One-pot hydrothermal preparation of Br-doped BiVO4 with enhanced visible-light photocatalytic activity

In this contribution, Br-doped BiVO4 photocatalysts were successfully obtained by a one-pot hydrothermal method. High resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) were employed to confirm that Br was successfully doped into BiVO4. The separation performance of photo-generated carriers of Br-doped BiVO4 photocatalysts was studied by electrochemical technology and surface photovoltage spectroscopy (SPS). The results show that the existence of an impurity energy level formed by Br doping promotes the separation of photoinduced carriers. Photocatalytic properties of the samples towards degradation of Rhodamine B (RhB) and tetracycline (TC) were assessed under visible light irradiation. The experimental results reveal that photocatalytic performance of Br-doped BiVO4 photocatalysts is higher than that of the reference BiVO4. Under visible light irradiation, the abatement rate constant of RhB and TC over 3% Br-doped BiVO4 is 7 times of that over the reference BiVO4, respectively. The active free radicals were detected by electron spin resonance (ESR) and trapping experiments. The results indicate that superoxide free radical (O2−) and hole (h+) are main active free species, and the 3% Br-doped BiVO4 produces more active free radicals. On account of all the observations, the separation and transfer mechanism of photogenerated charge was proposed. This work provides a useful reference for the preparation of highly efficient Br-doped photocatalytic materials.