Chemical surface exchange of oxygen on Y2O3-stabilized ZrO2

The chemical surface exchange of oxygen at single-crystalline Y2O3-stabilized ZrO2 surfaces is studied using the in situ optical absorption relaxation technique. The surface exchange coefficients depend on temperature, oxygen partial pressure, and redox-active dopant concentration in a dilute concentration range; they depend only slightly on surface orientation, and become independent of annealing time after a long time treatment (typically at 800 °C). Using the thermodynamic factor of oxygen (which sensitively depends on redox-active impurities) derived from the known defect chemical parameters of this material, the effective macroscopic chemical rate constants are analyzed. The correlation with effective tracer rate coefficients is discussed for this model electron-poor ionic conductor.