Improving the activity of electrochemical reduction of CO2 to C1 products by oxidation derived copper catalyst

Cu -based electrocatalysts have become the focus in the field of electrochemical CO2 reduction reaction (ECO2RR) due to their ability to produce multicarbon products. However, the research on generating single carbon products with higher economic feasibility via ECO2RR based on Cu -based electrocatalysts is rather rare, and the roles of the surface architecture and oxides of the electrocatalysts have not been explained exactly. In this work, a two-step method including thermal oxidation and electroreduction is proposed to introduce Cu+ into pure Cu foil to form Cu2O/Cu electrocatalyst. By regulating the surface composition and morphology of the electrocatalyst in this way, the activity of ECO2RR to C1 products has been greatly improved. The Faradaic efficiency of carbon products of the Cu2O/Cu electrode reaches 84% at -0.7 V vs. RHE with good selectivity for HCOOH and CO. The current density of Cu2O/Cu electrode reaches -12.21 mA cm -2 at -0.8 V vs. RHE, which is much higher than that of the Cu foil electrode (-0.09 mA cm -2). In -situ Raman characterization shows that Cu+ in Cu2O/Cu electrode could inhibit hydrogen generation and promote ECO2RR by stabilizing the adsorption of CO2.