Suppressing hydrogen evolution for high selective CO2 reduction through surface-reconstructed heterojunction photocatalyst

Abstract The utilization of solar energy for CO2 reduction reaction (CO2RR) into valuable hydrocarbons offers attractive solution towards low-carbon future, but their performance is affected by the competing hydrogen evolution reaction (HER) that occurs simultaneously. Herein, we proposed maximizing interface integration and surface reconstructing engineer strategy to improve the CO2RR activity and selectivity of heterojunction photocatalyst. A surface-reconstructed ZnO/CuOx catalysts are uniformly anchored on the porous carbon nanosheet arrays that are supported by carbon nanofibers (ZnO/CuOx-C CNFs). Downsizing ZnO/CuOx maximizes the interface integration of components to promote electron-hole pairs separation and increase surface active site density. Moreover, the surface reconstruction (the formation of the hydroxyl groups on ZnO via facile light irradiation) promotes the kinetic of CO2RR to CH4 and oxygen evolution reaction (OER), while depressing the competing HER and CO generation. All these advantages contribute to the excellent catalytic performance: a high CH4 generation rate of 241.6 μmol h−1 g−1 with the selectivity of ∼96 % for ZnO/CuOx-C CNFs under full light irradiation. The insight into the modification of photocatalyst structure and mechanism investigation pave the way for a new design strategy to advance solar photocatalytic technology for CO2 reduction.