High temperature diffraction studies of in-situ crystallization of nanostructured TiO2 photocatalysts

Abstract

The in-situ crystallization of anatase and rutile on chemically-treated Ti-foils in the temperature range 20-900 degrees C has been investigated using synchrotron radiation diffraction and x-ray diffraction. The processing methodology has a profound influence on the morphology, crystallite size and growth rate of nanostructured TiO2. The anatase formed was metastable and transformed to rutile at similar to 800 degrees C. Increasing the temperature from 400 to 900 degrees C caused the sharpening of anatase (101) peaks and resulted in a concomitant coarsening in crystallite size. The surface of annealed samples exhibited TiO2 nanorods, nanowires or nanotubes depending on the processing method. Ion-beam analysis has indicated the existence of composition gradation within the annealed TiO2 samples at the near-surface. © 2012, The American Ceramic Society.