First hydrothermal synthesis of Bi5O7Br and its photocatalytic properties for molecular oxygen activation and RhB degradation

Comparing with BiOX (X = Cl, Br, I), BixOyXz as the newest bismuth-based photocatalysts have more appropriate conduction band position. And so, they can be used to active molecular oxygen. In this paper, Bi5O7Br, a new BixOyXz semiconductor photocatalyst was firstly synthesized by via hydromel method. It was characterized by X-ray diffraction (XRD), UV–visible diffused reflectance spectra (DRS), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM) and the corresponding selected-area electron diffraction (SAED) pattern. It can be found that the crystal structure and morphology are same with Bi5O7I. The size of a single rod is about 2 μm in width and 50 μm in length. As-synthesized Bi5O7Br can effectively activate molecular oxygen to generate superoxide radical (O2•−) and hydroxyl radical (•OH) under UV–vis light irradiation. And it also showed high photocatalytic activity than BiOBr for the degradation of dyes. Thus, it can be seen, the appearance of Bi5O7Br photocatalysis enriched the bismuth-rich strategy of Bi-O-X photocatalysts.