Effect of oxygen diffusion path radii on the oxygen intake/release properties of Brownmillerite SrCoO 2.5

Narayanan, AM and Umarji, AM (2021) Effect of oxygen diffusion path radii on the oxygen intake/release properties of Brownmillerite SrCoO 2.5. In: Chemical Papers, 75 (7). pp. 3241-3251.

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Abstract

Abstract: Chemical modification has been proved to be an effective way to tune various material properties. Herein, the oxygen intake/release properties of substituted Sr1-xMxCoO2.5 (M = Ca, Ba, x = 0.02 (2 at. %), 0.05 (5 at. %), 0.1 (10 at. %), and 0.2 (20 at. %)) are explored. The substitution range was limited to the stability range of the brownmillerite structure. Phase purity and the unit cell expansion/contraction by substitution were confirmed by X-ray diffraction. The oxygen intake/release of the substituted samples was characterized by a custom-built volumetric apparatus and iodometric titration. Thermal expansion coefficient and electrical conductivity measurements were carried out on substituted samples. The reversible oxygen intake/release was found to decrease with both Ba and Ca substitution, even though a reduction in activation energy by Ba substitution was observed. This is correlated with an increased bond dissociation energy and a drastic decrease in critical radius of the bottle neck through which oxide ion migration occurs, especially with Ba substitution. Graphic abstract : [Figure not available: see fulltext.]

Item Type:	Journal Article
Publication:	Chemical Papers
Publisher:	Springer Science and Business Media Deutschland GmbH
Additional Information:	The copyright for this article belongs to the Springer Science and Business Media Deutschland GmbH.
Keywords:	Brownmillerite; Mixed ion electron conductor; Oxygen non-stoichiometry; Perovskite oxide
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	28 Nov 2023 05:24
Last Modified:	28 Nov 2023 05:24
URI:	https://eprints.iisc.ac.in/id/eprint/82961

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