The oxygen transfer process on solid oxide/noble metal electrodes, studies with impedance spectroscopy, polarization and isotope exchange

Boukamp, B.A. and Hassel van, B.A. and Vinke, I.C. and Vries de, K.J. and Burggraaf, A.J. (1993) The oxygen transfer process on solid oxide/noble metal electrodes, studies with impedance spectroscopy, polarization and isotope exchange. Electrochimica Acta, 38 (14). pp. 1817-1825. ISSN 0013-4686

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Abstract:	The electrochemical oxygen transfer process at the yttria stabilized zirconia (YSZ) and Fe-implanted YSZ, and at the erbia stabilized bismuth oxide (BE25) surface is studied with dc polarization and impedance spectroscopy using gold electrodes, and with 18O gas phase exchange. The surface modification by Fe-implantation increases the exchange current density up to a factor of 50, but analysis of the impedance spectra at different polarization levels indicates that the type of electrode reaction is not changed by the implantation. Inductive effects at cathodic polarizations are interpreted with a stepwise transfer of electrons. Isotope exchange experiments show an increase in adsorption/reaction sites at the surface after implantation. The high exchange current density, I0, for BE25 is independent of type of electrode but does depend on electrode morphology. I0 can be equated to the surface oxygen exchange rate, indicating that the entire electrolyte surface is active in the electrode exchange process. Qualitative interpretation of the impedance spectra measured at different levels of polarization results in a model where adsorbed oxygen species diffuse over the oxide surface, while charge transfer occurs across the surface.
Item Type:	Article
Copyright:	© 1993 Elsevier Science
Research Group:	Inorganic Materials Science (IMS)
Link to this item:	http://purl.utwente.nl/publications/12663
Official URL:	http://dx.doi.org/10.1016/0013-4686(93)80303-H
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Metis ID: 106844