Rapid mineralization of indoor acetaldehyde under visible light via phase-modulated MoS2 quantum dots/WO3 photocatalysts

Visible-light-driven photocatalysis offers a sustainable strategy to eliminate indoor volatile organic compounds (VOCs) like acetaldehyde (AA), thereby improving indoor air quality. Although heterojunctions based on MoS 2 quantum dots (MQDs) attract attention for oxidation reactions, MQDs/WO 3 composites for VOC removal remain largely underexplored. In this study, MQDs/WO 3 heterojunctions were constructed by coupling MQDs with monoclinic (m-WO 3 ) and hexagonal (h-WO 3 ) phases to systematically investigate phase-dependent charge transfer, reactive oxygen species (ROS) generation, and AA degradation pathways. Comprehensive characterizations indicated that MQDs incorporation increased oxygen vacancies, promoted ROS generation, and enhanced visible-light absorption. Furthermore, PL and in situ DRIFTS analyses revealed that MQDs/m-WO 3 exhibited superior electron-hole separation and stronger surface reactivity than the h-WO 3 system. DFT calculations confirmed MQDs as the primary adsorption sites for indoor VOCs, with MQDs/m-WO 3 exhibiting stronger AA adsorption. Consequently, the optimized 0.5MQDs/m-WO 3 demonstrated enhanced AA degradation and mineralization under visible light, exhibiting excellent stability under indoor-relevant operating conditions. This work provides profound insights into interface-regulated charge transfer and offers a promising material design strategy for advanced indoor air purification.