Oxidation states of the transition metal cations in the highly nonstoichiometric perovskite-type oxide Ba0.1Sr0.9Co0.8Fe0.2O3−δ

David N. Mueller; Roger A. De Souza; Jochen Brendt; Dominik Samuelis; Manfred Martin

doi:10.1039/B819415G

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Oxidation states of the transition metal cations in the highly nonstoichiometric perovskite-type oxide Ba_0.1Sr_0.9Co_0.8Fe_0.2O_3−δ†

David N. Mueller,^a Roger A. De Souza,*^a Jochen Brendt,^a Dominik Samuelis ‡^a and Manfred Martin^a

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* Corresponding authors

^a Institute of Physical Chemistry, RWTH Aachen University, Aachen, Germany
E-mail: desouza@pc.rwth-aachen.de
Tel: +49 241 80 94739

Abstract

The oxidation states of Fe and Co in the complex perovskite-type oxide Ba_0.1Sr_0.9Co_0.8Fe_0.2O_3−δ were determined by means of X-ray absorption near edge structure (XANES) spectroscopy. Measurements performed in situ for 783 ≤ T/K ≤ 918 and 50 ≤ pO₂/Pa ≤ 2 × 10⁴ reveal that the electrons generated by reduction are not equally distributed between the Fe and Co cations. A comparison with thermogravimetric measurements indicates a discrepancy in the amount of oxygen lost from the sample. This discrepancy is an indication that not only are the transition metal cations reduced but the oxygen anions are, too. A model explaining the observed behaviour is proposed.

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Supplementary files

Details of sample preparation, thermogravimetric analysis(TGA) and X-ray absorption spectroscopy (XAS) experiments,including beamline setup and energy calibration PDF (326K)

Article information

DOI: https://doi.org/10.1039/B819415G
Article type: Communication
Submitted: 31 Oct 2008
Accepted: 11 Feb 2009
First published: 23 Feb 2009

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J. Mater. Chem., 2009,19, 1960-1963

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Oxidation states of the transition metal cations in the highly nonstoichiometric perovskite-type oxide Ba_0.1Sr_0.9Co_0.8Fe_0.2O_3−δ

D. N. Mueller, R. A. De Souza, J. Brendt, D. Samuelis and M. Martin, J. Mater. Chem., 2009, 19, 1960 DOI: 10.1039/B819415G

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