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Microstructural characterization of lanthanide-doped ceria studied by XRD and TEM

Małgorzata Małecka ,  Leszek Kępiński 

Polish Academy of Sciences, Institute of Low Temperature and Structure Research (INTiBS), Okólna 2, Wrocław 50-422, Poland

Abstract

    Nanocrystalline lanthanide-doped ceria is an important material widely used in catalysis and SOFC technology. Chemical activity of ceria based oxides depend strongly on a kind amount of dopant, which determine also crystal structure and stability of the particles. For low and high dopant concentrations, structures of mixed oxides are more complicated. Addition of trivalent lanthanide ions to ceria (fluorite type structure) causes the oxygen-vacancies formation, which can be arranged in an ordered way to form superstructures.

    In this presentation, examples of various superstructures occuring in Ce1-xLnxO2-y oxides (Ln - trivalent lanthanide ion) will be presented. X-ray powder diffraction and transmission electron microscopy (together with electron diffraction) are very effective methods often used to characterize such materials. The basic structure of the mixed oxides for given composition can be characterized by powder X-ray diffraction, but superstructure reflections due to oxygen vacancy ordering are usualy very weak and are much easier detected in electron diffraction patterns. High resolution TEM provides additional direct information on the local ordering effects on the nanometer scale.

 

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Related papers

Presentation: Oral at 11th European Powder Diffraction Conference, Microsymposium 8, by Małgorzata Małecka
See On-line Journal of 11th European Powder Diffraction Conference

Submitted: 2008-04-15 16:57
Revised:   2009-06-07 00:48