Anomalous transport property at surface and interface of metal/rare earth doped ceria

The oxygen transport around gold/oxide ion conducting oxides such as gadolinium doped ceria (GDC) and yttria stabilized zirconia (YSZ) was investigated by using oxygen isotope exchange and secondary ion mass spectrometry (SIMS). The active area of oxygen exchange was clearly observed in the vicinity of Au/YSZ/O2 triple phase boundary at T = 973 K in dry O2 condition. On the other hand, the activation of oxygen exchange was broadly observed around Au/GDC interface treated at the same condition. Although the hole conductivity of GDC is considered to be much higher than that of YSZ, it does not significantly enhance the oxygen exchange at the GDC surface. The chemical inhomogeneity on the GDC surface is considered to be one of the factors which may suppress oxygen exchange.