Effect of Anodizing Potential on the Formation and EIS Characteristics of TiO₂Nanotube Arrays

In the present work, well ordered arrays of TiO 2 nanotubes were obtained by anodization at different voltages of Ti foil in a solution containing anhydrous ethylene glycol + 0.27 M NH 4 F and 0.2 wt% water. A detailed study has been performed to evaluate the morphology and electrochemical characteristics of the anodized Ti foil synthesized in different anodization potentials. Correlation between the physical properties and the dimensional aspect of TiO 2 nanotubes was examined. In this paper, we report the electrochemical characteristics of the Ti/TiO 2 nanotube surfaces from Tafel plots. The electronic properties of TiO 2 nanotubular layers were also determined by electrochemical impedance spectroscopy analysis (EIS). EIS is considered to be a valuable tool that allows determining barrier oxide parameters. A linear dependence of barrier thickness on the anodizing voltage was verified from 20 to 50 V, the proportionality constant of the barrier layer thickness in relation to the applied anodizing voltage was estimated from the proposed equivalent circuit.