Visible-Light-Driven Catalytic Disinfection of Staphylococcus aureus Using Sandwich Structure g-C3N4/ZnO/Stellerite Hybrid Photocatalyst

A novel g-C₃N₄/ZnO/stellerite (CNZOS) hybrid photocatalyst, which was synthesized by coupled hydro thermal-thermal polymerization processing, was applied as an efficient visible-light-driven photocatalyst against Staphylococcus aureus. The optimum synthesized hybrid photocatalyst showed a sandwich structure morphology with layered g-C₃N₄ (doping amount: 40 wt%) deposited onto micron-sized ZnO/stellerite particles (ZnO average diameter: ~18 nm). It had a narrowing band gap (2.48 eV) and enlarged specific surface area (23.05 m²/g). The semiconductor heterojunction effect from ZnO to g-C₃N₄ leads to intensive absorption of the visible region and rapid separation of the photogenerated electron-hole pairs. In this study, CNZOS showed better photocatalytic disinfection efficiency than g-C₃N₄/ZnO powders. The disinfection mechanism was systematically investigated by scavenger-quenching methods, indicating the important role of H₂O₂ in both systems. Furthermore, h⁺ was demonstrated as another important radical in oxidative inactivation of the CNZOS system. In respect of the great disinfection efficiency and practicability, the CNZOS heterojunction photocatalyst may offer many disinfection applications.