ZnWO4 photocatalyst with high activity for degradation of organic contaminants

ZnWO4 nanoparticle photocatalyst has been prepared by annealing treatment of hydrothermal sample, and the high photocatalytic activity was explored. The crystalline of ZnWO4 photocatalysts were improved as the increase of annealing temperature and time. It was found that ZnWO4 nanoparticle catalysts exhibited a high photocatalytic activity, not only in the decomposition of formaldehyde in gaseous, but also in the degradation of RhB in water. The highest photocatalytic activity both appeared at 450 degrees C for I It due to good crystallization and high surface area. The photocatalytic activity of ZnWO4 was a little higher than that of P-25 (Degussa) in gaseous and lower than that of P-25 (Degussa) in aqueous. The main reason is that the dispersion of ZnWO4 Powders in aqueous is not good due to its high density. The surface area, crystal size, dispersion and crystalline are important factors, which influence the photocatalytic activities of ZnWO4 catalysts. (c) 2006 Elsevier B.V. All rights reserved.