S-scheme enhanced photocatalysis on titanium oxide clusters functionalized with soluble perylene diimides

Abstract

Fabricating S-scheme photocatalysts to optimize their ability of using sunlight has gained great attention in environmental remediation. Herein, we designed a soluble hybrid, titanium oxide cluster–perylene diimide–polyhedral oligomeric silsesquioxane (TOC–PDI–POSS). Through π–π stacking interaction with the most commonly applied graphitic carbon nitride (g-C₃N₄), a new S-scheme heterostructure was successfully constructed. The combination of the near full visible light responsive TOC–PDI–POSS and g-C₃N₄ enhanced the utilization of sunlight to achieve highly efficient charge-carrier separation. More importantly, the photo-Fenton reaction can be achieved without an extra oxidant. Owing to the enhanced oxidation capacity of holes, the obtained TOC–PDI–POSS/g-C₃N₄ heterostructure displayed efficient photocatalytic degradation for phenol under an air atmosphere and the reaction rate constant reaches 5.6 h⁻¹ in five cycles under simulated sunlight.