In situ X-ray and neutron diffraction of the Ruddlesden–Popper compounds (RE2–xSrx)₀.₉₈(Fe₀.₈Co₀.₂)1–yMgyO4–δ (RE=La, Pr): Structure and CO₂ stability
- Institute for Energy Technology, P.O. Box 40, Kjeller NO-2027 (Norway)
- Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, DK-4000 Roskilde (Denmark)
The crystal structure of the Ruddlesden–Popper compounds (La₁.₀Sr₁.₀)₀.₈Fe₁.₀Co₀.₂O4–δ and (La₁.₂Sr₀.₈)₀.₉₈(Fe₀.₈Co₀.₂)₀.₈Mg₀.₂O4–δ was investigated at 1000 °C in N₂ (aO₂=1×10₋₄ by in-situ powder neutron diffraction. In-situ powder X-ray diffraction (PXD) was also employed to investigate the temperature dependence of the lattice parameters of the compounds in air and the oxygen activity dependence of the lattice parameters at 800 °C and 1000 °C. The thermal and chemical expansion coefficients, determined along the two crystallographic directions of the tetragonal unit cell, are highly anisotropic. The equivalent pseudo-cubic thermal and chemical expansion coefficients are in agreement with values determined by dilatometry. The chemical stability in CO₂ containing environments of various Ruddlesden–Popper compounds with chemical formula (RE2-xSrx)₀.₉₈(Fe₀.₈Co₀.₂)1-yMgyO4–δ (RE=La, Pr), as well as their stability limit in H₂/H₂O=4.5 were also determined by in-situ PXD for x=0.9, 1.0 and y=0, 0.2. - Graphical abstract: Influence of electronic configuration on bond length, lattice parameters and anisotropic thermal and chemical expansion. Highlights: • The thermal and chemical expansion coefficients are largely anisotropic. • The expansion of the perovskite layers is constrained along the a direction. • The studied compositions show remarkable thermodynamic stability upon reduction. • The thermal and chemical expansion coefficients are lower than related perovskites. • The investigated materials decompose in CO₂ containing atmospheres.
- OSTI ID:
- 22306281
- Journal Information:
- Journal of Solid State Chemistry, Vol. 201; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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