Self-assembled 3D hierarchical clew-like Bi2WO6 microspheres: Synthesis, photo-induced charges transfer properties, and photocatalytic activities

Three-dimensional (3D) hierarchical clew-like microspheres with small size of bismuth tungstate (Bi2WO6) were successfully synthesized by a simple hydrothermal route at a proper volume ratio (1 : 1) of H2O/EG mixed solution. It has been found that ethylene glycol (EG) plays important roles in the formation of the clew-like structure. Bi2WO6 with different morphologies could be obtained by simply adjusting the volume ratio of the H2O/EG in the mixed solution. The kinetic features of photo-induced charges transfer properties of samples have been discussed by surface photovoltage spectrum (SPS) and transient photovoltage (TPV) techniques in detail. The Bi2WO6 with hierarchical clew-like structure possessed the highest efficiency of electron-hole separation and the lowest recombination rate of photoinduced charges, resulting in the highest photocatalytic activity for the degradation of Orange-II under the visible light (lambda > 420 nm) illumination. The information provided here is thought to be beneficial for engineering high efficient photocatalysts.