Investigation Of Structural Stability Of Microporous Materials Under High Temperature And High Pressure

In this thesis, high pressure research is focused on investigation of structural stability of microporous materials under high temperature and high pressure, including the phase transition behavior ofα-ZrP with layerd structure and synthetic zeolites with faujasite (FAU) structure, as well as the value of zeolites framework supporting external pressure.α-ZrP with well layerd structure is widely used in instrcturial processes as ion exchanger, sorbent and catalysts. The Structural stability of microporous zeolite is crucial to its application. The thermal stability ofα-ZrP has been extensively studied. However, little is known about the stability behavior ofα-ZrP at a certain pressure.In this thesis, we have carefully studied the structural stability ofα-ZrP under high temperature and high pressure. After decompression, the samples from high pressure apparatus were characterized by X- ray diffraction and IR. The results indicate that the layered structure ofα-Zr(HPO4)2·H2O was still retained whenthe pressure was up to 13.5GPa and temperature was about 25℃, except the crystallinity of the sample decreased lightly with increasing pressure. This layered material has very good rigidity and will be of important applications.In addition,Since Y zeolite was synthesized in 1964, the properties of it,s thermal stability , ion exchange, katalyze and sorption have been investigated widely, but there are only a few reports on the Structural Stability of Y Zeolite under high pressure. However, the structural stability of zeolites is very important to their instrcturial applications. So In this paper, the structural stability of Y zeolite under room temperature and high pressure has been also investigated carefully, and the samples which were taken from the pressure apparatus after decompression were characterized by X-ray diffraction and IR spectroscopy.The results show that the structure stability of Y zeolite decreases with the pressure increasing. The structure of Y zeolite partly collapsed when pressure was up to 9GPa at room temperature, which seems to be driven by the severe distortion of double six-membered rings joining the adjacent sodalite cages to form the zeolitic lattice.Effects of pressure on open-framework cage structure, that are stabilised in large part because of the surface free energy compared with that of fully-densified bulk materials. Investigationof structural stability of microporous materials under high temperature and high pressure, which can resolve some problems of microporous materials applied under high temperature and high pressure.