Preparation and modification of hierarchical nanostructured Bi2WO6 with high visible light-induced photocatalytic activity

Hierarchical nanostructured Bi2WO6 micro-clews were synthesized by a solvothermal process with mixed solvents and formaldehyde. The hierarchical Bi2WO6 micro-clews, with an average diameter of ca. 1.0 mu m, consisted of nano-sheets assembled in a special fashion and the formation process mainly went through an Ostwald ripening-anisotropic growth and self-assembling process. The Bi2WO6 micro-clews were further modified by Bi2O3 to fabricate heterojunction photocatalysts, where Bi2O3 nanoparticles were uniformly assembled on the surface of Bi2WO6 nano-sheets. Compared with pure Bi2WO6 and Bi2O3, the composite photocatalyst exhibits higher photocatalytic activity for the degradation of rhodamine B under visible light. On the basis of characterization by x-ray diffraction, photoluminescence and UV-vis diffuse reflectance spectroscopies, a mechanism was proposed to account for the enhanced photocatalytic activity of the Bi2O3/Bi2WO6 heterojunction.