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The flexibility window in zeolites

Nature Materials volume 5, pages 962965 (2006) | Download Citation

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Abstract

Today synthetic zeolites are the most important catalysts in petrochemical refineries because of their high internal surface areas and molecular-sieving properties1,2. There have been considerable efforts to synthesize new zeolites with specific pore geometries3,4, to add to the 167 available at present. Millions of hypothetical structures have been generated on the basis of energy minimization5, and there is an ongoing search for criteria capable of predicting new zeolite structures. Here we show, by geometric simulation6,7,8, that all realizable zeolite framework structures show a flexibility window over a range of densities. We conjecture that this flexibility window is a necessary structural feature that enables zeolite synthesis, and therefore provides a valuable selection criterion when evaluating hypothetical zeolite framework structures as potential synthetic targets. We show that it is a general feature that experimental densities of silica zeolites lie at the low-density edge of this window—as the pores are driven to their maximum volume by Coulomb inflation. This is in contrast to most solids, which have the highest density consistent with the local chemical and geometrical constraints.

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Acknowledgements

This work was supported by NSF grants NIRT-0304391 and DMR-0425970. We acknowledge M. Foster for discussions.

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Affiliations

  1. Department of Physics and Astronomy, Arizona State University, Tempe, Arizona 85287-1504, USA

    • Asel Sartbaeva
    • , Stephen A. Wells
    • , M. M. J. Treacy
    •  & M. F. Thorpe

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Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to M. F. Thorpe.

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DOI

https://doi.org/10.1038/nmat1784

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