High temperature diffraction study of in-situ crystallization of TiO 2 photocatalysts

By virtue of a high surface-to-volume ratio, very high photocatalytic activity has already been demonstrated for nanostructured TiO2 with various morphologies such as nano-powders, nano-rods, nano-wires, nano-fibers, nano-belts, nano-tubes, and thin films. Although a lot of progress has been achieved in these forms of TiO2, the poor recuperability and reutilization limitation for nano-powders and processing difficulty for nano-fibres or nano-tubes are still challenges for their commercial applications. In this paper, the synthesis and characterisation of in-situ crystallization of TiO2 nanotubes from the precursor of as-anodizedi amorphous TiO2 nanotubes after annealing at temperatures up to 900 °C are described. The resultant microstructures and composition depth profiles are discussed in terms of ion-beam analysis and grazing-incidence synchrotron radiation diffraction.