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Carbon dioxide and water incorporation mechanisms in SrFeO3−δ phases: a computational study

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journal contribution
posted on 09.11.2020, 11:54 by LJ Ford, PR Slater, Jamieson Christie, Pooja Goddard

With a higher propensity for low temperature synthesis routes along with a move toward lower solid oxide fuel cell operating temperatures, water and carbon dioxide incorporation in strontium ferrite is of importance. Despite this, the mechanisms are not well understood. In this work, classicalpotential-based computational techniques are used to determine the favourability of water and CO2 incorporation mechanisms in both SrFeO3−δ and SrFeO2.5. Our studies suggest that intrinsic Frenkel and Schottky type defects are unlikely to form, but that water and carbon dioxide incorporation are favourable in both phases. Water incorporation is likely for both the cubic and brownmillerite phases, with hydroxyl ions preferring to sit on octahedral oxygen sites in both structures, causing slight tilting of the shared octahedra. Interstitial hydroxyl ions are only likely for the brownmillerite phase, where the hydroxyl ions are most stable between adjacent FeO4 tetrahedral chains. Carbon dioxide incorporation via carbonate defects is most favourable when a carbonate molecule exists on an iron site, preferring the iron site with lower oxygen coordination. This involves formation of multiple oxygen vacancies surrounding the iron site, and thus we conclude that carbonate can trap oxygen vacancies.

Funding

EPSRC Centre for Doctoral Training in Fuel Cells and their Fuels - Clean Power for the 21st Century

Engineering and Physical Sciences Research Council

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Leverhulme Trust (Exploring carbonate incorporation in “oxide” materials: the hidden dopant in Materials Chemistry (RPG-2017-011)

ISCF Wave 1: (The JUICED Hub [Joint University Industry Consortium for Energy (Materials) and Devices Hub])

Engineering and Physical Sciences Research Council

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History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering
  • Science

Department

  • Chemistry
  • Materials

Published in

Physical Chemistry Chemical Physics

Publisher

Royal Society of Chemistry (RSC)

Version

VoR (Version of Record)

Rights holder

© The authors

Publisher statement

This is an Open Access Article. It is published by Royal Society of Chemistry (RSC) under the Creative Commons Attribution-NonCommercial 3.0 International Licence (CC BY-NC). Full details of this licence are available at: https://creativecommons.org/licenses/by-nc/3.0/

Acceptance date

12/10/2020

Publication date

2020-10-14

ISSN

1463-9076

eISSN

1463-9084

Language

en

Depositor

Dr Pooja Goddard Deposit date: 8 November 2020

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