Sulfate-mediated reactive oxygen species for efficient photocatalytic nitrogen fixation over TiO2

Abstract

Direct photocatalytic N₂ fixation under mild conditions (compared to the harsh conditions of the Haber–Bosch process) is hindered by NN inertness and lack of controllable activation. Here, a sulfate-modified TiO₂ catalyst (S-TiO₂) achieves an NH₃ production rate of 217.24 µmol h⁻¹ g⁻¹ at 200 °C in simulated air. The mechanism follows an “oxidation-first, reduction-later” pathway: sulfate-derived ROS oxidize N₂ to NO_x intermediates, which are then hydrogenated to NH₃ (confirmed by in situ FTIR and MS). This work provides new insights into solar-driven N₂ fixation.