Bimetallic CuMo@TiO2 activating peroxymonosulfate for micropollutants degradation: Synergy and mechanism

Abstract

Bimetallic catalysts and single metal photo-catalytic products displayed excellent PMS-activated ability for a long time. However, the synergistic mechanism of bimetallic with photo-generated electrons and the mechanism of 1O2 generation and conversion were still obscure. In this work, CuMo@TiO2 was coupled with PMS to confirm the synergistic effect of Cu-Mo bimetallic with photo-generated electrons and this effect on the generation and conversion of ROS. IDM (20 ppm) almost achieved complete degradation in CuMo@TiO2/PMS system within 30 min, and the reaction system remained efficient with the presence of common inorganic anions or over a wide pH range (5.0–8.0). Experimental and analysis demonstrated that Cu-Mo bimetallic provided metal activation sites for PMS activation and those activation sites derived electron transfer enhanced the radical and non-radical pathway. Photo-generated electrons offered a powerful driving force for the redox of Cu-Mo bimetallic. The photo-generated electrons under the solar light and increased electron transfer between Cu-Mo promoted the generation and conversion of active species (.OH, O2·-, SO4·-, SO5·-) to 1O2. This work provides the theoretical and experimental foundation for the further research of bimetallic photo-catalytic systems.