resumo
A new oxide of the Ruddlesden-Popper series in the (Eu,Sr)(n+1)(Co,Fe)(n)O3n+1 system has been isolated and structurally characterized. X-ray diffraction and electron microscopy show that polycrystalline Eu2SrCo1.5Fe0.5O7 constitutes the n = 2 member of a homologous series, the essential feature of which is the existence of two connected Co/Fe octahedral layers with a perovskite-like structure, linked by an EuO rock-salt like layer. Random distributions of 3d-metals in the perovskite blocks and interstitial and oxygen vacancies in the rock-salt layers (anti Frenkel defects) are observed by electron microscopy. Such facts are commonly associated with high electronic conduction and ionic conductivity. The electrochemical study shows that the area-specific resistance of this compound is 0.26 cm(2) at 700 degrees C in air, a value which is comparable to those of the best state-of-the-art Ruddlesden-Popper materials used as cathodes in intermediate temperature solid oxide fuel cells.
palavras-chave
OXYGEN TRACER DIFFUSION; ELECTRICAL-CONDUCTIVITY; THERMAL-EXPANSION; ELECTROCHEMICAL CHARACTERIZATION; TRANSPORT-PROPERTIES; SEEBECK COEFFICIENT; CRYSTAL-STRUCTURE; AIR-ELECTRODES; PEROVSKITE; REDUCTION
categoria
Chemistry; Energy & Fuels; Materials Science
autores
Boulahya, K; Munoz-Gil, D; Gomez-Herrero, A; Azcondo, MT; Amador, U
nossos autores
Daniel Muñoz Gil
Bolseiro de pós-Doutoramentoagradecimentos
We thank Agencia Estatal de Investigacion (AEI)/Fondo Europeo de Desarrollo Regional (FEDER/UE) for funding the projects MAT2016-78362-C4-1-R and MAT2016-78362-C4-4-R, and ILL for financial support and facilitating access to the D2B diffractometer. The authors also thank Comunidad de Madrid and European Structural Funds for their financial support to the MATERYENER3-CM (S2013/MIT-2753) project. We thank Dr Manar Hassan for helping in sample preparation. Thanks to Dr Susana Garcia for fruitful discussions.