Hydrothermal preparation of 3D flower-like BiPO/BiWO microsphere with enhanced visible-light photocatalytic activity.

A novel 3D flower-like BiPO/BiWO photocatalyst was prepared using hydrothermal method. The crystal structure, surface morphologies and optical properties of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) and Ultraviolet-visible diffuse reflectance spectrum (UV-vis DRS). The photocatalytic activity of the BiPO/BiWO composites was evaluated by using rhodamine B (RhB) as a target organic pollutant under visible light irradiation. The composite with the content of 15% BiPO exhibited the highest photocatalytic property with the 92% removal rate of RhB within 100 min under visible light irradiation, which ascribed to the fast separation efficiency of photo-induced charge carriers, according with the results of photoluminescence (PL), photocurrent (PC) and electrochemical impedance spectroscopy (EIS). Also, it showed superior stability after three times of recycling. Eventually, the possible photocatalytic mechanism of BiPO/BiWO composite was proposed according to the energy band structure and the radical-trapping experiment.