This project is aimed at investigating the deactivation mechanisms in ceria supported noble metal catalysts closely related to the so-called Three Way Catalysts. It will be focused on the High Resolution Nanoanalytical study (EELS) of the catalysts based on (Rh,Pt) / CeLnxOy (Ln = Tb, La) under several treatments.
EELS experiments will be used to study the electronic Strong Metal-Support Interaction (SMSI) effect, the occurrence of Metal Decoration phenomena (partial covering of the noble metal crystallites by the reduced support), the formation of intermetallic compounds and direct chemical poisoning effects (presence of chlorine coming from the metal precursor). Supported Rhodium and Platinum from both chlorinated and unchlorinated metal precursors salts will be investigated. The reduction treatments will also be varied in a wide range of temperatures from 623 K to 1 173 K. The Project also considers the study of the chemical nature of the phases resulting from r2 treatment of M / CeO2. Mixed oxide formation (M/Ce) and rhodium and platinum oxidation degree will be studied.
Mixed oxide composition unhomogeneity and cation valence state mapping of fine structure will be obtained using EELS. This information will be very helpful to study the redox properties of this new generation of supports used for TWC's catalysts: the mixed oxide.
For a succesful development, this project requires the use of High Resolution Nanoanalytical facilities like those existing at the University Paris-Sud. The project would also take advantages of the highly reputated expertise of Dr. Colliex, who on the other hand, has personally been working on M / Rare Earth Oxide Catalysts Systems.
This Project would also allow the applicant to improve very significally his current background in nanoanalytical techniques, thus potentiating the consolidation at the University of Cadiz of a laboratory for Electron Microscopy Characterization of Catalysts, a major objective of our Research Group.