Construction of stable Cu⁺/Cu⁰ interfaces via in situ cyclic voltammetry for CO₂ electrochemical reduction to ethylene under high current density

Electrochemical CO₂ reduction reaction (CO₂RR) coupled with renewable electricity offers a promising strategy to convert CO₂ into value-added chemicals while addressing the challenges of carbon emissions. Although copper-based catalysts have demonstrated promising capability in CO₂-to-hydrocarbon conversion, achieving highly selective and energy-efficient production of C₂₊ products, particularly ethylene (C₂H₄), remains a significant challenge. Herein, we report a novel strategy to construct oxidation-derived copper (ODCu) nanowire catalysts through a combination of electrodeposition, wet-chemical synthesis, and cyclic voltammetry (CV) redox process. During the CV treatment, the catalyst undergoes in situ surface reconstruction, resulting in the formation of abundant Cu⁺/Cu⁰ interfaces. The optimized ODCu nanowire catalyst exhibits remarkable C₂H₄ selectivity with a faradaic efficiency (FE) of 54 % ± 4 % and a partial current density of 154 ± 12 mA·cm⁻² at −1.0 V (vs reversible hydrogen electrode, RHE), demonstrating stable performance for 12 h. Through in situ infrared spectroscopy (FTIR) analysis and density functional theory (DFT) calculations, we reveal that the engineered Cu⁺/Cu⁰ interfaces significantly lower the activation energy barrier for C[sbnd]C coupling, thereby promoting the selective formation of C₂H₄. This work provides new insights into interface engineering for enhanced CO₂RR performance and offers an effective strategy for developing high-performance copper-based electrocatalysts.