Controllable synthesis and photocatalytic activity of spherical, flower-like and nanofibrous bismuth tungstates

Highly crystalline Bi2WO6 particles with high visible light photocatalytic activity were controllably synthesized via a facile hydrothermal process. The phase structures and morphologies were measured by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). XRD patterns demonstrated that the as-prepared Bi2WO6 samples were orthorhombic cell. FESEM showed that Bi2WO6 crystals with distinctive morphologies could be selectively obtained by adjusting the reaction parameters of the hydrothermal process. The formation mechanisms of these distinctive structures were then discussed based on the morphologies analysis of the samples prepared at different conditions. The flower-like Bi2WO6 nanosturcture showed higher photocatalytic activity than that of nanofibrous and spherical Bi2WO6 under visible light irradiation (λ > 420 nm). The reason for the difference in the photocatalytic activities for the three representative samples was systematically studied based on their shape, size and specific surface area.