Stabilizing intermediates and optimizing reaction processes with N doping in Cu2O for enhanced CO2 electroreduction

Appropriate adsorption strength and modes of intermediates on catalysts and the reaction kinetic energy barrier directly determine the selectivity and productivity of final products during CO2 electroreduction. This work systematically reveals the mechanisms for enhanced CO2 electroreduction on nitrogen-doped Cu2O (N-Cu2O) catalyst by in-situ surface enhanced Raman spectroscopy (SERS) and theoretical calculation. The introduction of N into Cu2O can significantly enhance the CO2 adsorption capacity, binding strength of key intermediates and increase the local pH value, resulting in two-fold enhancement of CO and C2H4 production as compared to bare Cu2O. Meanwhile, the protonation step is promoted, making the formation of COOH· quickly and earlier. Therefore, the adsorbed CO2·- intermediate formation is produced more rapidly, and the rate-determining step is transferred, continually facilitating the electroreduction of CO2. This study is inspiring in designing high-performance electrocatalysts for CO2 reduction.