Photocatalytic Degradation of Aqueous Alachlor with Visible-Light Active Mesoporous WO3/TiO2

Mesoporous WO3/TiO2 photocatalysts were prepared by sol gel method using Pluronic P123 as the structure directing agent. The low angle XRD and BET analysis confirmed the mesoporous nature of the materials. The isomorphic substitution of W6+ into TiO2 was evident from the slight shift in the XRD patterns. The XPS spectrum confirmed the presence of W6+ and Ti4+ in WO3/TiO2. The DRS UV-Vis spectrum exhibited red shift in the absorbance spectrum of TiO2 which was mainly due to the formation of W6+ impurity states below the conduction band edge of TiO2. The photocatalytic activity of mesoporous WO3/TiO2 materials was evaluated in the degradation of aqueous alachlor using solar light irradiation. Pristine mesoporous TiO2 showed low visible-light activity due to its weak absorption of solar light. Mesoporous WO3/TiO2 photocatalysts exhibited higher photocatalytic activity than pristine mesoporous TiO2 and WO3. Hence, isomorphic substitution of W6+ in TiO2 found to play a major role in the enhancement of photocatalytic activity under solar light.