Facile hydrothermal synthesis and photocatalytic activity of bismuth tungstate hierarchical hollow spheres with an ultrahigh surface area.

Bismuth tungstate has attracted great attention as a new photocatalyst working under visible irradiation. In this paper, we demonstrate a facile hydrothermal route for controllable synthesis of novel Bi(2)WO(6) hierarchical hollow spheres with an ultrahigh specific surface area in the presence of poly(vinyl pyrrolidone) at a proper C(2)H(5)OH/CH(3)COOH/H(2)O volume ratio. The obtained products are systematically studied by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer-Emmett-Teller (BET) and UV-vis absorption spectroscopy. It is shown that the Bi(2)WO(6) hollow spheres are constructed of numerous nanoplates while the nanoplates consist of a great deal of nanoparticles. UV-vis spectrum is used to estimate the band gap energy (about 2.90 eV) of the Bi(2)WO(6) hollow spheres. The ultrahigh BET specific surface area of ca. 45.0 m(2) g(-1) is displayed for the Bi(2)WO(6) hierarchical hollow spheres, which is much higher than that for all the previously reported Bi(2)WO(6) products. The Bi(2)WO(6) hierarchical hollow spheres are displayed to possess superior photocatalytic activity in the photodegradation of rhodamine B (RhB) under visible light irradiation over other morphological products.