Study of adsorption of oxygen on -Al2O3 + Au and - Al2O3 + Pt: Work function measurements ; proposition of a model.

Nicolas Guillet 1, 2, 3 Alain Rives 4 René Lalauze 1, 2, 3 Christophe Pijolat 1, 2, 3
1 LPMG-EMSE - Laboratoire des Procédés en Milieux Granulaires
2 MICC-ENSMSE - Département Microsystèmes, Instrumentation et Capteurs Chimiques
3 SPIN-ENSMSE - Centre Sciences des Processus Industriels et Naturels
4 LCL - Laboratoire de catalyse de Lille
Abstract : To improve the understanding of the electrochemical effects observed on an original potentiometric gas sensor, interactions of oxygen with the device were investigated. This gas sensor is made of a solid electrolyte (treated Na-β-alumina) associated with two metallic electrodes (gold and platinum) located in the same gas mixture. Adsorption of charged oxygen species, considered responsible for the electrical response developed by the sensor, was investigated by work function measurements. Results showed that charged oxygen species only form on partially gold or platinum covered solid electrolyte. Comparison of these results with those obtained in a previous calorimetric study of interactions between oxygen and the same materials suggests the existence of at least two different oxygen species adsorbed on the surface of the sensitive element. The first one, located on the solid electrolyte surface, is neutral and characterized by an endothermal reaction of formation. The second one is charged and probably produced at the gas/solid electrolyte/metallic electrode interface. A mechanism based on the concept of "three phase boundary" and similar to the "reverse spillover" phenomenon is proposed to account for the adsorption of these oxygen species.
Keywords : Oxygen adsorption β-Alumina Gold Platinum Work function Kelvin probe
Type de document :
Article dans une revue
Applied Surface Science, Elsevier, 2003, 210 (3-4), pp.286-292. 〈10.1016/S0169-4332(02)01466-6〉
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https://hal-emse.ccsd.cnrs.fr/emse-00431871
Contributeur : Andrée-Aimée Toucas <>
Soumis le : vendredi 13 novembre 2009 - 13:26:36
Dernière modification le : mardi 23 octobre 2018 - 14:36:07

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Nicolas Guillet, Alain Rives, René Lalauze, Christophe Pijolat. Study of adsorption of oxygen on -Al2O3 + Au and - Al2O3 + Pt: Work function measurements ; proposition of a model.. Applied Surface Science, Elsevier, 2003, 210 (3-4), pp.286-292. 〈10.1016/S0169-4332(02)01466-6〉. 〈emse-00431871〉

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