Defect equilibrium in PrBaCo{sub 2}O{sub 5+δ} at elevated temperatures
- Institute of Solid State Chemistry, Pervomaiskaya str.91, Ekaterinburg 620990 (Russian Federation)
A defect equilibrium model for PrBaCo{sub 2}O{sub 5+δ} is suggested based on oxygen non-stoichiometry data. The model includes reactions of oxygen exchange and charge disproportionation of Co{sup 3+} cations. The respective equilibrium constants, enthalpies and entropies for the reactions entering the model are obtained from the fitting of the experimental data for oxygen non-stoichiometry. The enthalpies of oxidation Co{sup 2+}→Co{sup 3+} and Co{sup 3+}→Co{sup 4+} are found to be equal to 115±9 kJ mol{sup –1} and 45±4 kJ mol{sup –1}, respectively. The obtained equilibrium constants were used in order to calculate variations in concentration of cobalt species with non-stoichiometry, temperature and oxygen pressure. - Graphical abstract: Variations in concentration of cobalt species with oxygen content in PrBaCo{sub n}{sup 2+}Co{sub z}{sup 3+}Co{sub p}{sup 4+}O{sub 5+δ} at 650 °S. Display Omitted - Highlights: • The defect equilibrium model based on oxygen non-stoichiometry data is suggested. • Disproportionation of Co{sup 3+} cations gives significant contribution to defect equilibrium. • The hole concentration obtained from the model is in accord with electrical properties.
- OSTI ID:
- 22274110
- Journal Information:
- Journal of Solid State Chemistry, Vol. 206; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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