Structure, electrical conductivity and oxygen transport properties of perovskite-type oxides CaMn1−x−yTixFeyO3−δ

R. Ruhl, J. Song, V. Thoréton, S.P. Singh, K. Wiik, Y. Larring, Henny Bouwmeester* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Calcium manganite-based perovskite-type oxides hold promise for application in chemical looping combustion processes and oxygen transport membranes. In this study, we have investigated the structure, electrical conductivity and oxygen transport properties of perovskite-type oxides CaMn1 x yTixFeyO3-δ. Distinct from previous work, data of high-temperature X-ray diffraction (HT-XRD) in the temperature range 600-1000 °C (with intervals of 25 °C) demonstrates that CaMnO3-δ (CM) transforms from orthorhombic to a mixture of orthorhombic and tetragonal phases between 875°C and 900 °C. The Rietveld refinements show formation of a pure tetragonal phase at 975 °C and of a pure cubic phase at 1000 °C. Partial substitution of manganese by iron and/or titanium to yield CaMn0.875Ti0.125O3-δ (CMT), CaMn0.85Fe0.15O3-δ (CMF) or CaMn0.725Ti0.125Fe0.15O3-δ (CMTF) leads to different phase behaviours. While CMT remains orthorhombic up to the highest temperature covered by the HT-XRD experiments, CMF and CMTF undergo an orthorhombic □(→) tetragonal □(→) cubic sequence of phase transitions. Electrical conductivity relaxation measurements are conducted to determine the chemical diffusion coefficient (Dchem) and the surface exchange coefficient (kchem) of the materials. The results demonstrate that oxygen transport is hindered in the tetragonal phase, when occurring, which is attributed to a possible ordering of oxygen vacancies. The small polaron electrical conductivity of CM in the cited temperature range is lowered upon partial manganese substitution, by about 10% for CMF and up to half an order of magnitude for CMT and CMTF.
Original languageEnglish
Pages (from-to)21824-21835
Number of pages12
JournalPhysical chemistry chemical physics
Volume21
Issue number39
Early online date18 Sep 2019
DOIs
Publication statusPublished - 21 Oct 2019

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Transport properties
Oxides
transport properties
Oxygen
electrical resistivity
oxides
oxygen
manganese
Manganese
substitutes
Substitution reactions
Temperature
X ray diffraction
Gene Conversion
diffraction
Rietveld refinement
calcium
Oxygen vacancies
Phase behavior
Titanium

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Ruhl, R. ; Song, J. ; Thoréton, V. ; Singh, S.P. ; Wiik, K. ; Larring, Y. ; Bouwmeester, Henny. / Structure, electrical conductivity and oxygen transport properties of perovskite-type oxides CaMn1−x−yTixFeyO3−δ. In: Physical chemistry chemical physics. 2019 ; Vol. 21, No. 39. pp. 21824-21835.
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title = "Structure, electrical conductivity and oxygen transport properties of perovskite-type oxides CaMn1−x−yTixFeyO3−δ",
abstract = "Calcium manganite-based perovskite-type oxides hold promise for application in chemical looping combustion processes and oxygen transport membranes. In this study, we have investigated the structure, electrical conductivity and oxygen transport properties of perovskite-type oxides CaMn1 x yTixFeyO3-δ. Distinct from previous work, data of high-temperature X-ray diffraction (HT-XRD) in the temperature range 600-1000 °C (with intervals of 25 °C) demonstrates that CaMnO3-δ (CM) transforms from orthorhombic to a mixture of orthorhombic and tetragonal phases between 875°C and 900 °C. The Rietveld refinements show formation of a pure tetragonal phase at 975 °C and of a pure cubic phase at 1000 °C. Partial substitution of manganese by iron and/or titanium to yield CaMn0.875Ti0.125O3-δ (CMT), CaMn0.85Fe0.15O3-δ (CMF) or CaMn0.725Ti0.125Fe0.15O3-δ (CMTF) leads to different phase behaviours. While CMT remains orthorhombic up to the highest temperature covered by the HT-XRD experiments, CMF and CMTF undergo an orthorhombic □(→) tetragonal □(→) cubic sequence of phase transitions. Electrical conductivity relaxation measurements are conducted to determine the chemical diffusion coefficient (Dchem) and the surface exchange coefficient (kchem) of the materials. The results demonstrate that oxygen transport is hindered in the tetragonal phase, when occurring, which is attributed to a possible ordering of oxygen vacancies. The small polaron electrical conductivity of CM in the cited temperature range is lowered upon partial manganese substitution, by about 10{\%} for CMF and up to half an order of magnitude for CMT and CMTF.",
author = "R. Ruhl and J. Song and V. Thor{\'e}ton and S.P. Singh and K. Wiik and Y. Larring and Henny Bouwmeester",
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month = "10",
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doi = "10.1039/c9cp04911h",
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Structure, electrical conductivity and oxygen transport properties of perovskite-type oxides CaMn1−x−yTixFeyO3−δ. / Ruhl, R.; Song, J.; Thoréton, V.; Singh, S.P.; Wiik, K.; Larring, Y.; Bouwmeester, Henny (Corresponding Author).

