A mixed conductor, ZrO2-CeO2-Y2O3 (Ce-YSZ), exhibits anomalous electrical p
roperties depending on oxygen partial pressure and CeO2 concentration. We m
easured surface reaction rates and oxygen tracer diffusion coefficients of
YSZ with various CeO2 concentrations by secondary ion mass analyses. The Ce
concentration dependence of oxygen tracer diffusion coefficient in air cor
responds with that of the total electrical conductivity, over which the ion
ic conductivity is dominant. The surface exchange coefficient, however, had
a higher value in the region of 20 similar to 60 mol% CeO2 containing YSZ
compared to other compositions. Ce-YSZ, which contains this region of CeO2
concentration, exhibits high electronic conduction at reducing conditions.
The ionic and electronic conductivities are considered to affect the oxygen
tracer diffusion coefficient and the surface exchange coefficient, respect
ively. (C) 2000 Elsevier Science B.V. All rights reserved.