Controlling the channel diameter of the mesoporous molecular sieve MCM-41

C Cheng, Wuzong Zhou, DH Park, J Klinowski, M Hargreaves, LF Gladden

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123 Citations (Scopus)

Abstract

We describe a simple method of controlling the channel diameter of the mesoporous molecular sieve MCM-41 in the 26.1-36.5 Angstrom range and the wall thickness in the 13.4-26.8 Angstrom range while using the same gel mixture. This is achieved by varying the synthesis temperature in the 70-200 degrees C range and/or reaction times in the 0.5-96 h range. The unit cell parameter, channel diameter, thickness of the channel wall, surface area, degree of polymerization and grain morphology were monitored by X-ray diffraction, N-2 adsorption, Si-29 magic-angle-spinning NMR and transmission electron microscopy. MCM-41 with wider and thicker-walled channels and higher degree of polymerization is prepared at higher temperatures and at longer reaction times. Thick-wall MCM-41 has higher thermal stability but lower surface area. The material with the thickest channel wall ever reported (26.8 Angstrom) can withstand calcination at nearly 1000 degrees C with little structural damage. We suggest a mechanism for the increase of wall thickness and channel diameter. Fascinating morphological features involving sealed silicate 'tubes' and 'vesicles' up to 1200 Angstrom in diameter are observed.

Original languageEnglish
Pages (from-to)359-363
Number of pages5
JournalJournal of the Chemical Society, Faraday Transactions
Volume93
Issue number2
DOIs
Publication statusPublished - 21 Jan 1997

Keywords

  • MECHANISM

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