Optimizing C―C Coupling on Cu0/Cu+/Ga Interfaces by Enhancing Active Hydrogen Absorption for Excellent CO2-to-C2+ Electrosynthesis

The electrocatalytic reduction of CO2 (CO2RR) to high-value chemicals and fuels offers a promising route for a clean carbon cycle. However, it often suffers from low catalytic activity and poor selectivity. Heterostructure construction has been shown to be an effective strategy for producing multi-carbon products, but the synergistic mechanisms between multiple active sites resulting from the reconstruction process remain unclear. In this study, a Ga2O3/CuO heterostructure is established via a simple sol-gel method to produce C2+ products. Experimental results demonstrate that Ga2O3 stabilizes Cu+ to form Cu-0/Cu+/Ga active centers and enhances water-splitting ability during the reaction. The improved hydrogen absorption on the Ga site shifts the C & horbar;C coupling reaction pathway from *OCCO to the asymmetric *OCCHO coupling path with a lower energy barrier. As a result, the catalysts exhibit superior CO2RR performance, achieving a 70.1% C2+ Faradaic efficiency at -1.2 V-RHE in a flow cell, with ethylene Faradaic efficiency reaching 58.3% and remaining stable for 10 h.