrane showed excellent chemical stability towards CO2 for more than 1360 h and phase stability in presence of CO for 4 h at high temperature.In addition,this membrane did not deteriorate in a high-energy CO2 plasma.The present work demonstrates that this(La0.9Ca0.1)2(Ni0.75Cu0.25)O4+δmembrane is a promising chemically robust candidate for oxygen separation applications.展开更多
基金Supported by the National Key Research and Development Program of China(2017YFA0700102)National Natural Science Foundation of China(91845202)+1 种基金Dalian National Laboratory for Clean Energy(DNL180404)Strategic Priority Research Program of Chinese Academy of Sciences(XDB2000000)。
文摘Oxidative coupling of methane to ethylene is of high importance to the future of light olefin industry.However,the carbon atom efficiency is normally below 50%in gas phase reaction which is limited to the overoxidation of methane to carbon dioxide with oxidants.Here we present an alternative approach of electrochemical oxidation of methane in an oxygen permeation membrane reactor and show the highest conversion of methane and C2 selectivity of 28%and 40.2%at 1150℃,respectively.We prepare the 100-μm-thick perovskite(La0.8 Sr0.2)1-x Cr0.5 Fe0.5 O3-δ(LSCrF)dense membrane(La0.8 Sr0.2)1-xCr0.5 Fe0.5O3-δ(LSCrF–Fe)(x=0,0.02,0.05 and 0.10)scaffolds while the excess of Fe would be exsolved on porous skeleton to create metal-oxide interfaces toward methane oxidation.The metal-oxide interfaces not only facilitate the activation of C–H bond in methane but also enhance the coking resistance.
基金This work is part of the project “Plasma-induced CO2-conversion”(PiCK,project number:03SFK2S3B)and financially supported by the German Federal Ministry of Education and Research in the framework of the“Kopemikus projects for the Energiewende”.The authors are thankfUl to B.Sc.Laura Steinle(University of Stuttgart)for her assistance during the CO stability tests,and Christine Stefani and Prof.Dr.Robert Dinnebier(Max Planck Institute for Solid State Research,Stuttgart)for the in situ PXRD measurements,respectively.G.C.thanks Frank Hack and Dr.Angelika Veziridis for their kind support during experiments and discussions.
文摘A series of novel dense mixed conducting ceramic membranes based on K2NiF4-type(La1-xCax)2(Ni0.75Cu0.25)O4+δwas successfully prepared through a sol-gel route.Their chemical compatibility,oxygen permeability,CO and CO2 tolerance,and long-term CO2 resistance regarding phase composition and crystal structure at different atmospheres were studied.The results show that higher Ca contents in the material lead to the formation of CaCO3.A constant oxygen permeation flux of about 0.63 mL·min−1·cm−2 at 1173 K through a 0.65 mm thick membrane was measured for(La0.9Ca0.1)2(Ni0.75Cu0.25)O4+δ,using either helium or pure CO2 as sweep gas.Steady oxygen fluxes with no sign of deterioration of this membrane were observed with increasing CO2 concentration.The membrane showed excellent chemical stability towards CO2 for more than 1360 h and phase stability in presence of CO for 4 h at high temperature.In addition,this membrane did not deteriorate in a high-energy CO2 plasma.The present work demonstrates that this(La0.9Ca0.1)2(Ni0.75Cu0.25)O4+δmembrane is a promising chemically robust candidate for oxygen separation applications.
