Ag@Bi5O7I nanoparticles deposited on Bi(OH)3 nanosheets for boosting photocatalytic antibacterial activity under visible light irradiation

A novel Ag@Bi5O7I/Bi(OH)3 (AB) heterojunction was prepared and the enhanced photocatalytic antibacterial activity against Escherichia coli (E. coli) under visible light excitation was exhibited. 3 %AB (containing 3 wt% of Ag) presented best photocatalytic performance, and all of E. coli cells were inactivated within 5 min under natural solar light irradiation. The photocatalytic antibacterial mechanism of AB heterojunction was corrobo-rated by SEM, live/dead cell staining and SDS-PAGE assay. The destruction of the cell membrane, the leakage of the intracellular protein and the decomposition of the protein were considered as the events occurred in the antibacterial process. The radical capture experiment confirmed that center dot O2- and e- played the dominant role in the destruction of the cell membrane and the decomposition of the protein. The improvement of the photocatalytic activity can be mainly ascribe to the construction of heterojunction, SPR effect resulted from Ag deposition, enhanced visible light absorption and more surface oxygen vacancies. These factors are advantageous to the generation of the photogenerated electrons and holes, and improve the spatial separation efficiency of the photogenerated charge. This study presented a promising Ag@Bi5O7I/Bi(OH)3 heterojunction as the photo-catalyst for the potential application in the treatment of the bacterial contamination.