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

Abstract

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.

Niobium addition enhancing the corrosion resistance of nanocrystalline Ti5Si3 coating in H2SO4 solution

“…By measuring the impedance response of specimens to small AC potentials, much information on the corrosion reaction, the mass transfer and the electrical charge transfer can be obtained. Furthermore, some important parameters associated with the passive film (or barrier layer), such as the ohmic resistance, capacitance and thickness, can be deduced and compared [36,37]. Fig.…”

“…MottSchottky analysis based on impedance measurements is a powerful in situ technique for assessing the electronic properties of the passive film. It has been used successfully in the past for the characterization of passive films formed on different passive materials [37,40,64]. According to semiconductor physical theory, the Mott-Schottky relationship expressing the potential dependence of the space charge capacitance C sc of a semiconductor film under depletion condition is described by Eq.…”

“…The significant difference in N d for the three specimens reflects a pronounced variation in the number of oxygen vacancies and/or cation interstitials in the passive films. It is commonly accepted that the carrier density (N d or N a ) is closely related to the stability and conductivity of the passive film, which in turn determines the corrosion resistance of the coating material underneath [37,51,71,73]. The higher carrier density is associated with more disordered structure of the passive film, and the lower carrier density signifies a more stable and dielectric passive film.…”

Effect of Nanotube Diameter on Photo-Electro-Chemical Properties of Carbon Quantum Dot Functionalized TiO2 Nanotubes

“…The different geometrical parameters for the two types of samples (prepared with different percentage of water contents in the electrolyte) are presented in Table I. Surface area for both type of samples were estimated by using formula [12]. in shape and regularly spaced which offer advantage in terms of the available surface area in contact with water/electrolyte for the PEC measurements.…”

Titania Nanotubes by Electrochemical Anodization for Solar Energy Conversion

“…Typical donor doping levels for TiO 2 nanotubes are on the order of 10 18 -10 20 cm −3 ; it should be noted that this doping level is quite high by semiconductor standards and should correspond to a relatively high conductivity. 75,[84][85][86] A higher doping density was observed using NH 4 F-based anodization electrolytes versus HF electrolytes; increasing the anodization voltage also resulted in increased doping density of the TiO 2 nanotubes. 85,87 Two-slope Mott-Schottky plots obtained by Muñoz indicated the presence of multiple defect levels identified by scanning the potential in the anodic direction.…”