The Synthesis and Application of the Mesoporous Molecular Sieves MCM‐41 — A Review

Abstract

We report a “delayed neutralization” process for the preparation of highly‐ordered aluminosilicate MCM‐41 molecular sieves with high thermal and hydrothermal stability, and sharp pore size distribution. However, the structural order and pore size are dependent on the carbon chain length. In the mixture surfactant systems, the pore size of the MCM‐41 materials could be fine‐tuned. The pore size can be extended from 2.5 to 4.5 nm by adding a suitable amount of hydrocarbons. The tubular morphology of the MCM‐41 material of 0.3 to 10 micrometers diameter, where the wall consists of coaxial cylindrical pores of nanometers MCM‐41, can be obtained by careful control of the surfactant‐water content and the rate of condensation of silica. An optimum condition for automatic synthesis of the hierarchical TWT structure has been accomplished. The addition of 1‐alkanols as cosurfactant would not only improve the order of the MCM‐41 hexagonal structure but also promote the formation of micrometer‐sized hierarchical materials, for example: tubules‐within‐tubule and uniform‐sized hollow spheres of diameter 5.0 ± 1.0 μm. However, the inside of the micron spheres has intricate structures possessing various topological genus ranks. The MCM‐41 is a good supporter for Molybdenum oxide catalysts. The rate of deactivation in the catalytic reaction of ethyl‐benzene dehydrogenation to styrene increases in the order: MT < MP < SiO2. The physically mixed samples have higher catalytic activity than impregnated ones.

Highly ordered pure and indium-incorporated MCM-41 mesoporous adsorbents: synthesis, characterization and evaluation for dye removal

“…The average pore diameter was estimated from the TEM image assuming that the average thickness of the pore wall (W t ) is 0.68 nm (Table 1). This value was found to be 3.78 ± 0.06 nm and falls within the acceptable range for calcined MCM-41 [43,52,53]. The TEM image of IM0.1 sample shown in (Fig.…”

Recent Advances in Processing and Characterization of Periodic Mesoporous MCM-41 Silicate Molecular Sieves

“…A number of reviews 1,11,[38][39][40][41][42][43][44]47,48,[50][51][52][53][54][55][96][97][98][99][100][101][102] have appeared on various aspects of different mesoporous materials. However, it is quite remarkable that only one report 43 has appeared, as early as 1996, exclusively on MCM-41, considering its synthesis, characterization, formation mechanism, physicochemical properties, and applications.…”

Structural and Morphological Control of Cationic Surfactant-Templated Mesoporous Silica

“…The lower pH leads to further silica condensation and thus a thicker wall (ca. 1.7 nm). , In fact, the pH is low enough that as-synthesized materials can be directly calcined without the collapse of the mesostructure . For similar reasons, repeated pH adjustments often lead to a more stable MCM-41 material …”