Pressure-induced oversaturation and phase transition in zeolitic imidazolate frameworks with remarkable mechanical stability
Casati, Nicola PM
Lampronti, Giulio I
Moggach, Stephen A
Royal Society of Chemistry
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Zhao, P., Bennett, T. D., Casati, N. P., Lampronti, G. I., Moggach, S. A., & Redfern, S. A. (2015). Pressure-induced oversaturation and phase transition in zeolitic imidazolate frameworks with remarkable mechanical stability. Dalton Transactions, 44 4498-4503. https://doi.org/10.1039/C4DT02680B
Zeolitic imidazolate frameworks (ZIFs) 7 and 9 are excellent candidates for CO2 adsorption and storage. Here, high-pressure X-ray diffraction is used to further understand their potential in realistic industrial applications. ZIF-7 and ZIF-9 are shown be able to withstand high hydrostatic pressures whilst retaining their porosity and structural integrity through a new ferroelastic phase transition. This stability is attributed to the presence of sterically large organic ligands. Results confirm the notable influence of guest occupancy on the response of ZIFs to pressure; oversaturation of ZIFs with solvent molecules greatly decreases their compressibility and increases their resistance to amorphisation. By comparing the behaviours of both ZIFs under high pressure, it is demonstrated that their mechanical stability is not affected by metal substitution. The evacuated ZIF-7 phase, ZIF-7-II, is shown to be able to recover to the ZIF-7 structure with excellent resistance to pressure. Examining the pressure-related structural behaviours of ZIF-7 and ZIF-9, we have assessed the great industrial potential of ZIFs.
This work was supported by the Cambridge Commonwealth, European and International Trust; China Scholarship Council; Trinity Hall, University of Cambridge; UK Science & Technology Facilities Council. We thank anonymous reviewers for their valuable suggestions on the improvement of this manuscript.
External DOI: https://doi.org/10.1039/C4DT02680B
This record's URL: https://www.repository.cam.ac.uk/handle/1810/247674
Attribution 2.0 UK: England & Wales
Licence URL: http://creativecommons.org/licenses/by/2.0/uk/