Ricerc@Sapienza

Here, a study aimed to determine the phase transition temperature of
titanium dioxide nanotubes, both in the presence and in the absence of a Ti layer
underneath, is reported. Titania nanotube arrays with different diameters and wall
thickness were synthesized via anodic growth at different potential values on a titanium
foil. Ex and in situ high-temperature X-ray diffraction measurements were performed,
respectively, on the arrays as such and on the powder obtained by detaching the
nanotubes from the metallic substrate. Our results demonstrate that the presence of Ti
dramatically influences the crystallization process decreasing the temperature formation
of rutile, which tends to appear initially at the Ti/TiO2 interface