Effect of reaction time on the formation of TiO2 nanotubes prepared by hydrothermal method

TiO2 nanotubes have been prepared by hydrothermal method. The influence of reaction time on the formation of TiO2 nanotubes has been studied. X-ray diffraction results indicate that the TiO2 nanocrystallites consist predominantly of anatase phase with small amount of rutile phase. The scanning electron microscope images reveal the formation of TiO2 nanotubes. Transmission electron microscope (TEM) images further confirm the formation of TiO2 nanotube structure. The nature of the structure formed was found to be dependent on the reaction time. The diameter and length of the nanotubes were measured to be 11.23 nm and 260 nm respectively. Optical absorption studies reveal that the absorption edge shifts towards longer wavelength (red shift) with increase in hydrothermal reaction time. The band gap energy was found to be 3.6 eV and 3.5 eV for TiO2 nanotubes prepared using 10 h and 16 h reaction time.