Role of water content in anodization of titanium to fabricate TiO2 nanotubes and its properties

The effect of water content in anodization of Ti foil on photoelectrochemical activity of TiO
₂
nanotubes fabricated were studied and optimized. The mixed phase of TiO
₂
was confirmed from X-ray diffraction and their morphological changes with respect to increase in water content were analyzed using High Resolution Scanning Electron Microscope. The optical band gap of TiO
₂
can be effectively tuned from 3.023(2) to 2.601(7) eV by varying the water content in anodization. The maximum photocurrent density of 2.5 mA/cm
²
was observed for the TiO
₂
sample with higher crystallinity. These results suggest that the higher crystallinity with ordered nanotubes and lesser band gap act as a key role in improving the photoelectrochemical activity of TiO
₂
.