Achieving high catalytic performance with lower possible cost and higher energetic efficiency is critical for catalytic oxidation of volatile organic compounds(VOCs).However,traditional thermocatalysts generally under...Achieving high catalytic performance with lower possible cost and higher energetic efficiency is critical for catalytic oxidation of volatile organic compounds(VOCs).However,traditional thermocatalysts generally undergo low catalytic activity and fewer active sites.Herein,this paper synthesizes nearly all-surface-atomic,ultrathin two-dimensional(2D)Co_(3)O_(4) nanosheets to address these problems through offering a numerous active sites and high electron mobility.The 2D Co_(3)O_(4) nanosheets(1.70 nm)exhibit catalyzation to the total oxidation of n-hexanal at the lower temperature of r90%=202℃,and at the space velocity of 5.0×10^(4) h^(-1).It is over 1.2 and 6 times higher catalytic activity than that of 2D CoO nanosheets(1.71 nm)and bulk Co_(3)O_(4) counterpart,respectively.Transient absorption spectroscopy analysis shows that the oxygen vacancy defect traps electrons,thereby preventing the recombination with holes,increasing the lifetime of electrons,and making electron-holes reach a nondynamic equilibrium.The longer the electron lifetime is,the easier the oxygen vacancy defects capture electrons.Furthermore,the defects combine with oxygen to form active oxygen components.Compared with the lattice oxygen involved in the reaction of bulk Co_(3)O_(4),the nanosheets change the catalytic reaction path,which effectively reduces the activation energy barrier from 34.07 to 27.15 kJ/mol.The changed surface disorder,the numerous coordinatively-unsaturated Co atoms and the high ratio of O_(ads)/O_(lat) on the surface of 2D Co_(3)O_(4) nanosheets are responsible for the catalytic performance.展开更多
基金supported by National Natural Science Foundation of China(Nos.51808037,21601136,and 21876010)Fundamental Research Funds for the Central Universities(No.FRF-TP-16-060A1)Natural Science Foundation of Guangdong Province(No.2020A1515011197).
文摘Achieving high catalytic performance with lower possible cost and higher energetic efficiency is critical for catalytic oxidation of volatile organic compounds(VOCs).However,traditional thermocatalysts generally undergo low catalytic activity and fewer active sites.Herein,this paper synthesizes nearly all-surface-atomic,ultrathin two-dimensional(2D)Co_(3)O_(4) nanosheets to address these problems through offering a numerous active sites and high electron mobility.The 2D Co_(3)O_(4) nanosheets(1.70 nm)exhibit catalyzation to the total oxidation of n-hexanal at the lower temperature of r90%=202℃,and at the space velocity of 5.0×10^(4) h^(-1).It is over 1.2 and 6 times higher catalytic activity than that of 2D CoO nanosheets(1.71 nm)and bulk Co_(3)O_(4) counterpart,respectively.Transient absorption spectroscopy analysis shows that the oxygen vacancy defect traps electrons,thereby preventing the recombination with holes,increasing the lifetime of electrons,and making electron-holes reach a nondynamic equilibrium.The longer the electron lifetime is,the easier the oxygen vacancy defects capture electrons.Furthermore,the defects combine with oxygen to form active oxygen components.Compared with the lattice oxygen involved in the reaction of bulk Co_(3)O_(4),the nanosheets change the catalytic reaction path,which effectively reduces the activation energy barrier from 34.07 to 27.15 kJ/mol.The changed surface disorder,the numerous coordinatively-unsaturated Co atoms and the high ratio of O_(ads)/O_(lat) on the surface of 2D Co_(3)O_(4) nanosheets are responsible for the catalytic performance.
