XPS study of Pt/CexZr1-xO2/Si composite systems
Abstract
This work describes the study of a surface reduction of ceria zirconia mixed oxides (CeZrO) as either thin films or powders, both with and without Pt present. XPS was used to measure the composition of the surface and the oxidation states of all metals contained within the material. The thin film of CeZrO showed little reactivity towards the reducing conditions used. The size of the Pt clusters was also determined from the data. The Pt was found to always exist in the metallic state. The Zr4+ was not seen to change during all treatments. For the powder samples the CE4+ was readily reduced to approximately 60%. Pt was found to be initially oxidised with the % of metallic Pt increasing with reduction temperature. Again no change in the Zr was observed.