The model catalysts of ZrO2-supported Au nanoparticles have been prepared by deposition of Au atoms onto the surfaces of thin ZrO2 films with different morphologies. The adsorption and thermal stability of Au nanopartides on thin ZrO2 films have been investigated using synchrotron radiation photoemission spectroscopy (SRPES) and X-ray photoelectron spectroscopy (XPS). The thin ZrO2 films were prepared by two different methods, giving rise to different morphologies. The first method utilized wet chemical impregnation to synthesize the thin ZrO2 film through the procedure of first spin-coating a zirconium ethoxide (Zr(OC2H5)(4)) precursor onto a SiO2/Si(100) substrate at room temperature followed by calcination at 773 K for 12 h. Scanning electron microscopy (SEM) investigations indicate that highly porous "sponge-like nanostructures" were obtained in this case. The second method was epitaxial growth of a ZrO2(111) film through vacuum evaporation of Zr metal onto Pt(111) in 1 x 10(-6) Torr of oxygen at 550 K followed by annealing at 1000 K. The structural analysis with low energy electron diffraction (LEED) of this film exhibits good long-range ordering. It has been found that Au forms smaller particles on the porous ZrO2 film as compared to those on the ordered ZrO2(111) film at a given coverage. Thermal annealing experiments demonstrate that Au particles are more thermally stable on the porous ZrO2 surface than on the ZrO2(111) surface, although on both surfaces, Au particles experience significant sintering at elevated temperatures. In addition, by annealing the surfaces to 1100 K, Au particles desorb completely from ZrO2(111) but not from porous ZrO2. The enhanced thermal stability for Au on porous ZrO2 can be attributed to the stronger interaction of the adsorbed Au with the defects and the hindered migration or coalescence resulting from the porous structures.