Photocatalytic behavior of WO3-loaded TiO2 in an oxidation reaction

It has been found that the photocatalytic activity of TiO2 toward the decom position of Ip-dichlorobenzene (DCB) aqueous solution can be greatly improv ed by loading WO3 On the TiO2 surface. In this work, we have investigated t he role of WO3 in enhancing the photocatalytic activity of TiO2. The surfac e structure of WO3/TiO2 was characterized by surface acidity measurements a nd by surface analysis with XPS and TEM techniques. WO3 covers the surface of TiO2 with monolayer thickness and the WO3/TiO2 particles are better able to disperse than the pure TiO2 suspended in aqueous solution. The role of WO3 in enhancing the photocatalytic activity of TiO2 has been studied by ut ilizing the photocatalysts prepared in a film form. First, benzene and 2-pr opanol were used as gas-phase model compounds. WO3/TiO2 demonstrates 3.6-5. 9 times the photocatalytic activity of pure TiO2. Second, methylene blue co ated on the photocatalysts was applied in the photocatalytic oxidation reac tion. WO3/TiO2 presents only 1.4-1.5 times the photocatalytic activity of p ure TiO2 in decomposing the coated methylene blue. Based upon these observa tions, the mechanistic role of WO3 in the photocatalytic oxidation reaction has been suggested. (C) 2000 Academic Press.