Ultrasound assisted synthesis of monoclinic structured spindle BiVO4 particles with hollow structure and its photocatalytic property

Bismuth vanadate (BiVO4) spindle particles with monoclinic scheelite structure have been successfully synthesized via a facile sonochemical method. The as-prepared BiVO4 photocatalyst exhibited a hollow interior structure constructed from the self-assembly of cone shape primary nanocrystals. A possible oriented attachment growth mechanism has been proposed based on the results of time-dependent experiments, which indicates the formation of spindle particles is mainly attributed to the phase transformation procedure induced by ultrasound irradiation. A series of morphology evolutions of BiVO4 from compact microspheres, to hollow microspheres, and then to spindle particles have been arrested in the process of sonochemical treatment. Optical absorption experiments revealed the BiVO4 spindle had strong absorption in the visible light region. A much higher photocatalytic activity of these spindle particles was found in comparison with the SSR-BiVO4 material for degradation of rhodamine-B under visible light irradiation, which may be ascribed to its special single-crystalline nanostructure.