Investigation of a Cu(core)/CuO(shell) catalyst for electrochemical reduction of CO₂ in aqueous soultion

In this work, we investigate the electrochemical reduction of CO₂ on a Cu(core)/CuO(shell) catalyst in aqueous electrolytes in a flow reactor. This catalyst predominantly produce CO and HCOOH, and Faradaic efficiency are 21.5% and 20.2% at -1.73 V vs.Ag/AgCl, respectively. During the process of electrochemical reduction of CO₂ in aqueous solution, a small amount of methanol is produced, Faradaic efficiency is around 1% ~ 2.5%. A study of the electrochemical behavior of Cu(core)/CuO(shell) in a standard three-electrode cell reveal transformations between Cu, Cu(I), and CuO as a function of applied potential. The results are confirmed by XPS. This interplay between different Cu oxidation states and the presence of the oxide surface to promote proton adsorption may benefit the formation of complicated products.