Constructing synergistic effects of ZnIn2S4_Sv/WO3 heterojunctions with boosted photocatalytic sterilization under visible light irradiation

In this study, the ZnIn₂S₄ photocatalyst was synthesized via a solvothermal method, wherein the concentration of the sulfur precursor was adjusted to incorporate sulfur vacancy structures (ZnIn₂S₄_S_v, ZnCl₂: 0.8 mmol, InCl₃:1.6 mmol, and TAA: 6.4 mmol). Subsequently, the WO₃ was coupled with ZnIn₂S₄_S_v to create a synergistic effect through defect engineering and heterojunction formation. The results indicated that coupling 0.500 mmol WO₃ with ZnIn₂S₄_S_v to form a ZnIn₂S₄_S_v/WO₃ heterojunction resulted in superior specific surface area and reduced charge transfer resistance. This configuration achieved a 99.77 % inactivation efficiency of Escherichia coli (E.coli) in 120 min, and the reaction rate was 2.37- and 7.80-fold higher than those of individual ZnIn₂S₄_S_v and WO₃, respectively. The XPS and ESR experiments confirmed the construction of an S-scheme heterojunction charge-transfer pathway between ZnIn₂S₄_S_v and WO₃, thereby retarding charge recombination and facilitating the generation of reactive oxygen species, which enhanced hydrogen peroxide production and bacterial inactivation performance.