The growth kinetics of thin anodic WO3 films investigated by electrochemical impedance spectroscopy

Metikoš‐Huković, Mirjana; Grubač, Zoran

doi:10.1016/s0022-0728(03)00342-5

Cited by 53 publications

(41 citation statements)

References 40 publications

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“…j ss increases almost linearly with potential scan rate, according to expected for anodic growth through a ''high-field mechanism" and commonly found for oxide growth on other valve metals as tungsten [21]. At higher potentials (zone III) anodic growth continues, probably following the same oxide growth mechanism.…”

Section: General Electrochemical Behavioursupporting

confidence: 69%

Characterization of the anodic growth and dissolution of antimony oxide films

Pérez

Teijelo

2009

Journal of Electroanalytical Chemistry

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Section: General Electrochemical Behavioursupporting

confidence: 69%

Characterization of the anodic growth and dissolution of antimony oxide films

Pérez

Teijelo

2009

Journal of Electroanalytical Chemistry

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“…Therefore, the difference in the intensity of the specific adsorption may contribute to the difference between the iep and pzc. It is also reported that [30] the phosphate ions, which are incorporated in the WO 3 (s) film during the dissolution experiments but not during the case zeta potential measurements, may change slightly the composition of the oxide film.…”

Section: Zeta Potential Of Wo 3 (S) Powdermentioning

confidence: 99%

Dissolution kinetics of WO3 in acidic solutions

Anık

Cansizoglu

2006

J Appl Electrochem

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Potentiostatic polarization and rotating disk electrode techniques were used to obtain the rate constant for the dissolution of electrochemically-formed (at 1 V) WO 3 on tungsten (W) in acidic solutions. The corresponding rate constant for the chemical dissolution of WO 3 (s) powder was found by measuring the dissolved tungsten concentration as a function of time and pH. The chemical dissolution experiments supported the view that the ratedetermining step in the anodic reaction of W in acidic solution is the chemical dissolution of WO 3 (s) formed on the metal surface. Zeta potential measurements gave the isoelectric point (iep) of the WO 3 (s) powder as pH 1.5, a value that was somewhat smaller than the point of zero charge (pzc) of WO 3 (s) formed on W metal (pH 2.5). This difference was attributed to the highly hydrated nature of the oxide film formed on W metal in aqueous systems.

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“…Large values of ␣ Ϸ 0.5 ͑or even higher͒ were often used and estimated for these well-passive and well-protective film covered metals under steady-state or quasisteady-state conditions. For examples ␣ = 0.992 was estimated for passivated Zn, 22 0.42-0.58 for passivated W, 16,17 and 0.39 for passivated Fe; 20 ␣ = 0.5 was assumed and used for passivated Ti, 1 0.5 Ϯ 0.05 was quoted and used for passivated Fe, Cr, Ni, their alloys, 13,18 etc.…”

Section: C42mentioning

confidence: 99%

Studying on the Point-Defect-Conductive Property of the Semiconducting Anodic Oxide Films on Titanium

Kong

Lü

Feng

et al. 2009

J. Electrochem. Soc.

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By using electrochemical measurement techniques and based on the point-defect model ͑PDM͒, this work studied the point-defectconductive property of the n-type semiconducting anodic oxide film formed on titanium under steady-state condition within the passive potential region of ca. 0-7 V in 1.0 M HClO 4 solution. The point-defect transport property was characterized by the steady-state current density ͑i ss ͒ through the film and the diffusion coefficient ͑D O ͒ of the point defects in the film. It was demonstrated that with the increase of the film formation potentials, i ss ͑and D O ͒ show an exponentially dependent increase on the potential. This behavior of the oxide films formed on titanium is to some extent different from that of some other n-type anodic oxide films. The influence of potential on the changes in structure and crystallization of the oxide film on titanium was proposed to be taken as a reason for the potential-dependence of i ss ͑and D O ͒ observed in this work. It was also shown that within the passive potential region most of any change in the applied potential does appear predominantly as a change in the potential drop within the oxide film ͑only ϳ6% of that drops across the film/solution interface͒. Additionally, a question about the values of the polarizability of the oxide film/solution interface ͑␣͒ used and estimated within the frames of the PDM was raised and discussed at the end of this paper.The titanium/TiO 2 film/electrolyte interface system has received more and more attention because it has a wide variety of scientific interest and technological applications, including corrosion inhibition, 1,2 dye-sensitized solar energy conversion cells, 3 electrocatalysis ͑or in terms of dimensionally stable anodes͒, 4,5 and the use in photoelectrocatalytical degradation of certain categories of organic pollutants in wastewater, 5-7 etc. In close relation with these applications of titanium-based electrodes, the charge transfer through the oxide film formed on titanium is the most fundamental and essential issue, which has been intensively studied, but has not yet been completely understood. Although there have been considerable experimental study reports about the electron conductive property of the oxide film on titanium, 5,8-12 only very few papers have dealt with the ion-conductive property of the oxide films on titanium. 5 The point-defect model ͑PDM͒ ͑which was developed by Macdonald and Macdonald, 13 Macdonald et al.,14 and Macdonald 15 ͒ and the related treatments such as the mixed-conduction model and the surface charge approach ͑which were developed by Bojinov, 16 Metikos-Hukovic and Grubac, 17 and Bojinov et al. 18 ͒, provide a microscopic description of the migration of the Schottky point defects under the influence of the electrostatic field in the passive oxide film during the film growth under steady-state conditions. Although the validity of the PDM was tested and verified by experimental results for passive films on many metals such as Fe

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The growth kinetics of thin anodic WO3 films investigated by electrochemical impedance spectroscopy

Cited by 53 publications

References 40 publications

Characterization of the anodic growth and dissolution of antimony oxide films

Characterization of the anodic growth and dissolution of antimony oxide films

Dissolution kinetics of WO3 in acidic solutions

Studying on the Point-Defect-Conductive Property of the Semiconducting Anodic Oxide Films on Titanium

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