*CO spillover induced by bimetallic xZnO@yCuO active centers for enhancing C-C coupling over electrochemical CO2 reduction

Cu-based catalysts attaining high catalytic activity and selectivity towards C2+ product remains a major obstacle, which has garnered significant attention. *CO plays a key role as an intermediate in the next process of C-C dimerization. In this study, we devise a novel approach for generating *CO in situ and facilitating its spillover to neighboring dandelion-liked CuO active sites, utilizing flower-shaped ZnO as a source of *CO intermediate. Consequently, the Zn-rich 3ZnO@CuO catalyst shows the highest Faraday efficiency of CO (FECO) is 89.94 % at -1.2 V vs. RHE. Additionally, a remarkable C2H4 selectivity of 46.37 % for ZnO@CuO at a more positive potential of -1.1 V vs. RHE is achieved. In-situ ATR-SEIRAS also unveils that *CO spillover increases the surface coverage of *CO on the catalyst, ultimately improving the selectivity for C-C coupling and C2H4 production. The relationship between structure and performance will offer guidance for the design of Cu-based catalysts with superior efficiency in CO2 reduction.