Selective photocatalytic CO2 reduction to CH4 by two-dimensional Ni-MOF
Converting CO2 into CH4 by solar energy can relieve energy crisis and greenhouse effect.In this study,two-dimensional(2D)metal organic frameworks(MOF),Cu-BDC(BDC=1,4-benzenedicarboxylate)and Ni-BDC were successfully prepared by the reaction of terephthalic acid(H2BDC)and cuprum(Cu)or nickel(Ni)salt through ultrasonic treatment.The structure and the morphology were well represented by X-ray diffraction,X-ray photoelectron spectroscopy and electron microscopes.The photoelectric properties were investigated by UV-visible diffuse reflectance spectrum,impedance,and photocurrent response.Under simulated sunlight,Ni-BDC could be used as photocatalyst for CO2 to CH4 conversion,showing excellent efficiency with a CH4 production rate as high as 95.22 μmol·g-1·h-1,a selectivity of 75%,and perfect stability,which was superior to Cu-BDC.This was attributed to the more negative conduction band position for n-type semiconductor Ni-BDC,which was beneficial to improve the efficiency of photo-generated electrons.The results show that the selection of metal active centers can effectively regulate the photocatalytic performance of MOF.
metal organic frameworkphotocatalysisCO2 reductionCH4
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