Y-Dy DOPED AND CO-DOPED TiO2. ENHANCEMENT OF PHOTOCATALYTIC ACTIVITY UNDER VISIBLE LIGHT IRRADIATION

Nano-sized Y-Dy doped and co-doped TiO2 particles were synthesized using the sol-gel method and Ti(OBu)(4) as TiO2 precursor for sol-gel process. Their structure and optical properties were examined by XRD, Raman and UV-Vis absorption spectroscopies. The XRD and Raman analysis of samples calcined at 400 degrees C for 2 h showed that all relatively sharp reflections and bands can be attributed to the anatase form of TiO2. Ground state diffuse reflectance absorption studies reveal that both Y and Dy dopant cause deviations of the band gap to higher energies attesting that co-doping the TiO2 with Y and Dy could enhance the photo-catalytic activity by delaying the electron-hole recombination by means of higher energy band gaps. However co-doping TiO2 at a level of 3% (Y, Dy) leads to a significant decrease in the crystallite size of photocatalyst and to a great enhancement of the photodegradation efficiency of methylene blue (MB) under visible light.