Converting CO_(2)to ethanol on Ag nanowires with high selectivity investigated by operando Raman spectroscopy

摘要

Electrochemical conversion of CO_(2)into liquid fuels provides an efficient way to store the renewable energy in the production of fuels and chemicals.However,effectively converting CO_(2)to ethanol remains extremely challenging due to the low activity and selectivity.Herein,we achieve a high ethanol Faradaic efficiency(FE)as high as 85%on Ag nanowires(NWs)for CO_(2)electroreduction at-0.95 V.X-ray photoelectron spectroscopy and electrochemical experiments prove that such Ag NWs are partially oxidized.Operando Raman spectroscopy finds the important CO intermediate adsorbed on partially oxidized Ag NWs,facilitating the ethanol formation.Density functional theory calculations prove that the reaction energy of CO coupling with the*CHO to*COCHO intermediate on the partially oxidized Ag NWs is smaller than that on the surface of Cu,which explains why the ethanol FE of such partially oxidized Ag NWs can exceed that of Cu,and therefore is the most favorable pathway for the formation of C_(2)products on partially oxidized Ag NWs.This study provides a new insight to design efficient catalysts and investigate the mechanisms to improve the selectivity.