Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Crystal structure, cobalt and iron speciation and oxygen
  non-stoichiometry of La0.6Sr0.4Co1-yFeyO3-d nanorods for IT-SOFC cathodes   Single-phased La0.6Sr0.4Co1-yFeyO3-d (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 d for Co-rich samples. In addition, the values of d
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 degree of defects in nanomaterials and is probably one important factor in
the high electrochemical performance for the oxygen reduction reaction of
nanostructured La0.6Sr0.4Co1-yFeyO3-d IT-SOFC cathodes, which have been
reported in a previous work. Keywords: electrode materials; nanostructured
materials; X-ray diffraction; NEXAFS; M\"ossbauer spectroscopy

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The categories of this paper are: stat
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The categories of this paper are: econ
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The categories of this paper are: solv-int
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The categories of this paper are: eess
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The categories of this paper are: ao-sci
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The categories of this paper are: cmp-lg
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The categories of this paper are: cs
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The categories of this paper are: nlin
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The categories of this paper are: patt-sol
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The categories of this paper are: nucl-th
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The categories of this paper are: alg-geom
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The categories of this paper are: q-fin
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The categories of this paper are: gr-qc
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The categories of this paper are: dg-ga
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The categories of this paper are: chao-dyn
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The categories of this paper are: comp-gas