Effect of nano-Ag proportion on the structure of Ag– TiO2–Bi2WO6 photocatalyst and its antibacterial property on Escherichia coli

In this study, TiO2–Bi2WO6 (TB) heterojunctions were synthesized by solvothermal method, nano-Ag was reduced by γ-ray irradiation, and a series of Ag–TiO2–Bi2WO6 (ATB) composite photocatalysts with different nano-Ag usage were constructed by chemical deposition and freeze-dried. The microstructure, crystalline phase composition, chemical composition, and light absorption properties of ATB were characterized, and its photocatalytic bacterial inhibition performance was analyzed against Escherichia coli. The results showed that the proportion of nano-Ag significantly improved the photocatalytic inhibition performance of ATB against E. coli, and the highest inhibition rate of ATB against E. coli (52.5%) was achieved when the Ag proportion was 15%, which was 2.5 times higher than that of TB. The improved photocatalytic inhibition performance of ATB was attributed to the combination of the interlaced heterostructure, SPR effect, and Schottky barriers, which narrowed the forbidden bandwidth, promoted the separation of electron-hole pairs, and generated a large number of reactive radicals such as h+, •O2-, and •OH under visible light. Influenced by this, the microbial cell structure was broken and inducted into the E. coli apoptosis. The results provided a novel photocatalyst in photocatalytic antibacterial research. TiO2–Bi2WO6 was synthesized by solvothermal method, nano-Ag was reduced by γ-ray irradiation, Ag–TiO2–Bi2WO6 composite photocatalysts with different nano-Ag additions were constructed by chemical deposition and freeze-drying method, and their photocatalytic inhibition performance was evaluated under visible light with Escherichia coli as the target bacteria. [Display omitted] •Ag/TiO2/Bi2WO6 were synthesized using the solvothermal method and the γ-ray irradiation reduction method.•Ag/TiO2/Bi2WO6 exhibited excellent visible light photocatalytic inhibition performance against Escherichia coli.•The high photocatalytic activity is due to the heterojunction structure, Schottky barrier and LSPR effect.