The steric influence of extra-framework cations on framework flexibility: An LTA case study

Mero Lee U. Cornelius; Lisa Price; Stephen A. Wells; Leslie F. Petrik; Asel Sartbaeva

doi:10.1515/zkri-2019-0016

The steric influence of extra-framework cations on framework flexibility: An LTA case study

Mero Lee U. Cornelius, Lisa Price, Stephen A. Wells, Leslie F. Petrik, Asel Sartbaeva

University of the Western Cape

Research output: Contribution to journal › Article › peer-review

12 Citations (SciVal)

108 Downloads (Pure)

Abstract

The theoretical extent of framework flexibility of Zeolite A (LTA) in response to the steric and geometric effects of different Si/Al compositions and extra-framework cation content has been explored using GASP software. Flexibility windows and compression mechanisms for siliceous LTA and aluminosilicate Na-LTA, Ca-LTA and K-LTA have been modelled. As expected, relatively small cations in the zeolite pores have little effect on the range of flexibility observed. Aluminosilicate LTA, Na-LTA and Ca-LTA frameworks exhibit identical flexibility windows and these frameworks also follow the same compression mechanisms. The introduction of larger K⁺ ions, however, results in greater steric hindrance. This restricts the flexibility of the framework and alters the compression mechanism to accommodate these larger cations. It is shown that the limits of the flexibility window of Zeolite A are dependent on framework aluminium content and extra-framework cation size.

Original language	English
Pages (from-to)	461-468
Number of pages	8
Journal	Zeitschrift fur Kristallographie - Crystalline Materials
Volume	234
Issue number	7-8
Early online date	16 Jul 2019
DOIs	https://doi.org/10.1515/zkri-2019-0016
Publication status	Published - 26 Jul 2019

Funding

Acknowledgements: The authors would like to thank the National Research Foundation (NRF) of South Africa for funding the research project and the Commonwealth Scholarship Commission in the United Kingdom for funding the research visit to the University of Bath, United Kingdom. Asel Sartbaeva would further like to thank the Royal Society for funding. Furthermore, the authors would like to express their appreciation for the academic support of the Environmental and Nano Sciences (ENS) research group at the University of the Western Cape (South Africa) and the Sartbaeva research group at the University of Bath (United Kingdom) during the research. SAW acknowledges funding from the ERC under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 648283 “GROWMOF”).

Keywords

cation
compression
extra-framework
flexibility
flexibility window
framework
GASP
geometric simulation
steric interaction
structure-breaking
structure-directing
template
template based geometric simulation
zeolite

ASJC Scopus subject areas

General Materials Science
Condensed Matter Physics
Inorganic Chemistry

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10.1515/zkri-2019-0016

Cornelius_revised_accepted.PDF
The final publication is available at www.degruyter.com
Accepted author manuscript, 920 KB

Cite this

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title = "The steric influence of extra-framework cations on framework flexibility: An LTA case study",

abstract = "The theoretical extent of framework flexibility of Zeolite A (LTA) in response to the steric and geometric effects of different Si/Al compositions and extra-framework cation content has been explored using GASP software. Flexibility windows and compression mechanisms for siliceous LTA and aluminosilicate Na-LTA, Ca-LTA and K-LTA have been modelled. As expected, relatively small cations in the zeolite pores have little effect on the range of flexibility observed. Aluminosilicate LTA, Na-LTA and Ca-LTA frameworks exhibit identical flexibility windows and these frameworks also follow the same compression mechanisms. The introduction of larger K+ ions, however, results in greater steric hindrance. This restricts the flexibility of the framework and alters the compression mechanism to accommodate these larger cations. It is shown that the limits of the flexibility window of Zeolite A are dependent on framework aluminium content and extra-framework cation size.",

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author = "Cornelius, {Mero Lee U.} and Lisa Price and Wells, {Stephen A.} and Petrik, {Leslie F.} and Asel Sartbaeva",

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AU - Petrik, Leslie F.

AU - Sartbaeva, Asel

PY - 2019/7/26

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The steric influence of extra-framework cations on framework flexibility: An LTA case study

Abstract

Funding

Keywords

ASJC Scopus subject areas

Access to Document

Other files and links

Fingerprint

Enhancement Grant from the Royal Society entitled "Pores for thought: rational design and synthesis of zeolites"

Transfer from Oxford to Bath of RS Fellowship

Cite this

The steric influence of extra-framework cations on framework flexibility: An LTA case study

Abstract

Funding

Keywords

ASJC Scopus subject areas

Access to Document

Other files and links

Fingerprint

Projects

Enhancement Grant from the Royal Society entitled "Pores for thought: rational design and synthesis of zeolites"

Transfer from Oxford to Bath of RS Fellowship

Cite this