Oxygen vacancy enhanced photocatalytic performance towards marine microorganisms inactivation over Ag/Bi₂O₃

In this study, Bi₂O₃-OV with different concentrations of oxygen vacancies was prepared by reduction method, Ag NPs were loaded onto pure Bi₂O₃ and Bi₂O₃-OV by photodeposition. The effect of different electronic structures of the carrier on the performance and reaction mechanism of the Ag-loaded catalysts was also emphasized. The results showed that the sterilization rate of pure Bi₂O₃ was only 49.56% after half an hour of light exposure, the sterilization rate of Ag/Bi₂O₃ composite catalyst without vacancies was as high as 76.17%, and the sterilization efficiency of Ag/Bi₂O₃ composite catalyst with oxygen vacancies was up to 98.21%. The presence of vacancies caused the Ag/Bi₂O₃ composite catalyst to produce 15.13 μM H₂O₂, which was nearly twice as much as that of Bi₂O₃/0.5Ag, and was the main active species for sterilization, while the main active species for sterilization of the Ag/Bi₂O₃ composite catalyst without vacancies was the hydroxyl radicals generated from the valence band. This work not only enriches the study of the mechanism of inactivation of marine microorganisms by silver-loaded photocatalysts, but also provides a theoretical basis for the advancement of marine pollution treatment technology.