Investigation of surface microstructural, optical and photocatalytic activity of tungsten doped titanium dioxide thin films deposited by spray pyrolysis

Abstract

In the present study, un-dopedtitanium dioxide (TiO2) and tungsten (W) doped TiO2 thin films have been deposited onto plain glass substrates at 450 °C using the spray pyrolysis method. The surface morphology, structural parameters, optical properties and photocatalytic activity of un-doped TiO2 and W doped TiO2 thin films doping withconcentrations of 2, 4, 6 and 8 at.% were investigated. The field emission scanning electron microscopy (FESEM) showed several forms of surface morphology of un-dopedTiO2 and W doped TiO2 thin films. Grain size and diameter of reticulated fiber (0.88 to 1.80 m and 0.267 to 0.187 m) were observed from the images of FESEM.Energy dispersive X-ray analysis confirms the presence of Ti, W and O.X-ray diffraction study shows the anatase (tetragonal structure) phase in the un-dopedTiO2 and W doped TiO2 thin films, with crystallite sizes ranging from 18 to 36 nm. The optical band gap was calculated from the UV-Vis spectra and found 3.34 eV for un-doped TiO2and 3.27, 3.22, 3.17 and 3.05 eV for 2, 4, 6 and 8 at.% W doped TiO2 thin films, respectively. The photocatalytic activity was evaluated by the degradation of methylene blue using UV light. The photocatalytic activities revealed that the 6 at.% W doped TiO2 thin films exhibit 76% degradation efficiency.