Isotopic exchange between the oxygen of a solid oxide electrolyte based on ZrO2 and gaseous oxygen

The rate of heteroexchange of oxygen of the electrolyte 0.906ZrO2 + 0.094Sc2O3 in an atmosphere of free oxygen at the temperature 700-8500C and oxygen pressure 10-40 mm Hg was measured by the method of isotopic exchange of oxygen using the isotope 18O. The rate of homoexchange of oxygen, the activation energies of the reactions of homo- and heteroexchange, the values of the orders of the dependence of the rates of these reactions on the oxygen pressure, as well as the contributions of various types of exchange to the total rate, were calculated. The characteristics of exchange obtained were compared with those for an electrolyte with composition 0.9ZrO2 + 0.1Y2O3. Reversible dissociative adsorption and desorption of oxygen is suggested as the limiting steps of heteroexchange