Enhanced Photocatalytic Activity of BiOBr/ZnO Heterojunction Semiconductors Prepared by Facile Hydrothermal Method

Hexagonal wurtzite pure ZnO and BiOBr-ZnO composites were synthesized by facile hydrothermal method. The amount of BiOBr as dopant was adjusted from 5 wt.% to 75 wt.%, and correspondingly the morphologies and crystal structures of the as-prepared composites were measured and discussed. Specifically, according to XRD patterns and SEM images, the main crystalline structure of ZnO was not destroyed after doping, but growth of ZnO crystals was inhibited by doping BiOBr. Meanwhile, the optical properties of the composites were measured by the diffuse reflectance spectra (DRS). The band gap of composites was also calculated using the classical Tauc equation and it was found to be around 3.0 eV. In the test of photocatalytic activation, the ZnO-BiOBr photocatalysts exhibited high photocatalytic efficiencies in the degradation of Rhodamine B (RhB) under visible-light irradiation. It was ascribed to not only the small size of crystalline, but also the reduction in the recombination rate of the photogenerated carriers for the enhancement effect of p-n heterojunction. This work sheds light on improving the photocatalytic performance by establishing the heterojunction and contributes to the development of a commercially competitive photocatalyst