Periodic density functional theory calculations have been carried out to investigate the effect of TM atom supported on different Cu surfaces towards the activation for CO2 molecules. The most stable configuration of ...Periodic density functional theory calculations have been carried out to investigate the effect of TM atom supported on different Cu surfaces towards the activation for CO2 molecules. The most stable configuration of CO2 on various TM/Cu（TM = Fe, Co, Ni, Cu） surfaces is determined and the results show that the cobalt is potentially excellent admetal to enhance the chemisorption of CO2 on copper surfaces among the late 3 d-metals. To deep understand the adsorption property, the bond characteristics of the adsorption bonds are carefully examined by the crystal orbital Hamilton population technique and charge density difference analysis. The result reveals that the interaction between the CO2 molecule and TM/Cu surface primarily derive from the TM–C bond. Moreover, the defined adsorption bond strength（I） between CO2 and substrate could be a descriptor for TM-supported surface.展开更多
A comprehensive density functional theory calculation was employed to investigate the possible reaction pathways and mechanisms of methane complete oxidation(CH4+2O2→CO2+2H2O)on different manganese oxides including a...A comprehensive density functional theory calculation was employed to investigate the possible reaction pathways and mechanisms of methane complete oxidation(CH4+2O2→CO2+2H2O)on different manganese oxides including a-MnO2(100)and b-MnO2(111)surfaces.According to a coupling of the Mars-van Krevelen and Langmuir-Hinshelwood mechanism,the activation energy barrier and the reaction energy of each elementary surface reaction were determined.Our calculated results show that the detailed processes for methane oxidation on two surfaces are different due to the differences in the surface structure.The breaking of the last C–H bond of CH4 moleculeis the rate-determining step with an activation barrier of 0.85 eV for a-MnO2(100)surface.By contrast,the overall reaction rate on b-Mn O2(111)surface is limited by the dissociation of the second O2 molecule adsorbed on the vacancy site,and re-oxidation of the reduced b-MnO2(111)surface by the gaseous oxygen requires a much higher energy barrier of 1.44 eV.As a result,the a-Mn O2(100)exhibits superior activity and durability in the methane oxidation reaction than b-MnO2(111)surface.The present study provides insight into understanding the structure-catalytic activity relationship of the catalysts based on manganese oxides towards the methane oxidation reaction.展开更多
基金supported by the National Natural Science Foundation of China(21773030,21203027 and 21371034)
文摘Periodic density functional theory calculations have been carried out to investigate the effect of TM atom supported on different Cu surfaces towards the activation for CO2 molecules. The most stable configuration of CO2 on various TM/Cu（TM = Fe, Co, Ni, Cu） surfaces is determined and the results show that the cobalt is potentially excellent admetal to enhance the chemisorption of CO2 on copper surfaces among the late 3 d-metals. To deep understand the adsorption property, the bond characteristics of the adsorption bonds are carefully examined by the crystal orbital Hamilton population technique and charge density difference analysis. The result reveals that the interaction between the CO2 molecule and TM/Cu surface primarily derive from the TM–C bond. Moreover, the defined adsorption bond strength（I） between CO2 and substrate could be a descriptor for TM-supported surface.
基金supported by the National Natural Science Foundation of China(21773030)Natural Science Foundation of Fujian Province(2017J01409)。
文摘A comprehensive density functional theory calculation was employed to investigate the possible reaction pathways and mechanisms of methane complete oxidation(CH4+2O2→CO2+2H2O)on different manganese oxides including a-MnO2(100)and b-MnO2(111)surfaces.According to a coupling of the Mars-van Krevelen and Langmuir-Hinshelwood mechanism,the activation energy barrier and the reaction energy of each elementary surface reaction were determined.Our calculated results show that the detailed processes for methane oxidation on two surfaces are different due to the differences in the surface structure.The breaking of the last C–H bond of CH4 moleculeis the rate-determining step with an activation barrier of 0.85 eV for a-MnO2(100)surface.By contrast,the overall reaction rate on b-Mn O2(111)surface is limited by the dissociation of the second O2 molecule adsorbed on the vacancy site,and re-oxidation of the reduced b-MnO2(111)surface by the gaseous oxygen requires a much higher energy barrier of 1.44 eV.As a result,the a-Mn O2(100)exhibits superior activity and durability in the methane oxidation reaction than b-MnO2(111)surface.The present study provides insight into understanding the structure-catalytic activity relationship of the catalysts based on manganese oxides towards the methane oxidation reaction.
