HOMOMOLECULAR OXYGEN-EXCHANGE IN THE SYSTEMS - O2/PT AND O2, PT/SOLID OXIDE ELECTROLYTE

Homomolecular oxygen exchange was studied at surfaces of platinum foil and wire, as well as in the systems Pt/0.8 Bi2O3 + 0.2 Er2O3, Pt/0.7 CeO2 + 0.3 LaO1.5, and Pt/0.9 ZrO2 + 0.1 Y2O3 at temperatures of 760 to 1140 K and oxygen pressures of 400 to 3550 Pa. The exchange rates, activation energies of the homoexchange reactions, and reaction order with respect to oxygen were found. The decisive importance of the platinum surface in oxygen homoexchange was established for the electrode systems with electrolytes on the basis of zirconium dioxide and cerium dioxide when the exchange rates, activation energies, and reaction orders were compared between the Pt/electrolyte systems and the individual components of these systems. In the electrode system with an electrolyte on the basis of bismuth oxide, it is the oxide surface which is more important, even though the influence of the platinum surface increases when more platinum is deposited.