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http://hdl.handle.net/10773/19386
Title: | Thermochemical behavior and transport properties of Pr-substituted SrTiO3 as potential solid oxide fuel cell anode |
Author: | Yaremchenko, A. A. Patricio, S. G. Frade, J. R. |
Keywords: | NB-DOPED SRTIO3 STRONTIUM-TITANATE LOW-TEMPERATURES SOFC ANODES PRASEODYMIUM DIFFUSION CERAMICS SYSTEM DEFECT GAS |
Issue Date: | 2014 |
Publisher: | ELSEVIER SCIENCE BV |
Abstract: | Phase composition, structural stability, electrical properties, thermochemical expansion and redox behavior of Pr-substituted SrTiO3 were assessed for potential application in solid oxide fuel cell anodes. XRD analysis confirms formation of single-phase perovskite-like Sr1-xPrxTiO3 +/-delta and Sr1-1.5xPrxTiO3 +/-delta (x = 0.02-0.30) ceramics under both oxidizing and reducing conditions, although microstructural studies indicate minor precipitation of TiO2 in reduced Sr-deficient ceramics with high Pr content. XPS analysis in combination with XRD suggests that Pr cations substitute into strontium sublattice in mixed 4+/3+ oxidation state and are essentially insoluble in titanium sublattice. Reduction at elevated temperatures results in 2-3 orders of magnitude increase of n-type electronic conductivity with respect to oxidized materials. Thermogravimetric and electrical studies demonstrate however very slow reduction kinetics at temperatures below 1273 K associated with nearly frozen equilibrium in cation sublattice and low oxygen vacancy concentration in oxidized materials. Electrical behavior is discussed in conjunction with defect chemistry of donor-doped strontium titanate. All oxidized and reduced materials exhibit moderate thermal expansion coefficients, compatible with that of common solid electrolytes, and a small contribution of chemical expansion on reduction. (C) 2013 Elsevier B.V. All rights reserved. |
Peer review: | yes |
URI: | http://hdl.handle.net/10773/19386 |
DOI: | 10.1016/j.jpowsour.2013.07.019 |
ISSN: | 0378-7753 |
Publisher Version: | 10.1016/j.jpowsour.2013.07.019 |
Appears in Collections: | CICECO - Artigos |
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File | Description | Size | Format | |
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Thermochemical behavior and transport properties of Pr-substituted SrTiO3 as potential solid oxide fuel cell anode_10.1016j.jpowsour.2013.07.019.pdf | 2.6 MB | Adobe PDF |
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