Sorbate Rearrangement and Cation Migration in HFC-134 Loaded NaY Zeolite: a Temperature Dependent Synchrotron Powder Diffraction Study

Abstract:

The HFC-134/NaY binding has been monitored by temperature dependent X-ray powder diffraction. Diffraction patterns were obtained as a function of different loading levels to investigate the rearrangement of the cations and of the HFC-134 molecules, in the temperature range 100-230 K. In situ real-time data were collected using a Translating Imaging Plate System (TIPS) at the NSLS (USA). Rietveld structure refinements were performed for the HFC-134 (32 molecules per unit cell [m/uc = molecules per unit cell] or 4 molecules per supercage [m/sc = molecules per supercage]) using data collected from 100 to 230 K. A phase transition is observed at about 180 K (A to B phase transition) where a disordering of the HFC-134 molecule takes place and modification of its surrounding due to Na⁺ migrations is observed. These results are preliminary and the experiment with the 32 m/uc should be repeated in order to assess whether the observed effect is reproducible.

• Periodical: Materials Science Forum (Volumes 443-444)
• Pages: 295-298
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.443-444.295
• Online since: January 2004
• Authors: A.F. Gualtieri, P. Norby, C. P. Grey, J.C. Hanson
• Keywords: HFC-134/NaY, In Situ Studies, Rietveld Refinement, Synchrotron Powder Diffraction

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