Facile synthesis of three-dimensional WO3-x/Bi/BiOCl hierarchical heterostructures with broad spectrum driven photocatalytic activity

To improve the utilization efficiency of solar energy and separation of photogenerated carries, a novel three-dimensional (3D) WO 3-x /Bi/BiOCl hierarchical heterostructures with broad spectrum responsive photocatalytic activity have been fabricated through a facile solvothermal technique. The influences of varying loading of WO 3-x on the physical performances of the as-obtained composites were systematically characterized by X-ray diffraction, scanning electron microscope, transmission electron microscopy , X-ray photoelectron spectroscopy, optical absorbance, photoluminescence and specific surface areas. The WO 3-x /Bi/BiOCl displayed a strong optical absorption from 250 to 2500 nm, and showed the superior photocatalytic performance in degradation of rhodamine B (RhB) than that of individual components. Among the as-prepared samples, the sample S24 with the appropriate content of WO 3-x displayed the best photocatalytic performance, which can photodegrade RhB with the efficiency of 100%, 100% and 96% under the UV light within 8 min, visible light within 3 min and near-infrared light within 120 min exposure, respectively. Furthermore, a plausible mechanism of the RhB degradation on WO 3-x /Bi/BiOCl photocatalysts under the near-infrared light irradiation was proposed according to the photocatalytic activity and radical species trapping experiments.