Characterization of Mo doped TiO2 and its enhanced photo catalytic activity under visible light

Transition metal doping into the TiO2 lattice can expand the response of these metal oxide nano particles to the visible region. In view of this, Mo6+ ion is doped into the TiO2 lattice in order to understand the mechanism of its photo response. The prepared photocatalysts were characterized by X-ray diffraction, UV-Visible absorption spectroscopy, UV-Visible diffuse reflectance spectroscopy, SEM, EDX, FTIR and BET specific surface area techniques. The characterization results have confirmed the incorporation of metal ions into TiO2 lattice. XRD analysis shows no change in crystal structure except a slight variation in crystallite size and elongation along the c-axis with increase in the concentration of the dopant. Diffuse reflectance measurements showed a shift in the band edge position to longer wavelengths and an extension of the absorption to the visible region. The photo degradation efficiencies of these catalysts were studied with Tebuconazole pesticide as model pollutant. Under UV light, undoped catalyst showed higher activity than doped catalyst. But in the case of visible light irradiation Mo doped TiO2 with intermediate dopant concentration of 0.06 atom % had the highest photocatalytic reactivity. This may be due to the narrowing of band gap so that it could effectively absorb the light of longer wavelength. The degradation path way was followed by UV-Visible spectroscopy.