Promotion of Electrochemical Reduction of CO2 over Cu2O-Cu (111) Interface Assisted by Oxygen Vacancies

Abstract

With the rapid development of industry, large-scale fossil energy consumption leads to the increase of atmospheric CO2 concentration and the resultant deteriorating global warming. The electrochemical reduction of CO2 (ERCO2) technology is a potential strategy to achieve the CO2 emissions reduction and to realize carbon recycling. However, the lack of high product selective, active and stable catalysts is one of the remaining challenges for the industrial applications of ERCO2. Herein, an electrochemical oxidation-reduction reconstruction method is developed to reconstruct the copper network without extra Cu salt addition obtaining Cu2O-Cu (111) catalysts with nanoporous structures for improving the selectivity and activity of CH4 and C2H4 product. The oxidation-reduction reconstruction derived catalyst achieves improved faradaic efficiency of 56.63% for CH4 product and a partial current density of 41.6 mA cm-2 at -1.38 V (vs. RHE). The selectivity and activity toward C2H4 are also improved. The catalytic superiority originates from synergistic interplay between the Cu₂O-Cu heterogeneous interface and high electrochemical active surface area. Additionally, the presence of abundant oxygen vacancies at the Cu2O-Cu interface accelerate the electron transfer process and promote the high selectivity and activity toward CO2-to-CH4. This study paves a new way for enhancing the selectivity and activity of CO2 electrocatalytic conversion to CH4.