Ceria-zirconia nanoparticles doped with La or Gd: effect of the doping cation on the real structure

Vladislav A. Sadykov 1Vladimir V. Kriventsov 1Ella M. Moroz 1Yulia V. Borchert 2Dmitrii A. Zyuzin 1Vera P. Kolko 1Tatyana G. Kuznetsova 1Vyacheslav P. Ivanov 1Andrei I. Boronin 1Natalia V. Mezentseva 1Elena B. Burgina 1Julian Ross 3

1. Boreskov Institute of Catalysis (BIC), pr. akad. Lavrentieva, 5, Novosibirsk 630090, Russian Federation
2. University of Bremen, Otto-Hahn-Allee, Bremen 28359, Germany
3. University of Limerick (UL), Plassey Technological Park, Limerick 02098, Ireland

Abstract

This work presents results of studies of the real structure of nanocrystalline CeO2-ZrO2 (Ce:Zr=1:1) systems prepared via Pechini route and doped with La3+ or Gd3+ cations (x up to 30 at.%). X-ray diffraction, EXAFS, UV-Vis and Raman spectroscopy were applied for the bulk characterization, while the surface features were studied by XPS and SIMS. For both systems, the increase of Ln3+ content was accompanied by the decline of domain size and increase of the specific surface area and lattice parameter of fluorite-like phases. While for bigger La3+ the system becomes bi-phasic at xLa > 10 at.%, for smaller Gd3+ cation single-phase solid solution exists within all studied range. For both systems, depletion of the surface layer by smaller Zr4+ cations was revealed, while the surface content of a doping cation is either close to that in the bulk (La) or lower (Gd). Such a spatial distribution of components results in some ordering of cations within the particle. It is reflected in different modes of rearrangement of oxygen coordination polyhedra with the Gd or La content (by EXAFS), and redistribution of the intensity of reflections in XRD patterns not conforming to a simple model with statistical distribution of oxygen vacancies. Associated variation of average Ce(Zr)-O bond strength (SIMS) appears to affect the lattice oxygen mobility. This work is in part supported by INTAS 05-1000005-7663, RFBR-CNRS 05-03-34761 Projects and Integration Project 4.15 SB RAS.

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Presentation: Oral at E-MRS Fall Meeting 2006, Symposium C, by Vladislav A. Sadykov
See On-line Journal of E-MRS Fall Meeting 2006

Submitted: 2006-05-14 15:53
Revised:   2009-06-07 00:44
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