Promotion of electrochemical reduction of CO2 over the Cu2O–Cu(111) interface assisted by oxygen vacancies

Abstract

With the rapid development of industry, large-scale fossil energy consumption leads to an increase of the atmospheric CO₂ concentration and the resultant deteriorating global warming. The electrochemical reduction of CO₂ (ERCO₂) technology is a potential strategy to achieve the CO₂ emission reduction and to realize carbon recycling. However, the lack of high 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 for CH₄ and C₂H₄ products. The oxidation–reduction reconstruction derived catalyst exhibits an improved Faradaic efficiency of 56.63% for the 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 the high electrochemically active surface area. Additionally, the presence of abundant oxygen vacancies at the Cu₂O–Cu interface accelerates the electron transfer process and promotes high selectivity and activity toward CO₂-to-CH₄ conversion. This study paves a new way for enhancing the selectivity and activity for electrocatalytic conversion of CO₂ to CH₄.