ZnO/Cu2S PN-junctions with built-in electric field for enhanced CO2 electroreduction

A full stack strategy, including facilitating the capture of CO2 molecules on catalysts, regulating intermediates, and releasing products, is highly needed to break the bottleneck for CO2 electroreduction to CO. The electric field is expected to promote capture of CO2, reduce energy barriers of reaction, and efficiently release CO, boosting the overall CO2 reduction reaction (CO2RR) activities. In this work, ZnO/Cu2S PN-junctions with a built-in electric field were fabricated. Kelvin probe force microscopy measurements confirmed that the presence of the built-in electric field facilitates the adsorption of more CO2 molecules onto the catalyst surface. Furthermore, theoretical calculations and electrochemical testing demonstrated that the built-in electric field lowers the reaction energy barrier and effectively modulates the reaction intermediates, contributing to enhanced catalytic performance. This work provides a full stack strategy to improve CO2RR performance and thinking for gas-fed catalytic reactions.