Defect Chemistry and Thermomechanical Properties of Ce0.8PrxTb0.2-xO2-delta

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    Abstract

    The oxygen nonstoichiometry (delta) of Ce0.8PrxTb0.2-xO2-delta (x=0, 0.05, 0.10, 0.15, 0.20) was measured as a function of P-O2 at temperatures between 600 and 900 degrees C by coulometric titration and thermogravimetry. A nonideal solution model, allowing for a linear delta dependence of the partial molar enthalpy of reduction in the dopants, could successfully reproduce the experimentally determined oxygen nonstoichiometry. X-ray absorption near-edge spectroscopy measurements were performed at the Ce/Pr/Tb L3 and L2 edges. The valence state of each dopant was affected by the presence of the co-dopant. The redox properties strongly depended on the lattice strain energy and the mean metal-oxygen bond strength. The thermal and chemical expansion coefficients were determined by dilatometry. The strongly nonlinear behavior of the thermal expansion coefficient originated from the chemical strain due to increasing oxygen nonstoichiometry with increasing temperature.
    Original languageEnglish
    JournalJournal of The Electrochemical Society
    Volume157
    Issue number2
    Pages (from-to)B299-B307
    ISSN0013-4651
    DOIs
    Publication statusPublished - 2010

    Bibliographical note

    Copyright The Electrochemical Society, Inc. [2010]. All rights reserved. Except as provided under U.S. copyright law, this work may not be reproduced, resold, distributed, or modified without the express permission of The Electrochemical Society (ECS).

    Keywords

    • Solid Oxide Fuel Cells
    • Fuel Cells and hydrogen

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