The effect of Bi content on the photocatalytic performance of bismuth oxybromides

BiOBr, Bi3O4Br and Bi4O5Br2 were prepared by hydrothermal and solvothermal methods. Their structural composition, surface morphology, chemical states and optical properties were characterized by XRD, SEM, XPS and UV-vis. The band structure and density of states of the photocatalysts were calculated by density functional theory (DFT). The photocatalytic activity was evaluated by degradation of RhB. The results show that band gap and the position of conduction band is affected by Bi content. The Bi4O5Br2 photocatalyst could completely degrade RhB in 50 min. Radical-trapping experiments proved that ·O– 2 was the main active species in photocatalytic degradation of RhB.