Preparation of F-doped titania nanoparticles with a highly thermally stable anatase phase by alcoholysis of TiCl4

Pure anatase is a metastable phase and inclined to (transform) be transformed into rutile structure under heating over than 500 °C, which limits its suitability for high-temperature applications. Hitherto much research efforts have been made to increase the stability temperature of anatase structure. However, metallic doping usually introduced metallic oxides into titania at high temperature, and many nonmetallic doping are not competent for increasing the stability temperature of anatase structure up to 900 °C. In this study, F-doped anatase TiO₂ nanoparticles were conveniently prepared via the alcoholysis of TiCl₄ and the as-prepared product shows very high stability temperature up to 1000 °C before being transformed into rutile structure phase. On the basis of XPS results of F-doped titania annealed at different temperature, it is learned that the F atoms were anchored on the crystal planes of anatase in favor of decreasing the energy faces of anatase and stabilizing the anatase structure till annealed at 1300 °C all the anatase were transformed into rutile phase.