Visible-light-induced BiVO4 photocatalyst with monoclinic scheelite structure has been successfully synthesized via a facile sonochemical method. The as-prepared BiVO4 photocatalyst exhibited relatively high surface areas, consisting of primary nanocrystals with average size of ca. 50 nm. The BiVO4 nanocrystals showed a strong absorption in the visible light region and the band gap was estimated to be ca. 2.45 ev, representing an obvious blue-shift compared with that of the bulk sample. The photocatalytic activities were also evaluated by decolorization of methyl orange under visible light (lambda > 400 nm). The results indicate that the photodegradation rate of as-prepared BiVO4 nanocrystals is quite high, up to 90% in 30 min, which is much better than that of the reference sample prepared by solid-state reaction (ca. 8%) and the standard photocatalyst P25 (ca. 6%) under the same conditions. (c) 2006 Elsevier B.V. All rights reserved.