Photocatalytic Activity of TiO 2 ‐WO 3 Composites

TiO 2 ‐WO 3 photocatalysts were prepared in a vacuum evaporator by impregnation of TiO 2 with WO 2 dissolved in an H 2 O 2 solution (30%) and followed by calcination at 400 and 600 ∘ C. XRD analyses showed that at 400 ∘ C monoclinic phase of WO 3 was dominated whereas at 600 ∘ C both monoclinic and regular phases of WO 3 were present. Modification of TiO 2 by WO 3 caused increasing in the absorption of light to the visible range. TiO 2 and photocatalysts modified with low amount of WO 3 (1–5 wt.%) showed high adsorption of Acid Red (AR) on their surface and enhanced photocatalytic activity under UV irradiation. Under visible light irradiation, TiO 2 ‐WO 3 photocatalysts prepared at 400 ∘ C were more active for AR decomposition than those prepared at 600 ∘ C suggesting that monoclinic phase of WO 3 is more active under visible light than regular WO 3 . Although TiO 2 ‐WO 3 photocatalysts appeared to be active under visible light for decomposition of AR, the UV irradiation was more efficient.