Efficient Methylene Blue Removal over Hydrothermally Synthesized Starlike BiVO4

Nanoplate-stacked starlike BiVO4 products have been successfully synthesized by a hydrothermal method, where a water/ethanol mixture was the solvent and ethylenediamine tetraacetic acid (EDTA) was the chelating agent. The molar ratio of EDTA to Bi3+ was found to play an important role in the formation of this morphology. These starlike BiVO4 samples exhibited a high visible-light-driven photocatalytic efficiency. For the degradation of methylene blue (MB) under visible-light irradiation (lambda > 420 nm), about 91% of the MB was degraded within 25 min. This is much higher than. for BiVO4 samples prepared by solid-state reaction (bulk BiVO4) and other hydrothermal synthesis methods. The reasons for the differences in the photocatalytic activities of these BiVO4 samples were further investigated.