Interface engineering and oxygen vacancies derived from plasma-treated Cu2O synergistically enhancing electrocatalytic CO2-to-C2+ conversion

Abstract

Electrocatalytic CO₂ reduction (ECR) into value-added chemicals and fuels helps tackle the challenges of the energy crisis and global warming. However, this strategy relies heavily on the rational design of catalysts with high selectivity and activity towards C₂₊ products. Herein, we introduce a dual-engineering strategy using plasma-treated Cu₂O to synergistically enhance the material's catalytic performance for CO₂-to-C₂₊ conversion. We demonstrate that well-controlled plasma reduction treatment in an Ar/H₂ atmosphere can yield stable Cu₂O–Cu catalysts (Cu₂O–Ar/H₂) with Cu⁰/Cu⁺ interfaces, abundant grain boundaries, and a high density of oxygen vacancies. Cu₂O–Ar/H₂ delivers an impressive 81.2% faradaic efficiency for C₂₊ products at an industrial current density of 100 mA cm⁻². Performance comparisons show that plasma pre-reduction treatment samples outperform the in situ reduced Cu₂O sample during ECR. Theoretical calculations reveal that the well-defined Cu⁰/Cu⁺ interfaces optimize intermediate adsorption and the oxygen vacancies provide multiple active sites for C–C coupling. This work establishes a correlation between plasma treatment-generated active sites and high C₂₊ product selectivity. Our work also demonstrates that this facile, scalable, standardized and controllable material preparation method can effectively promote the large-scale application of high-activity ECR catalysts.