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Changes in the medium-range order during crystallization of aluminosilicate zeolites characterized by high-energy X-ray diffraction technique

Wakihara, T; Suzuki, Y; Fan, W; Saito, S; Kohara, S; Sankar, G; ... Okubo, T; + view all (2009) Changes in the medium-range order during crystallization of aluminosilicate zeolites characterized by high-energy X-ray diffraction technique. J CERAM SOC JPN , 117 (1363) 277 - 282.

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Abstract

ZSM-5 and faujasite, which are aluminosilicate zeolites with different compositions, were synthesized without using organic structure-directing agents, and the changes in the medium-range order during the crystallization of ZSM-5 and faujasite were characterized by high-energy X-ray diffraction (HEXRD) technique. It is found that that the amorphous aluminosilicates have larger fraction of 4 membered ring (4R), compared to 6 membered ring (6R) that is the most dominant in amorphous silica. Furthermore, HEXRD measurements reveal that changes in the medium-range order are characteristic for each zeolite although crystallizations of both zeolites proceeded via a similar way: that is, the dissolution of amorphous precursors to solution followed by the nucleation and crystal growth of zeolite from the soluble species. In ZSM-5 crystallization, no major changes in the medium-range order are observed although slight decrease of the fraction of 411 is confirmed. On the other hand, clear changes in the medium-range order, especially on the ordering of 4R and 611 are confirmed in faujasite crystallization. (C)2009 The Ceramic Society of Japan. All rights reserved.

Type:Article
Title:Changes in the medium-range order during crystallization of aluminosilicate zeolites characterized by high-energy X-ray diffraction technique
Keywords:Zeolite, X-ray, diffraction, Crystallization, Crystal growth, ATOMIC-FORCE MICROSCOPY, HYDROTHERMAL SYNTHESIS, DISORDERED MATERIALS, NEUTRON-DIFFRACTION, CRYSTAL-GROWTH, PRECURSORS, ELUCIDATION, MECHANISM, GLASSES, SILICA
UCL classification:UCL > School of BEAMS > Faculty of Maths and Physical Sciences > Chemistry

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