Unraveling reactive oxygen species-dependent toluene mineralization routes via construction of TixSn1−xO2 infinite solid solution photocatalysts

Intermediates seriously affect the reaction process and rate in terms of kinetics. However, there are few studies on the effect of reactive oxygen species on intermediates of toluene mineralization. Herein, SnO2 and TixSn1−xO2 infinite solid solution photocatalysts are prepared and the mineralization ability of Ti0.1Sn0.9O2 is 2.7 times that of SnO2. Introduction of Ti shifts the conduction band position upward, providing thermodynamic possibility for superoxide radicals formation. The sole hydroxyl radicals over SnO2 lead to the generation of benzyl alcohol; while synergetic hydroxyl radicals and superoxide radicals result in benzoic acid existed in solid solution catalysts. Theoretical calculation confirms that benzoic acid has lower ring opening barrier, thereby improving toluene mineralization ability over TixSn1−xO2. The synergetic roles of Ti and Sn in adsorption and activation of water and toluene moleculars are also proposed. This work provides new insights into reactive oxygen radicals regulation to alter intermediates and ease toluene removal.