Efficient Electrochemical Reduction of CO ₂ to C ₂ H ₄ Over Low Work Function Cu/ZnO Film Catalysts

Cu-based catalysts for electrochemical CO₂ reduction reactions facilitate the transformation of CO₂ into economically viable multicarbon products. There remains a pressing need to design efficient, stable, and cost-effective catalysts to enhance the selectivity for these multicarbon products. Metal-oxide heterogeneous interface can modify the electronic structure of metal surfaces, influencing the adsorption energy of crucial intermediates and thereby enhancing the selectivity for multicarbon products. In this study, Cu/ZnO electrodes are prepared by magnetron sputtering to achieve a Faraday efficiency of 51.2% for C₂H₄ at -1.17 V. The Cu/ZnO heterogeneous interface provided abundant active sites for the reaction, and the lower work function facilitated the multi-electron transfer process necessary for the reduction of CO₂ to C₂H₄, thereby enhances the catalytic performance. DFT calculations reveal that the upward shift in the d-band center of Cu/ZnO, compared to pure Cu, enhances the adsorption energy of the crucial intermediate ^*CO. Moreover, the C-C coupling achieved on Cu/ZnO through the ^*CHO-^*CHO pathway, which features lower energy barriers, ensures high selectivity in the conversion of CO₂ to C₂H₄. This work provides a promising and effective strategy for the large-scale development of metal-oxide catalysts for the electrochemical reduction of CO₂ to C₂H₄.