Photocatalytic activity of needle-like TiO2/WO3−x thin films prepared by chemical vapour deposition

Abstract

The enhanced photocatalytic activity of needle-like TiO 2 /WO 3− x (0 < x ≤ 0.3) composite thin films is demonstrated in the degradation of stearic acid, a model system for the organic pollutants typically present on window surfaces. The films were synthesised by atmospheric pressure chemical vapour deposition from reaction of tungsten and titanium chlorides with ethanol or ethyl acetate oxygen sources, respectively, and characterised by X-ray diffraction, Raman spectroscopy, SEM and AFM. The increase in activity of films is explained in terms of an effective vectorial charge separation at the interface of the two oxide semiconductors. The interaction of water with the surface of the TiO 2 /WO 3− x composite film is also discussed after water droplet contact angle measurements. ► Morphology-controlled synthesis of thin-film TiO 2 /WO 3− x composite by atmospheric-pressure chemical vapour deposition (APCVD). ► The composite film is proven to be more efficient than its individual components for stearic acid degradation under UVA and UVC lights. ► The enhancement of activity is explained in terms of a more efficient vectorial charge separation. The enhanced photocatalytic activity of needle-like TiO 2 /WO 3− x (0 < x ≤ 0.3) composite thin films is demonstrated in the degradation of stearic acid, a model system for the organic pollutants typically present on window surfaces. The films were synthesised by atmospheric pressure chemical vapour deposition (APCVD) from reaction of tungsten and titanium chlorides with ethanol and ethyl acetate as oxygen sources, respectively, and characterised by X-ray diffraction, Raman spectroscopy, SEM and AFM. The increase in activity of films is explained in terms of an effective vectorial charge separation at the interface of the two oxide semiconductors. The interaction of water with the surface of the TiO 2 /WO 3− x composite film is also discussed after water droplet contact angle measurements.