Crystal structure, cobalt and iron speciation and oxygen non-stoichiometry of La0.6Sr0.4Co1-yFeyO3-δ nanorods for IT-SOFC cathodes

JOURNAL OF ALLOYS AND COMPOUNDS

卷:817

Article

Mejia Gomez, Augusto E.¹  Sacanell, Joaquin^2,3  Huck-Iriart, Cristian⁴  Ramos, Cinthia P.^2,3  Soldati, Analia L.³  Figueroa, Santiago J. A.⁵  Tabacniks, Manfredo H.⁶  Fantini, Marcia C. A.⁶  Craievich, Aldo E.⁶  Lamas, Diego G.⁴ 

[1] Pontificia Univ Javeriana, Dept Fis, Grp Peliculas Delgadas & Nanofoton, Bogota, Colombia

[2] Comis Nacl Energia Atom, Dept Fis Mat Condensada, Ctr Atom Constituyentes, San Martin, Pcia De Buenos, Argentina

[3] CNEA CONICET, Inst Nanociencia & Nanotecnol, Buenos Aires, DF, Argentina

[4] Univ Nacl Gral San Martin, Lab Cristalog Aplicada, CONICET, Escuela Ciencia & Tecnol, San Martin, Pcia De Buenos, Argentina

[5] CNPEM, LNLS, BR-13083970 Campinas, SP, Brazil

[6] Univ Sao Paulo, Inst Fis, Sao Paulo, SP, Brazil

关键词: Electrode materials;    Nanostructured materials;    X-ray diffraction;    NEXAFS;    Mossbauer spectroscopy;   

DOI  :  10.1016/j.jallcom.2019.153250

来源: Elsevier

【 摘 要 】

Single-phased La(0.6)Sr(0.4)Co(1-)yFe(y)O(3-delta) (y = 0.2, 0.5, 0.8) nanorods exhibiting the rhombohedral perovskite-type phase were synthesized by a pore-wetting technique. We studied their chemical composition, crystal and electronic structures, morphology and hyperfine properties as a function of the Co/Fe content of the samples. Our results demonstrate that Co cations exhibit a slightly lower oxidation state than Fe ones, resulting in a higher oxygen non-stoichiometry delta for Co-rich samples. In addition, the values of delta determined in this work for nanostructured samples are much higher than those reported in the literature for bulk materials. This can be attributed to the high number of defects in nanomaterials and is probably one important factor in the high electrochemical performance for the oxygen reduction reaction of nanostructured La(0.6)Sr(0.4)Co(1-)yFe(y)O(3-delta) IT-SOFC cathodes, which have been reported in a previous work. (C) 2019 Elsevier B.V. All rights reserved.

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