Lowering rate-determining step energy barrier to promote electrocatalytic reduction of CO2 to multicarbon products over oxygen-rich vacancy CuO catalysts

Electrochemical carbon dioxide reduction (ECR), which converts carbon dioxide into valuable chemical substances, effectively achieves sustainable carbon neutrality. In this study, we report that CuO catalysts with varying vacancy (CuO-O V ) concentrations and morphological structures. CuO-O V can significantly enhance the selectivity for ethylene (C 2 H 4 ) and multicarbon products (C 2+ ) by reducing the free energy required for the formation of ∗CHO intermediates from ∗CO hydrogenation and lowering the energy barrier for C-C coupling reactions. The CuO(NaOH) catalyst exhibited a maximum Faradaic efficiency of 55.7% for the C 2+ product at -1.36 V vs. RHE. And C 2 H 4 displays a maximum Faradaic efficiency of ∼32.7% at -1.56 V vs. RHE.