Structure and thermal stability of ceria films supported on YSZ(1 0 0) and α-Al2O3(0 0 0 1)

The morphology and reducibility of vapor-deposited ceria films supported on yttria-stabilized zirconia (1 0 0) (YSZ(1 0 0)) and α-Al2O3(0 0 0 1) single crystals were studied using X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The results of this study show that the gas environment has a significant effect on the structure of the ceria films on both substrates. CeO2 films on α-Al2O3(0 0 0 1) were found to be stable in a reducing environment at temperatures up to 1000 K, but underwent agglomeration and reaction with the support to form CeAlO3 upon annealing at 1273 K in air. Heating CeO2/YSZ(1 0 0) in air at 1273 K caused the ceria thin film to agglomerate into bar-shaped features which were re-dispersed by subsequent annealing in vacuum. Interactions at the CeO2–YSZ interface were also found to dramatically enhance the reducibility of ceria films supported on YSZ(1 0 0).