Optical and structural properties of TiO2 nanopowders with Co/Ce doping at various temperature

In this study, preparation of 2 mol% Ce and 4 mol% Co doped TiO2 nanopowders via sol–gel process have been investigated. The effects of Co and Ce doping and calcination temperature (475–1000 °C) on the structural and optical properties of titania nanopowders studied by X-ray diffraction (XRD), scanning electron microscope, transmission electron microscope and UV–Vis absorption spectroscope. XRD results showed that, Titania rutile phase formation in ternary system (Ti–Co–Ce) was inhibited by Ce4+ and promoted by Co4+ co-doped TiO2 in high temperatures (500–700 °C) and 61 mol% anatase composition is retained even after calcination at 800 °C. The optical absorption spectrum indicates that the TiO2 nanoparticles have a direct band gap of 3.21 eV. But optical band gap of the doped TiO2 (2 mol% Ce and 4 mol% Co) was found to be 3.14–3.20 eV.