Understanding the Structural-Dependent Photocatalytic Antibacterial Activity: a Case Study of Ag Modified BiVO₄

In this work, Ag/BiVO₄ heterostructural photocatalysts were developed in order to reveal exceptional structural-dependent photoinduced charge migration kinetics as well as the underlying photocatalytic antibacterial dynamic process. The structure-dependent interface of BiVO₄ and Ag nanoparticles was successfully constructed to improve the photoinduced interface charge transfer efficiency and interface correlation. DFT calculation indicated that a net charge of about 0.33 e between Ag and tz-BiVO₄ was achieved by extraordinary interface charge transfer, being far larger than that between Ag and ms-BiVO₄. Larger net charge has consequences on mobility of charge carriers of tz-BiVO₄ that can raise the migration and separation of charge carriers for Ag/tz-BiVO₄ heterojunction. Fine interfacial contact between Ag and tz-BiVO₄ led to the optimized photocatalytic performance toward E. coli inactivation, being predominately higher than that of tz-BiVO₄, ms-BiVO₄, and Ag/ms-BiVO₄ catalysts. Besides photocatalytic activity, the thermocatalytic inactivation activity of Ag/tz-BiVO₄ also exhibited a factor of about 7.2 and 3.1 times higher than that of tz-BiVO₄ and Ag/ms-BiVO₄. Trapping and EPR measurements suggested that the structural-dependent photocatalytic activity of Ag/BiVO₄ mainly originated from the pronounced variation of the capability to produce H₂O₂ active species, where the capability of generating H₂O₂ over Ag/tz-BiVO₄ is highly accelerated. Moreover, it cannot be ignored that this study provides an ideal candidate for many aspects, such as environmental and water pollution caused by pathogenic microorganisms and disinfection of medical materials, food packaging, household materials, and public places, etc.