Nanostructured BiVO4 photocatalysts synthesized via a polymer-assisted coprecipitation method and their photocatalytic properties under visible-light irradiation

Nanostructured BiVO4 photocatalysts were synthesized by a coprecipitation process in the presence of sodium carboxymethylcellulose (CMC), which acts as a steric stabilizer during the formation and growth of the BiVO4 nanoparticles. Samples with different contents of CMC were prepared in order to study the effect of the polymer on the final morphology of the oxide. The synthesized samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), and adsorption-desorption isotherms (BET). The presence of CMC during the first stage of BiVO4 synthesis, promoted the formation of granular particles controlling its morphology and favoring its dispersion. The BiVO4 monoclinic polymorph (m-BiVO4) was obtained free of the tetragonal crystalline form (t-BiVO4) by annealing at different temperatures, which were influenced by CMC content: 400 degrees C (0.5 wt %), 450 degrees C (3.0 wt %), and 350 degrees C (6.0 and 9.0 wt %). BiVO4 nanoparticles showed photocatalytic activity, as they bleached an aqueous solution a rhodamine B (rhB) under visible-light irradiation. The photocatalytic activity of the BiVO4 samples was directly correlated with the amount of CMC added during the synthesis process. (C) 2011 Elsevier Masson SAS. All rights reserved.