Construction of a novel double S-scheme structure WO3/g-C3N4/BiOI: Enhanced photocatalytic performance for antibacterial activity.

The synthesized WO 3 /g-C 3 N 4 /BiOI photocatalyst followed a double S-scheme transfer process. The active species in the photocatalytic antibacterial process were h+, e−, OH and O2− under LED light. The double S-scheme structure promotes the separation efficiency of electron-hole pairs and increases the redox capacity of the heterojunction, which further improves the antibacterial performance for E. coli and S. aureus. [Display omitted] • Novel double S-scheme WO 3 /g-C 3 N 4 /BiOI photocatalyst was synthesized. • WO 3 /g-C 3 N 4 /BiOI can remove E. coli in 12 min and S. aureus in 20 min. • The active species are h+, e−, OH and O 2 −. • Double S-scheme promotes the electrons and holes separation. • Double S- scheme increases the redox capacity of the heterojunction. In recent years, the threat to human health from bacteria in wastewater has attracted attention, and photocatalytic technology has emerged as a promising strategy for inactivating bacteria in water. Therefore, it is of great research value to develop a novel high-efficiency photocatalytic system with the visible light response. We successfully designed a double S-scheme heterojunction composite WO 3 /g-C 3 N 4 /BiOI (WCB) in this paper. The preparation of WCB composites was demonstrated by a series of characterizations, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The antibacterial effects of photocatalysts against representative Gram-negative strain Escherichia coli (E. coli) and Gram-positive strain Staphylococcus aureus (S. aureus) were tested under LED light irradiation. The novel photocatalyst presented excellent antibacterial properties, inactivating E. coli in 12 min and S. aureus in 20 min. The bacterial cell inactivation process was studied by scanning electron microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM). Active species capture experiments show that the active species present in the WCB composites in the process of inactivating bacteria are h+, e−, OH and O 2 −. In conclusion, the synthesized double S-scheme WCB photocatalyst exhibits remarkable photocatalytic antibacterial activity under LED light and has broad prospects for practical application in water antibacterial treatment. [ABSTRACT FROM AUTHOR]