Hydrothermal synthesis of m-BiVO4 and m-BiVO4/BiOBr with various facets and morphologies and their photocatalytic performance under visible light

In this work, the 3D four petaled flower-like, cube-like and rod-like m-BiVO4 samples and four corners star-like m-BiVO4/BiOBr heterojunctions with various exposed (040) facets were successfully prepared by a hydrothermal method. The microstructure and the crystalline structure of as-prepared m-BiVO4 and m-BiVO4/BiOBr heterojunctions influenced by molar ratio of Br:V had been investigated by XRD, SEM, TEM, HRTEM, N2 absorption–desorption, XPS, PL and DRS. In addition, the photocatalytic performance of the prepared m-BiVO4 and m-BiVO4/BiOBr heterojunctions were evaluated by monitoring the degradation of Rhodamine B (RhB) contained wastewater under visible light irradiation. The highest photocatalytic degradation efficiency can be achieved for the m-BiVO4/BiOBr heterojunctions with Br:V molar ratio of 3:1, which was attributed to the predominately exposed (040) facets of m-BiVO4 and high exposing proportion of (001) facets of BiOBr, the highest BET, the lowest Eg and the worst recombination rate of photo-generated electron-hole pairs.