TiO2 nanotubes were prepared by hydrothermal treatment of TiO2 powder in NaOH aqueous solution at different temperatures. The calcined temperature play an important role in the morphology, structure and optical gap of TiO2 nanotubes. The samples were characterized using x-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-Vis techniques. SEM images indicate that the diameter of the nanotubes is about 19–30 nm. The optical band gap (Eg) energy is estimated to be about 3.4– 4.5 eV for as prepared nanotubes, which is greater than 3.31 eV of bulk TiO2.
