Directing the pore dimensions in the mesoporous molecular sieve MCM-41

We describe a straightforward method of controlling the channel diameter of the mesoporous molecular sieve MCM-41 in the 26.1–36.5 Å range and the wall thickness in the 13.4–26.8 Å range while using the same gel mixture. The thickest-walled material can withstand calcination at 900°C with little structural damage. We have observed new morphological features involving sealed silicate ‘tubes’ and ‘vesicles’ up to 1200 Å across, and suggest a mechanism for the increase of wall thickness and channel diameter.