One-Step Hydrothermal Preparation and Performance of BiOBr/BiPO4 p-n Heterojunction Photocatalyst

BiOBr/BiPO4 p-n heterojunction composite photocatalyst was successfully prepared by one-step hydrothermal method. The physical properties of the samples were characterized by X-ray powder diffraction (X RD), transmission electron microscope (TEM), scanning electron microscope (SEM), N, adsorption-desorption isotherm, X-ray photoelectron spectroscopy (XPS) and UV-Vis diffuse reflection spectrum (UV-Vis DRS). The photocatalytic activity of the sample was evaluated by degradation of rhodamine B under visible light irradiation (lambda > 420 nm), and the effect of BiPO4 content on the photocatalytic activity of the prepared materials was investigated. The main active species in the photocatalytic reaction were determined by capturing experiment, and the photocatalytic mechanism was proposed. The results showed that the optimum molar content of BiPO 4 was 10%, and the optimal catalyst showed the best photocatalytic activity with the reaction rate constant of 0.14 min(-1), which was about 3.7 times that of pure BiOBr. And it also exhibited amostly unchanged photocatalytic activity after three cycling experiments. The improvement of catalytic activity is mainly due to the formation of BiPO4/BiOBr hetemjunction, which improves the separation efficiency of photo-generated carriers. In addition, the enhanced adsorption capacity of pollutants promotes the improvement of catalytic activity. The hole and superoxide radical are the main active species in the photocatalytic process, and the order of the role of the three species is hole > superoxide radical > hydroxyl radical.