Characterization of GdBa1 − xSrxCo2O5 + δ ( 0 ⩽ x ⩽ 1.0 ) Double Perovskites as Cathodes for Solid Oxide Fuel Cells
The effect of Sr2+ substitution for Ba2+ on the crystal chemistry, oxygen content, thermal expansion, electrical conductivity, and catalytic activity for oxygen reduction reaction (ORR) of the double perovskite oxides Gd Ba1-x Srx Co2 O5+δ has been investigated for 0≤x≤1.0. The Gd Ba1-x Srx Co2 O5+δ...
| Autores: | , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2008 |
| País: | Argentina |
| Institución: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositorio: | CONICET Digital (CONICET) |
| Idioma: | inglés |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/71358 |
| Acceso en línea: | http://hdl.handle.net/11336/71358 |
| Access Level: | acceso abierto |
| Palabra clave: | https://purl.org/becyt/ford/1.4 https://purl.org/becyt/ford/1 |
| Sumario: | The effect of Sr2+ substitution for Ba2+ on the crystal chemistry, oxygen content, thermal expansion, electrical conductivity, and catalytic activity for oxygen reduction reaction (ORR) of the double perovskite oxides Gd Ba1-x Srx Co2 O5+δ has been investigated for 0≤x≤1.0. The Gd Ba1-x Srx Co2 O5+δ system exhibits a structural change from orthorhombic (x=0) to tetragonal (0.2≤x≤0.6) to orthorhombic (x=1) with increasing Sr content. The difference in ionic radii between (Ba1-x Srx)2+ and Gd3+ plays a dominant role in determining the oxygen-content value in Gd Ba1-x Srx Co2 O5+δ, and the oxygen content and the oxidation state of cobalt increase with increasing Sr content. The electrical conductivity of the Gd Ba1-x Srx Co2 O5+δ system increases with Sr content due to an increasing oxygen content and a straightening of the O-Co-O bonds as evidenced by the structural change from orthorhombic to tetragonal. Sr substitution also improves the chemical stability of the Gd Ba1-x Srx Co2 O5+δ cathodes in contact with the Ce0.9 Gd0.1 O1.95 and La0.8 Sr0.2 Ga0.8 Mg0.2 O2.8 electrolytes at 1100°C. The x=0.2 and 0.6 samples with a tetragonal structure exhibit higher catalytic activity for ORR in single-cell solid oxide fuel cell than the x=0 and 1.0 samples with an orthorhombic structure. |
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