High-Pressure Phase Transition, Pore Collapse, and Amorphization in the Siliceous 1D Zeolite, TON

Published on 2018-02-13T09:29:45Z (GMT) by
The siliceous zeolite TON with a 1-D pore system was studied at high pressure by X-ray diffraction, infrared spectroscopy, and DFT calculations. The behavior of this material was investigated using nonpenetrating pressure-transmitting media. Under these conditions, a phase transition from the <i>Cmc</i>2<sub>1</sub> to a <i>Pbn</i>2<sub>1</sub> structure occurs at close to 0.6 GPa with doubling of the primitive unit cell based on Rietveld refinements. The pores begin to collapse with a strong increase in their ellipticity. Upon decreasing the pressure below this value the initial structure was not recovered. DFT calculations indicate that the initial empty pore <i>Cmc</i>2<sub>1</sub> phase is dynamically unstable. Irreversible, progressive pressure-induced amorphization occurs upon further increases in pressure up to 21 GPa. These changes are confirmed in the mid- and far-infrared spectra by peak splitting at the <i>Cmc</i>2<sub>1</sub> to <i>Pbn</i>2<sub>1</sub> phase transition and strong peak broadening at high pressure due to amorphization.

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Thibaud, Jean-Marc; Rouquette, Jérôme; Hermet, Patrick; Dziubek, Kamil; Gorelli, Federico A.; Santoro, Mario; Garbarino, Gaston; Alabarse, Frederico G.; Cambon, Olivier; Renzo, Francesco Di; van der Lee, Arie; Haines, Julien (2018): High-Pressure Phase Transition, Pore Collapse, and

Amorphization in the Siliceous 1D Zeolite, TON. ACS Publications. Collection.