Ultra-Thin CeO2 Overlayer on YSZ Studied by X-Ray Surface Scattering
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Biochemical and Biomolecular Engineering
Catalysis and Reaction Engineering
Ceramic Materials
Chemical Engineering
Engineering
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Transition metal catalysts such as Rh/Pt used in a three-way automotive catalytic converter have to perform reduction and oxidation functions at the same time. This can be accomplished only in a specific range of oxygen pressure and temperature. In order to maintain a constant partial pressure of oxygen in the vicinity of catalysts mixtures of ceria and zirconia are used. Ceria is an essential component due to its capability of storing oxygen under oxidizing and releasing oxygen under reducing conditions. However, this function deteriorates with time and eventually a catalytic converter stops working properly. It is not well understood why this particular mixture of oxides can achieve the role as a oxygen buffer and why its lifetime is limited. In order to address this issue and to understand the structural interplay at the ceria/zirconia interface, we studied the atomic structure of ultra-thin ceria layers deposited on single crystals of (001) oriented Y-stabilized zirconia (YSZ), in situ, during annealing in air using the synchrotron x-ray surface diffraction technique.