Acidic chloride electrolyte mediates the high conversion ratio of CO2-to-C2H4 and direct production of Cl2

Abstract

Electrochemical CO₂ reduction (CO₂R) in acidic electrolytes can effectively overcome the challenge of carbonate formation and poor carbon utilization efficiency of CO₂R in alkaline and neutral electrolytes. The corresponding anodic reaction design in an acidic environment therefore becomes important to overcome the valueless products and high energy consumption of the oxygen evolution reaction (OER) that hinder the overall commercial value of CO₂R systems. Herein, we designed an efficient coupling system of electrochemical CO₂ reduction and chlorine oxidation in an acidic electrolyte to reduce CO₂ loss and improve the sustainability of the reaction system. We modulated the local microenvironment to promote C–C coupling by combining the cation effect with the larger surface area CuO nanoparticle catalyst in an acidic electrolyte. As a result, this coupling system can achieve high C₂H₄ and Cl₂ faradaic efficiencies (FEs) of 63% and 89% at 700 mA cm⁻² simultaneously. The system is commercially promising as it stably produces valuable products at both the cathode and anode.