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

Abstract

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.