Enhanced C–C coupling of Cu-based catalysts via zirconia-driven carbonate interaction for electrochemical CO2 reduction reaction

Abstract

Electrochemical CO₂ reduction (ECR) using Cu-based catalysts is a promising approach for producing C₂₊ chemicals such as C₂H₄ for sustainable carbon capture and utilization. Recent research has explored improving Cu catalyst performances through modifications, including integrating with other metal oxides. Here, we report that incorporating amorphous zirconia adjacent to copper oxide (CuO/ZrO_x) significantly improves its ECR performance in a membrane electrode assembly (MEA) electrolyzer. The CuO/ZrO_x catalyst exhibited a higher CO₂ adsorption capacity and increased current density for C₂₊ production compared to bare CuO. Specifically, the ethylene partial current density increased by 1.76 times. Operando X-ray absorption spectroscopy measurements reveal the evolution of the zirconia–carbonate interaction during ECR in the MEA, whereas the Cu state is reduced to the metallic state, irrespective of ZrO₂ presence. Post-reaction analysis shows that the modulation in the binding environment of Cu is associated with an increased oxidation state of Cu along with the enhanced interaction of CuO/ZrO_x with carbonate. These distinct properties support the role of zirconia in enhancing CO₂ affinity and mediating the reactant feed to the Cu-based catalyst surface.