Oxygen vacancy ordering within anion-deficient Ceria
Journal article, 2009

The structural properties of anion deficient ceria, CeO2-delta, have been studied as a function of oxygen partial pressure, p(O-2), over the range 0 >= log(10)p(O-2) >= -18.9 at 1273(2) K using the neutron powder diffraction technique. Rietveld refinement of the diffraction data collected on decreasing p(O-2) showed increases in the cubic lattice parameter, a, the oxygen nonstoichiometry, delta, and the isotropic thermal vibration parameters, u(Ce) and u(O), starting at log(10)p(O-2)similar to-11. The increases are continuous, but show a distinct kink at log(10)p(O-2)similar to-14.5. Analysis of the total scattering (Bragg plus diffuse components) using reverse Monte Carlo (RMC) modelling indicates that the O2- vacancies preferentially align as pairs in the < 111 > cubic directions as the degree of nonstoichiometry increases. This behaviour is discussed with reference to the chemical crystallography of the CeO2-Ce2O3 system at ambient temperature and, in particular, to the nature of the long-range ordering of O2- vacancies within the crystal structure of Ce7O12. (C) 2009 Elsevier Inc. All rights reserved.

Nonstoichiometric Ceria

Electrical-Properties

Intermediate Phases

Oxide Fuel-Cell

Neutron-Diffraction

Ionic-Conductivity

Elevated-Temperatures

Defect Structure

System CeO2-Ce2O3

Author

Stephen Hull

ISIS Facility

Stefan Norberg

Chalmers, Chemical and Biological Engineering, Environmental Inorganic Chemistry

Istaq Ahmed

Chalmers, Chemical and Biological Engineering, Environmental Inorganic Chemistry

Sten Eriksson

Chalmers, Chemical and Biological Engineering, Environmental Inorganic Chemistry

Dario Marrocchelli

University of Edinburgh

Paul Madden

University of Edinburgh

University of Oxford

Journal of Solid State Chemistry

0022-4596 (ISSN) 1095-726X (eISSN)

Vol. 182 10 2815-2821

Subject Categories

Inorganic Chemistry

DOI

10.1016/j.jssc.2009.07.044

More information

Latest update

3/19/2018