Facile preparation of flower-like Bi2WO6/CdS heterostructured photocatalyst with enhanced visible-light-driven photocatalytic activity for Cr(VI) reduction

Visible-light-driven CdS loaded flower-like Bi2WO6 (Bi2WO6/CdS) heterostructured photocatalyst with surface-enrich CdS nanoparticles were prepared successfully by using a facile two-step method. The as-prepared photocatalyst was characterized by X-ray diffraction, scanning electron microscopy, and UV-Vis diffuse reflectance spectrum. The band gaps of the samples were estimated based on diffuse reflectance spectrum results. The as-prepared Bi2WO6/CdS heterostructured photocatalyst was used as catalysts in reduction of Cr(VI) to Cr(III) under visible light irradiation, and enhanced photocatalytic activities were observed as compared to pure flower-like Bi2WO6 and CdS nanoparticles. The origin of the excellent performance of the catalyst as well as the mechanism of photoreduction was discussed. Effective electron-hole separation and variation of band gap due to the formation of type II heterostructure is believed to be responsible to the much improved reaction rate. Flower-like Bi2WO6/CdS heterostructures was used to photoreduce toxic Cr(VI) to Cr(III) under visible light irradiation. 99% reduction of Cr(VI) could be reached within 10 min. It is found that the heterogenization favors the facilitated interfacial charge transfer and inhibited electron-hole recombination. [GRAPHICS]