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.