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Determining the aluminium occupancy on the active T-sites in zeolites using X-ray standing waves

Nature Materials volume 7, pages 551555 (2008) | Download Citation

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Abstract

Zeolites are microporous crystalline materials that find wide application in industry, for example, as catalysts and gas separators, and in our daily life, for example, as adsorbents or as ion exchangers in laundry detergents1. The tetrahedrally coordinated silicon and aluminium atoms in the zeolite unit cell occupy the so-called crystallographic T-sites. Besides their pore size, the occupation of specific T-sites by the aluminium atoms determines the performance of the zeolites2. Despite its importance, the distribution of aluminium over the crystallographic T-sites remains one of the most challenging, unresolved issues in zeolite science. Here, we report how to determine unambiguously and directly the distribution of aluminium in zeolites by means of the X-ray standing wave technique3 using brilliant, focused X-rays from a third-generation synchrotron source. We report in detail the analysis of the aluminium distribution in scolecite, which demonstrates how the aluminium occupancy in zeolites can systematically be determined.

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Acknowledgements

We thank the staff of the ESRF and the ID32 beamline, in particular L. Andre and H. Isern, for skillful technical assistance. Financial support by a grant (05 KS4GU3/4) to S.T. from the German Federal Ministry for Education and Research (BMBF) is gratefully acknowledged. Financial support from the Swiss National Science Foundation (PP002–110473) to J.A.v.B. is also gratefully acknowledged. We thank L. McCusker for careful reading of the manuscript.

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Affiliations

  1. ETH Zurich, Institute for Chemical and Bioengineering, HCI E127, 8093 Zurich, Switzerland

    • Jeroen A. van Bokhoven
  2. European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex 9, France

    • Tien-Lin Lee
    • , Sebastian Thieß
    •  & Jörg Zegenhagen
  3. Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK

    • Michael Drakopoulos
  4. Centre of Excellence NIS- Dipartimento di Chimica I.F.M., Università di Torino, Via P. Giuria 7, I-10125 Torino, Italy

    • Carlo Lamberti
  5. University Hamburg, Institut für Experimentalphysik, Luruper Chaussee 149, D-22761 Hamburg, Germany

    • Sebastian Thieß

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Correspondence to Jeroen A. van Bokhoven or Tien-Lin Lee.

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https://doi.org/10.1038/nmat2220

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