In situ stabilization of Cu+ for CO2 Electroreduction via Environmental-molecules-induced ZnO1-x shield

Electrochemical CO 2 -to-ethanol conversion is challenged by sluggish C-C coupling kinetics and wide products distribution. Although Cu +  has been demonstrated to enhance multi-carbon (C 2+ ) formation, the stabilization of Cu + under reduction conditions is difficult. Here, we report a hydrogen-ethanol pretreatment strategy to obtain Cu nanoparticles covered by highly dispersed and disordered ZnO 1- x clusters. Ethanol-induced ZnO 1- x redispersion gives rise to abundant Cu + on the subsurface. The optimal catalyst delivers a 73.0% ethanol Faradaic efficiency (FE) and 86.0% total C 2+ FE at −0.9 V, with a 2.3 mmol cm −2  h −1 ethanol formation rate and single-pass ethanol yield of 18.0%. The catalyst also exhibits stability beyond 500 h, attributed to the stabilization of Cu + by the ZnO 1- x shield that requires a high energy barrier for lattice oxygen removal. In situ X-ray spectroscopy and calculations reveal a volcano relationship between Cu + ratio in Cu species and ethanol FE. Optimal Cu + density not only facilitates *OC-COH coupling but also optimizes the adsorption energy of *CH 2 CH 2 O on catalyst for ethanol electrosynthesis.