Abstract
X-ray diffraction (XRD) and scanning electron microscopy (SEM) have been used to characterize physical structure of IrO2+Ta2O5 films over the whole composition range by thermodecomposition of chloride solutions heated at 450°C. Solid solubilization between Ta component and IrO2 rutile in the mixed films was measured, and three typical surface morphologies of the oxide coatings were observed. The surface electrochemical properties of Ti/IrO2-Ta2O5 electrodes were studied by cyclic voltammetry at varying potential scan rate, and a ‘double-layer’ electrochemical structure containing the ‘inner’ and ‘outer’ layers has been distinguished. The voltammetric charge appears to decline with the decrease of grain size of oxide coatings as a result of the effect of surface tension. However, the coatings of 70% IrO2+30% Ta2O5 with the finest grains still exhibit the highest apparent activity for oxygen evolution evaluated by the anodic current at a constant potential. This result is interpreted by the measurements of open-circuit potential (E oc) and double-layer capacitance (C dl) using electrochemical impedance spectroscopy (EIS). Thereby, the reliability of voltammetric charge obtained in ‘double-layer’ potential region in determining the real electrocatalytic activity for O2 evolution has been discussed.
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References
H. B. Beer, US patent US549194 (1966); Idem., US710551 (1968).
S. Trasatti, Electrochim. Acta 45 (2000) 2377.
S. Nijjer, J. Thonstad and G. M. Haarberg, ibid. 46 (2001) 3503.
G. Lodi, A. de Battisti, G. Bordin, C. de Asmundis and A. Benedetti, J. Electroanal. Chem. 277 (1990) 139.
C. Comninellis and G. P. Vercesi, J. Appl. Electrochem. 21 (1991) 335.
J. Rolewicz, C. Comninellis, E. Plattiner and J. Hinden, Electrochim. Acta 33 (1988) 573.
Idem., Chimia 42 (1988) 75.
Y. E. Roginskaya, O. V. Morozova, E. N. Loubnln, A. V. Popov, Y. I. Ulitina, V. V. Zhurov, N. A. Ivanov and S. Trassati, J. Chem. Soc. Faraday Trans. 89 (1993) 1707.
Y. E. Roginskaya and O. V. Mororozova, Electrochim. Acta 40 (1995) 817.
J. M. Hu, H. M. Meng, J. Q. Zhang, J. X. Wu, D. J. Yang and C. N. Cao, J. Mater. Sci. Lett. 20 (2001) 1353.
F. Cardarelli, P. Taxil, A. Savall, Ch. Comninellis, G. Manoli and O. Leclerc, J. Appl. Electrochem. 28 (1998) 245.
G. P. Vercesi, J. Rolewicz, C. Comninellis and J. Hinden, Thermochim. Acta 176 (1991) 31.
R. Otogawa, M. Morimitsu and M. Matsunaga, Electrochim. Acta 44 (1998) 1509.
S. Trasatti, “Electrodes of Conductive Metallic Oxides,” Part A (Elsevier, Amsterdam, 1980).
R. Boggio, A. Carugati and S. Trasatti, J. Appl. Electrochem. 17 (1987) 828.
L. A. da Silva, V. A. Alves, S. C. de Castro and J. F. C. Boodts, Colloids and Surfaces A: Physicochem. Eng. Aspects 170 (2000) 119.
C. Angelinetta and S. Trasatti, Mater. Chem. Phys. 22 (1989) 231.
S. Pizzini and G. Buzzanca, Mater. Res. Bull. 7 (1972) 449.
H. P. Klug and L. E. Alexand, “X-Ray Diffraction Procedures for Polycrystalline and Amorphous Materials” (Wiley, New York, 1974).
Natl. Bur. Std. (U.S.) Mono. 25, Sec. 4 (1965).
L. L. Xu, “The Semiconductor Fundamental of Oxides and Compounds” (Xi'an Electronic Science & Technology University Press, Xi'an, 1991) (in Chinese).
L. A. de Farla, J. F. C. Boodts and S. Tasatti, Electrochim. Acta 37 (1992) 2511.
S. Ardizzone, A. Carugati and S. Trasatti, J. Electroanal. Chem. 126 (1981) 287.
S. Tasatti, Electrochim. Acta 36 (1991) 225.
D. Galizzioli, F. Tantardini and S. Trasatti, J. Appl. Electrochem. 4 (1974) 52.
A. de Oliveira-Sousa, M. A. S. da Silva, S. A. S. Machado, L. A. Avaca and P. de Limaneto, Electrochim. Acta 45 (2000) 4467.
L. D. Burke and O. J. Murphy, J. Electroanal. Chem. 96 (1979) 19.
S. Ardizzone, G. Fregonara and S. Trasatti, Electrochim. Acta 35 (1990) 263.
C. P. de Pauli and S. Trasatti, J. Electroanal. Chem. 396 (1995) 161.
D. Baronetto, N. Krstajic and S. Tasatti, Electrochim. Acta 39 (1994) 2359.
W. S. Brey and B. H. Davis, J. Colloid and Interface Science 70 (1979) 10.
L. A. da Silva, V. A. Alves, M. A. P. da Silva, S. Trasatti and J. F. C. Boodts, Electrochim, Acta 42 (1997) 271.
V. A. Alves, L. A. da Silva and J. F. C. Boodts, J. Appl. Electrochem. 28 (1998) 889.
P. Rasiyah and A. C. C. Tseung, J. Electrochem. Soc. 131 (1984) 803.
A. Hickling and S. Hill, Discussions Faraday Society 1 (1947) 236.
A. C. C. Tseung and S. Jasem, Electrochim. Acta 22 (1977) 31.
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Hu, Jm., Zhang, Jq., Meng, Hm. et al. Microstructure, electrochemical surface and electrocatalytic properties of IrO2+Ta2O5 oxide electrodes. Journal of Materials Science 38, 705–712 (2003). https://doi.org/10.1023/A:1021840426997
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DOI: https://doi.org/10.1023/A:1021840426997