Preparation and photocatalytic activity of WO3-TiO2/SiO2/Fe3O4 magnetite photocatalyst

Photoassisted catalytic decomposition with some semiconductors has been a promising method for the elimination of organic pollutants in water and atmosphere. It has been shown that TiO2 demonstrates the highest quantum yield among the popular semiconductors. However, the photocatalytic activity of TiO2 is not high enough for industrial purposes. Our work is concerned with the enhanced setting and reuse of suspended photocatalysts. The photocatalysts combined with magnetite make them be recycled easily from the treated water by magnetic force without complicated equipment and further processing. In order to further improve the photocatalytic efficiency of TiO2, several methods have been applied, such as increasing the external surface area of the photocatalysts, doping additives in TiO2 and modifying the TiO2 surface with metal or other semiconductors. Our aim in this work is to investigate the role of WO3 in enhancing the photocatalytic activity of TiO2. The magnetic photocatalyst WO3-TiO2/SiO2/Fe3O4 has been successfully prepared by sol-gel method with magnetite SiO2/Fe3O4 as a matrix. The catalyst samples were characterized by IR, XRD, SEM and XPS, respectively. The photocatalytic activity of the catalysts was investigated by photocatalytic decolorization of methylene blue. The results indicated that the photocatalytic activity of the composite photocatalyst with n(WO3)/n(TiO2) = 0.001 is higher than that of TiO2/SiO2/Fe3O4 and the photocatalytic efficiency still remains 98% after being reused for 3 times.