Facilitating electroreduction CO2-to-C2H4 over doped CuO nanospheres assisted by nitrogen species and oxygen vacancies

Electrocatalytic reduction is a promising strategy for CO2 utilization, while the conversion of CO2 to C2 products usually suffers from the low selectivity. Herein, we report several high-performance Cu-OCN catalysts for electroreduction CO2-to-C2H4, which are prepared through the in-situ calcination of nanocube Cu2O and urea. The highest C2H4 faradaic efficiency from Cu-OCN-10 reaches 55.97%, much higher than that from the pristine CuO counterpart (38.31%), with a partial current density of -12.83 mA cm-2. Catalyst characterizations and firstprinciples density functional theory calculations reveal that the superior performance of CuO-OCN is attributed to the introduced nitrogen (N) species and oxygen (O)-vacancies. With the assistance of N species and Ovacancies, the adsorption of CO2 on Cu-OCN-10 is thermodynamically favorable with the absorption energy of -0.69 eV. Meanwhile, the activation of CO2 is promoted and the generated *CO intermediate on Cu-OCN-10 is stable, whose release needs to overcome an energy of 2.26 eV, thereby enhancing the C-C coupling to produce C2H4. In general, the synergistic effects of N species and O-vacancies in Cu-OCN catalysts facilitate CO2 electroreduction to C2H4.