Issue 47, 2008

Amorphization of faujasite at high pressure: an X-ray diffraction and Raman spectroscopy study

Abstract

In situ X-ray diffraction and Raman spectroscopy measurements of synthetic powdered samples of faujasite 13X were carried out at high pressure using diamond anvil cells. Structural changes are detected, linked to a progressive reduction in crystallinity, before complete amorphization of the material. Three distinct compressibility regions are clearly observed, delimited by two discontinuities in the pressure dependence of the faujasite volume around 2 and 3.5 GPa. The transition from the crystal to the amorphous state is incomplete and partially reversible below pressures of between 8 and 12 GPa, depending on the pressure-transmitting medium used. This partial recovery of the initial structure, at least on a local level, could be related to the presence of hydrated sodium ions in the faujasite framework. In addition, the position of the first sharp diffraction peak in the X-ray diffraction pattern of a fully amorphous sample recovered from 24 GPa is consistent with the presence of 4-membered rings of tetrahedra and the persistence of a significant number of larger rings as compared to a dried amorphous faujasite precursor.

Graphical abstract: Amorphization of faujasite at high pressure: an X-ray diffraction and Raman spectroscopy study

Article information

Article type
Paper
Submitted
09 Jun 2008
Accepted
25 Sep 2008
First published
24 Oct 2008

J. Mater. Chem., 2008,18, 5746-5752

Amorphization of faujasite at high pressure: an X-ray diffraction and Raman spectroscopy study

A. Isambert, E. Angot, P. Hébert, J. Haines, C. Levelut, R. Le Parc, Y. Ohishi, S. Kohara and D. A. Keen, J. Mater. Chem., 2008, 18, 5746 DOI: 10.1039/B809774G

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