Simultaneously tuning oxygen reduction pathway and charge transfer dynamics toward sacrificial agent-free photocatalytic H2O2 production for in-situ water disinfection

Abstract

Developing effective dual-function photocatalyst for sacrificial agent-free superior H2O2 production and in-situ water disinfection is a great challenge. Herein, defect engineering and interfacial chemical coupling dual-strategy is established to fabricate Sv-MoS2/BN heterojunction. The superior photocatalytic activity of Sv-MoS2/BN ascribes to the synergistic advantages of optimized electronic structure, improved oxygen adsorption property and charge separation efficiency. The optimal Sv-MoS2/BN-5 exhibits excellent H2O2 generation rate of 428.17 μmol h−1 g−1 and complete in-situ E. coli disinfection (7.78-log). Density functional theory calculation and rotating disk electrode (RDE) tests revealing that the existence of sulfur vacancies can regulate the interfacial barrier by reducing the work function, which switch oxygen-reduction route from two-step single-electron to one-step two-electron. The switch of oxygen reduction route remarkably promote the generation of the primary bactericidal species, H2O2, leading to significantly improved in situ photocatalytic disinfection efficiency. Moreover, the synthesized material still maintains high catalytic activity in a wide pH range and actual water. This research provides insights by modulating interfacial oxygen reduction for sacrificial agent-free H2O2 generation and in-situ water disinfection.