Efficient electrochemical reduction of carbon dioxide into ethylene boosted by copper vacancies on stepped cuprous oxide

Electrochemical carbon dioxide (CO2) reduction powered by renewable energy source is a promising strategy for the sustainable carbon cycle, while the selectivity toward C2+ products is still a great challenge. Herein, a novel stepped cuprous oxide catalyst with abundant Cu vacancies (Cu-v-Cu2O catalyst) is developed to enhance the selectivity and efficiency of CO2 conversion toward C-2 products. This catalyst exhibits high C2H4 partial current density and production rate at a low overpotential benefiting from the stepped surface and the modified electronic structure by Cu vacancies. Furthermore, density functional theory calculations demonstrate that the Cu vacancy-enriched Cu2O surface ensures strong adsorption to *COH but weak affinities to *CO and *CH2 intermediates, which promotes CO2 electroreduction to C2H4 products. The enhanced selectivity of C2H4, accompanied with the Cu vacancies and Cu+ species, can remain stable during the long-term test. This study will provide guidance on designing efficient electrocatalysts for CO2 reduction towards hydrocarbon products.