Surface Hydroxyl-Mediated Stabilization of Cu Species in Ga-Doped CuO Catalysts for Sustained CO Electroreduction to Ethylene.

The presence of surface hydroxyl (*OH) species plays a critical role in modulating the selectivity and stability of CuO catalysts during CO electroreduction to ethylene and ethanol. However, the underlying mechanism by which *OH adsorption contributes to CuO stability remains poorly understood. In this study, we report the development of a Ga-doped CuO (Ga-CuO) catalyst, where Ga promotes the adsorption of *OH species on the catalyst surface. This enhanced *OH adsorption strengthens Cu-O interactions and improves the stability of Cu species. In situ Raman spectroscopy and theoretical calculations reveal that Ga incorporation facilitates *OH formation, which in turn increases orbital overlap between Cu 3d and O 2p orbitals. This interaction suppresses lattice oxygen leaching and contributes to the stabilization of Cu. As a result, Ga-CuO exhibits a stable ethylene production rate sustained for over 50 h, achieving a Faradaic efficiency (FE) for CH of 26.4%, which is 1.4 times higher than that of pure CuO. These findings offer mechanistic insights into the role of the catalyst microenvironment in Cu stabilization during CORR and provide valuable guidance for the rational design of more efficient and durable CO reduction catalysts.