Regulating surface state of WO₃ nanosheets by gamma irradiation for suppressing hydrogen evolution reaction in electrochemical N₂ fixation

Realizing the reduction of N₂ to NH₃ at low temperature and pressure is always the unremitting pursuit of scientists and then electrochemical nitrogen reduction reaction offers an intriguing alternative. Here, we develop a feasible way, gamma irradiation, for constructing defective structure on the surface of WO₃ nanosheets, which is clearly observed at the atomic scale by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). The abundant oxygen vacancies ensure WO₃ nanosheets with a Faradaic efficiency of 23% at -0.3 V vs. RHE. Moreover, we start from the regulation of the surface state to suppress proton availability towards hydrogen evolution reaction (HER) on the active site and thus boost the selectivity of nitrogen reduction.