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Reduction of oxygen on Teflon-backed platinum black electrodes

✍ Scribed by W. Vogel; J. Lundquist; A. Bradford


Publisher
Elsevier Science
Year
1972
Tongue
English
Weight
754 KB
Volume
17
Category
Article
ISSN
0013-4686

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✦ Synopsis


It is not yet possible to determine in detail the precise micro-structure of porous gas electrodes. It has therefore become customary to analyse actual electrode polarization curve in terms of an electrode model. The degree of cotidence in such analyses is lessened by the fact that certain parameters of the model are not amenable to direct experimental measurement and may have no strict physical counterpart in reality. This paper describes experiments with porous electrodes requiring no artificial parameters for their analysis except in the limiting current region. The electrodes consisted essentially of a thin porous layer of Teflon in intimate contact with a thin porous layer of platinum black. The results fully validate the flooded pore model. The observed polarization curves match the theoretical curves calculated entirely from independently measured data. R-11 n'est pas encore possible de pr&iser le d&ail de la microstructure des &ctrodes de verre poreuses. 11 est done actuellement usuel d'analyser les courbes de polarisation d'une 6lectrode. d'apr&s un mod& hypothbtique. La confiance il accorder & de telles analyses est amoindrie du fait que certains param&res du mod&le ne sont pas susceptibles de mesures exp&imentales directes et pourraient db lors n'avoir aucune signification physique concrete. Description d'exp&iences sur des &c&odes poreuses, dont l'interpr&ation ne sollicite aucun paramhtre artificiel, sauf dans la r&ion du courant limite. Les &ctrodes sent constitu&s essentiellement par une couche poreuse mince de Tbflon en contact intime avec une couche poreuse mince de noir de platine. Les r6sultats satisfont parfaitement g un modkle d'6coulement poreux. Les courhes de polarisation observ6es concordant avec les courbes th&oriques entitrement calcul&s B pa&r de r&uItats independants. -g-Es ist bis jetzt noch nicht maglich. die genaue Mikrostruktur einer por6sen Gaselektrode zu bestimmen. Es war deshalb iiblich, Elektrodenpolarisationskurven mit Hi& eines Elektrodenmodells zu untersuchen. Das Vertrauen zu solchen Untersuchungen wird durch die Tatsache vermindert, dass gewisse Gr&sen in diesem Model1 nlcht fiber direkte urperimentelle Messungen zug%nglich sind, und in Wirklichkeit such keine exakte physikalische Bedeutung haben. Diese Arbeit beshreibt Experimente an por&en Elektroden, welche keine solchen kiinstlichen Parameter zur analyse ben6tigen. Eine Ausnahme bildet hier lediglich die Grenzstromregion. Die Elektrode besteht im wesentlichen aus einer diinnen Teflonschicht, welche in engem Kontakt mit einer diinnen por&en Schicht von Platinschwarz steht. Die erhaltenen Resultate erffillen das Model1 dcr durchstrtimten Poren. Die beobachteten Polarisationskurven stimmen mit den aus unabh&ngig gemessenen Gr&ssen berechneten theoretischen Kurven vollstiindig iiberein.


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