Cu2+1O/CuOx heterostructures promote the electrosynthesis of C2+ products from CO2

Manipulating the oxidation state of Cu catalysts can significantly affect the selectivity and activity of electrocatalytic carbon dioxide reduction (CO2RR). However, the thermodynamically favorable cathodic reduction to metallic states typically leads to catalytic deactivation. Herein, a defect construction strategy is employed to prepare crystalline/amorphous Cu2+1O/CuOx heterostructures (c/a-CuOx) with abundant Cu0 and Cuδ+ (0 < δ< 1) sites for CO2RR. The C2+ Faradaic efficiency of the heterostructured Cu catalyst is up to 81.3%, with partial current densities of 406.7 mA·cm−2. Significantly, real-time monitoring of the Cu oxidation state evolution by in-situ Raman spectroscopy confirms the stability of Cuδ+ species under long-term high current density operation. Density functional theory (DFT) calculations further reveal that the adjacent Cu0 and Cuδ+ sites in heterostructured c/a-CuOx can efficiently reduce the energy barrier of CO coupling for C2+ products.