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Indexed by:期刊论文

Date of Publication:2011-06-21

Journal:PHYSICAL CHEMISTRY CHEMICAL PHYSICS

Included Journals:SCIE、PubMed、Scopus

Volume:13

Issue:23

Page Number:11248-11253

ISSN No.:1463-9076

Abstract:The effect of zeolite Y precursor on the formation of MCM-41 containing zeolite Y building units has been investigated by means of UV Raman spectroscopy, X-ray diffraction (XRD), infrared spectroscopy (IR) and electron microscopy (SEM and TEM). Study of the precursor formation shows that 4-membered ring species are formed at the early stages of crystallization. Zeolite Y begins to appear after crystallization for 4 h, and its crystallinity increases with increasing crystallization time. However, lowering the pH value to similar to 9.3 in the second step not only facilitates the polymerization of silicate species, but also leads to the structural change of the precursors. Pure MCM-41 mesoporous phase containing zeolite Y building units and the mixture of zeolite Y and MCM-41 can be formed combining the effects of the precursor structure and the pH adjustment.