In: Physical chemistry chemical physics, Vol. 21, No. 39, 21.10.2019, p. 21824-21835.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Structure, electrical conductivity and oxygen transport properties of perovskite-type oxides CaMn1−x−yTixFeyO3−δ

AU - Ruhl, R.

AU - Song, J.

AU - Thoréton, V.

AU - Singh, S.P.

AU - Wiik, K.

AU - Larring, Y.

AU - Bouwmeester, Henny

PY - 2019/10/21

Y1 - 2019/10/21

N2 - Calcium manganite-based perovskite-type oxides hold promise for application in chemical looping combustion processes and oxygen transport membranes. In this study, we have investigated the structure, electrical conductivity and oxygen transport properties of perovskite-type oxides CaMn1 x yTixFeyO3-δ. Distinct from previous work, data of high-temperature X-ray diffraction (HT-XRD) in the temperature range 600-1000 °C (with intervals of 25 °C) demonstrates that CaMnO3-δ (CM) transforms from orthorhombic to a mixture of orthorhombic and tetragonal phases between 875°C and 900 °C. The Rietveld refinements show formation of a pure tetragonal phase at 975 °C and of a pure cubic phase at 1000 °C. Partial substitution of manganese by iron and/or titanium to yield CaMn0.875Ti0.125O3-δ (CMT), CaMn0.85Fe0.15O3-δ (CMF) or CaMn0.725Ti0.125Fe0.15O3-δ (CMTF) leads to different phase behaviours. While CMT remains orthorhombic up to the highest temperature covered by the HT-XRD experiments, CMF and CMTF undergo an orthorhombic □(→) tetragonal □(→) cubic sequence of phase transitions. Electrical conductivity relaxation measurements are conducted to determine the chemical diffusion coefficient (Dchem) and the surface exchange coefficient (kchem) of the materials. The results demonstrate that oxygen transport is hindered in the tetragonal phase, when occurring, which is attributed to a possible ordering of oxygen vacancies. The small polaron electrical conductivity of CM in the cited temperature range is lowered upon partial manganese substitution, by about 10% for CMF and up to half an order of magnitude for CMT and CMTF.

AB - Calcium manganite-based perovskite-type oxides hold promise for application in chemical looping combustion processes and oxygen transport membranes. In this study, we have investigated the structure, electrical conductivity and oxygen transport properties of perovskite-type oxides CaMn1 x yTixFeyO3-δ. Distinct from previous work, data of high-temperature X-ray diffraction (HT-XRD) in the temperature range 600-1000 °C (with intervals of 25 °C) demonstrates that CaMnO3-δ (CM) transforms from orthorhombic to a mixture of orthorhombic and tetragonal phases between 875°C and 900 °C. The Rietveld refinements show formation of a pure tetragonal phase at 975 °C and of a pure cubic phase at 1000 °C. Partial substitution of manganese by iron and/or titanium to yield CaMn0.875Ti0.125O3-δ (CMT), CaMn0.85Fe0.15O3-δ (CMF) or CaMn0.725Ti0.125Fe0.15O3-δ (CMTF) leads to different phase behaviours. While CMT remains orthorhombic up to the highest temperature covered by the HT-XRD experiments, CMF and CMTF undergo an orthorhombic □(→) tetragonal □(→) cubic sequence of phase transitions. Electrical conductivity relaxation measurements are conducted to determine the chemical diffusion coefficient (Dchem) and the surface exchange coefficient (kchem) of the materials. The results demonstrate that oxygen transport is hindered in the tetragonal phase, when occurring, which is attributed to a possible ordering of oxygen vacancies. The small polaron electrical conductivity of CM in the cited temperature range is lowered upon partial manganese substitution, by about 10% for CMF and up to half an order of magnitude for CMT and CMTF.

U2 - 10.1039/c9cp04911h

DO - 10.1039/c9cp04911h

M3 - Article

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EP - 21835

JO - Physical chemistry chemical physics

JF - Physical chemistry chemical physics

SN - 1463-9076

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