Synthesis of Bi4O5Br2 from reorganization of BiOBr and its excellent visible light photocatalytic activity

In this study, a novel visible-light-driven Bi4O5Br2 photocatalyst was successfully synthesized via the structure reorganization of BiOBr at room temperature using NH3 center dot H2O as a structure-controlling agent. The obtained Bi4O5Br2 exhibited outstanding visible light activity and stability compared to BiOBr and P25 for the degradation of resorcinol. The physicochemical properties of Bi4O5Br2 were analyzed and calculated by modern characterization techniques and density functional theory (DFT). The results revealed that the excellent performance could be mainly attributed to the effect of O-richness on the electronic properties of Bi and Br atoms, unique morphology, high visible-light absorption capacity, and prominent oxidation ability of photo-induced holes. Radical trapping experiments demonstrated that h(+) and (OH)-O-center dot radicals were the dominant active species. Moreover, a structure reorganization mechanism was proposed, revealing that ammonia and the water-steeping process both played important roles in the fabrication of Bi4O5Br2. We believe that this facile method could be extended to fabricate other three component Bi-O-Br nanostructure systems and help elucidate the relationship between BiOBr and BixOyBrz.