Abstract: The widespread use of antibiotics has inflicted significant environmental damage, prompting global concern and the urgent need for effective remediation strategies. In this study, by designing the structure and interface functionality on the basis of the different work functions, we developed a novel S-Scheme MnIn₂S₄@BiVO₄ heterojunction via electrostatic self-assembly, displaying the heightened photocatalytic performance in the breakdown of tetracycline hydrochloride (TC) upon visible light irradiation. The removal rate of superior MnIn₂S₄@BiVO₄ heterojunction was 1.83 and 3.55 times higher than that of individual components MnIn₂S₄ and BiVO₄, respectively. By offering a substantial contact area between the catalyst and the reaction solution, the heterogeneous interface boosts the activation and degradation of pollutants. Furthermore, the photothermal effect expedites the degradation reaction. Capturing agent experiments and ESR investigations identified •O₂⁻ and •OH as the dominant reactive species driving this degradation process and an analysis of intermediates by HPLC-MS with a notable reduction in the toxicity of the degradation products was conducted to explore a potential degradation pathway for TC. The heightened photocatalytic efficacy of the heterojunction is credited to the S-scheme charge transfer mechanism, which boosts the utilization of charge separation, as evidenced by in-situ XPS and DFT calculations. This study offers novel perspectives on the development of S-scheme heterojunction to improve the photocatalytic degradation of persistent organic pollutants.

Key words: MnIn₂S₄, BiVO₄, Photocatalysis, Tetracycline hydrochloride, S-scheme heterojunction