Facile synthesis of Ag/AgCl/BiOCl ternary nanocomposites for photocatalytic inactivation of S. aureus under visible light

Abstract

Ag/AgCl/BiOCl nanosheets were synthesized by a situ ion exchange between BiOCl nanosheets and AgNO₃ solution followed by visible light reduction at room temperature. The obtained sample was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscope (TEM). Benefitting from the fact that Ag nanoparticles can respond to visible light and the ternary composite can effectively separate the photo-generated electrons and holes, the Ag/AgCl/BiOCl nanocomposite displayed enhanced visible-light-driven (VLD) photocatalytic inactivation of S. aureus, which was superior to BiOCl, Ag/BiOCl, AgCl/BiOCl, Ag/AgCl and Ag/AgCl/TiO₂. Moreover, the mechanism of photocatalytic bacterial inactivation was investigated by using different scavengers and a simple partition system which is able to separate the catalyst and bacteria. It was found that the direct contact between Ag/AgCl/BiOCl nanocomposites and bacterial cells was unnecessary for the photocatalytic disinfection, and the diffusing H₂O₂ generated from holes reduction via a multi-electron pathway plays an important role in the photocatalytic disinfection. Finally, the photocatalytic destruction of the bacterial cells was directly observed by atomic force microscopy (AFM). This work provides a potential effective VLD photocatalyst to disinfect S. aureus cells.