Microdroplet induced catalyst surface fields boost hydroxyl radical generation and its application

Photocatalysis is a promising strategy for environmental remediation but is commonly limited by inefficient charge separation and slow interfacial reaction kinetics. Herein, an aerosolized microdroplet-coupled semiconductor photocatalytic system is developed to enhance photocatalytic performance through interfacial microenvironment regulation. Dispersing TiO₂ nanoparticles into aerosolized microdroplets enables synergistic coupling between the strong built-in electric field at the gas-liquid interface and the localized interfacial electric field at the semiconductor-water interface, which significantly promotes photogenerated charge separation and hydroxyl radical generation. The microdroplet-assisted system achieved a •OH generation rate of 0.31 min⁻¹ within 60 min and a methylene blue degradation rate of 0.16 min⁻¹ within 20 min, markedly outperforming the bulk-phase photocatalytic system (0.17 and 0.11 min⁻¹, respectively). The enhancement strategy was further validated using multiple semiconductor photocatalysts, including ZnO, CuO, Fe₂O₃, and ZrO₂, all of which exhibited improved photocatalytic activity under microdroplet-assisted conditions. In addition, efficient pollutant degradation was achieved in real river water samples, demonstrating good system stability and practical applicability. This work highlights microdroplet-induced interfacial electric field coupling as an effective approach for boosting photocatalytic efficiency, offering new insights for the design of advanced photocatalytic systems for environmental applications.