Selective and Low Overpotential Electrochemical CO2 Reduction to Formate on CuS Decorated CuO Heterostructure

Cu2O/CuO/CuS electrocatalyst was prepared by thermal oxidation of cleaned copper mesh in the air into Cu2O/CuO and CuS was deposited on oxide surface using facile successive ionic layer adsorption and reaction method. The successive fabrication of the electrocatalyst was confirmed using XRD, SEM, Raman and XPS. The catalytic enhancement is believed to be associated with the reduction of copper sulfide. Together with copper oxides, they offer favorable adsorption sites for electrochemical CO2 reduction. The synthesized catalyst offered significantly enhanced activity and selectivity performance for CO2 reduction at lower overpotential. Remarkably, the faradaic efficiency for formate generation reaches 84% at the potential of − 0.7 V versus RHE. It has also provided a high partial current density of − 20 mA cm− 2.