Ag doped Bi3O4Br with active (002) facet for the promotion of bisphenol A photodegradation: Mechanism, pathways and DFT calculation

Bi3O4Br with different facet has different activity. In this paper, the noble metal Ag was designed to dope on the (002) facet (surface) or (020) facet (edge) of Bi3O4Br by simple solvothermal methods. The morphology, band structure and crystal form of the prepared composites were systematically studied and discussed. The photocatalytic efficiencies of the materials were tested through bisphenol A degradation under irradiation of simulated sunlight. Comparatively, the rate constant of Ag/Bi3O4Br (002) is 1.81 and 2.84 times higher than that of Ag/Bi3O4Br (020) and Bi3O4Br, respectively, indicating that: (1) the (002) facet of Bi3O4Br has the distinct activity; (2) the construction of metal particle doping in the (002) crystal plane can effectively improve the carrier transport rate. In order to further explore the photocatalytic pathways of bisphenol A, the intermediates and the free radicals were determined, which was also verified by the density functional theory calculation. The degradation mechanism was put forward to explain the separation and migration behavior of photogenerated charge pairs and the distinguished performance of Ag/Bi3O4Br (002).