Physicochemical characterization of Au/CeO2 solid. Part 1: The deposition–precipitation preparation method

Au/CeO2 (4 wt.% gold) solid was prepared using the deposition–precipitation method. The deposition of gold on ceria did not affect its specific surface area (122 m2 g−1/400 °C). The average diameter of gold particles obtained was estimated to be equal to 3.9 nm. Moreover, 60% of the gold was in the form of nanoparticles with a size ranging between 3 and 4 nm. 80% of the gold in the nanoparticles was in the metallic form Au0 and 20% was present as Au+. These latter cations interact directly with the image anions of CeO2. When evacuated at 400 °C for 1 h, the cations were reduced into Au0. All the adsorptions were performed on solids treated under vacuum at 400 °C for 1 h. The adsorption of O2 at room temperature led to the formation of image species. The adsorption of 17O-enriched molecular oxygen demonstrated that the two oxygen atoms in image are equivalent. When CO was introduced, it reacted with the image of the support to give image. When NO2, NO or N2O were added at room temperature, they decomposed to form adsorbed image species at the surface of the solid.