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Structural and microstructural changes during anion exchange of CoAl layered double hydroxides: an in situ X-ray powder diffraction study. / Johnsen, Rune; Krumeich, Frank; Norby, Poul.

In: Journal of Applied Crystallography, Vol. 43, No. 3, 2010, p. 434-447.

Publication: Research - peer-reviewJournal article – Annual report year: 2010

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Johnsen, Rune; Krumeich, Frank; Norby, Poul / Structural and microstructural changes during anion exchange of CoAl layered double hydroxides: an in situ X-ray powder diffraction study.

In: Journal of Applied Crystallography, Vol. 43, No. 3, 2010, p. 434-447.

Publication: Research - peer-reviewJournal article – Annual report year: 2010

Bibtex

@article{1bf8ebfce08e4b888e7937cb61ece3c9,
title = "Structural and microstructural changes during anion exchange of CoAl layered double hydroxides: an in situ X-ray powder diffraction study",
publisher = "Wiley-Blackwell Munksgaard",
author = "Rune Johnsen and Frank Krumeich and Poul Norby",
year = "2010",
doi = "10.1107/S0021889810011805",
volume = "43",
number = "3",
pages = "434--447",
journal = "Journal of Applied Crystallography",
issn = "0021-8898",

}

RIS

TY - JOUR

T1 - Structural and microstructural changes during anion exchange of CoAl layered double hydroxides: an in situ X-ray powder diffraction study

A1 - Johnsen,Rune

A1 - Krumeich,Frank

A1 - Norby,Poul

AU - Johnsen,Rune

AU - Krumeich,Frank

AU - Norby,Poul

PB - Wiley-Blackwell Munksgaard

PY - 2010

Y1 - 2010

N2 - Anion-exchange processes in cobalt-aluminium layered double hydroxides (LDHs) were studied by in situ synchrotron X-ray powder diffraction (XRPD). The processes investigated were CoAl-CO3 CoAl-Cl CoAl-CO3, CoAl-Cl CoAl-NO3 and CoAl-CO3 CoAl-SO4. The XRPD data show that the CoAl-CO3 CoAl-Cl process is a two-phase transformation, where the amount of the CoAl-CO3 phase decreases exponentially while that of the CoAl-Cl phase increases exponentially. Energy-dispersive X-ray spectroscopy (EDXS) studies of a partially chloride-exchanged CoAl-CO3 LDH sample along with in situ XRPD data suggested that the individual particles in the CoAl-CO3 sample are generally anion-exchanged with chloride one at a time. In contrast with the CoAl-CO3 CoAl-Cl transformation, the XRPD data show that the reverse CoAl-Cl CoAl-CO3 process is a one-phase transformation. Rietveld refinements indicate that the occupancy factors of the carbon and oxygen sites of the carbonate group increase, while that of the chloride site decreases. In the CoAl-Cl CoAl-NO3 anion-exchange reaction, the XRPD patterns reveal the existence of two intermediate phases in addition to the initial CoAl-Cl and final CoAl-NO3 phases. The in situ data indicate that one of these intermediates is a mixed nitrate- and chloride-based LDH phase, where the disorder decreases as the nitrate content increases. The XRPD data of the partial CoAl-CO3 CoAl-SO4 anion-exchange reaction show that the process is a two-phase transformation involving a sulfate-containing LDH with a 1H polytype structure.

AB - Anion-exchange processes in cobalt-aluminium layered double hydroxides (LDHs) were studied by in situ synchrotron X-ray powder diffraction (XRPD). The processes investigated were CoAl-CO3 CoAl-Cl CoAl-CO3, CoAl-Cl CoAl-NO3 and CoAl-CO3 CoAl-SO4. The XRPD data show that the CoAl-CO3 CoAl-Cl process is a two-phase transformation, where the amount of the CoAl-CO3 phase decreases exponentially while that of the CoAl-Cl phase increases exponentially. Energy-dispersive X-ray spectroscopy (EDXS) studies of a partially chloride-exchanged CoAl-CO3 LDH sample along with in situ XRPD data suggested that the individual particles in the CoAl-CO3 sample are generally anion-exchanged with chloride one at a time. In contrast with the CoAl-CO3 CoAl-Cl transformation, the XRPD data show that the reverse CoAl-Cl CoAl-CO3 process is a one-phase transformation. Rietveld refinements indicate that the occupancy factors of the carbon and oxygen sites of the carbonate group increase, while that of the chloride site decreases. In the CoAl-Cl CoAl-NO3 anion-exchange reaction, the XRPD patterns reveal the existence of two intermediate phases in addition to the initial CoAl-Cl and final CoAl-NO3 phases. The in situ data indicate that one of these intermediates is a mixed nitrate- and chloride-based LDH phase, where the disorder decreases as the nitrate content increases. The XRPD data of the partial CoAl-CO3 CoAl-SO4 anion-exchange reaction show that the process is a two-phase transformation involving a sulfate-containing LDH with a 1H polytype structure.

KW - Batteries and carbon-free energy storage

KW - Materials and energy storage

KW - Batterier og kulstoffri kemisk energilagring

KW - Materialer og energilagring

U2 - 10.1107/S0021889810011805

DO - 10.1107/S0021889810011805

JO - Journal of Applied Crystallography

JF - Journal of Applied Crystallography

SN - 0021-8898

IS - 3

VL - 43

SP - 434

EP - 447

ER -