Sách Influence of the Silica-to-Surfactant Ratio and the pH of Synthesis on the Characteristics of Mesopo

The presence of ordered nanoporous materials has been known for more than a century.1 Since the discovery of M41S mesoporous materials in 1992, there has been an increasing interest in the design of novel porous materials tailored with various pore organisations and dimensions for potential applications in separation, catalysis, chemical sensing and optical coating.2,3 The use of mesoporous materials of MCM-41 as carriers for basic guest species has been proposed by Weitkamp et al.4 This material is usually synthesised in a basic medium and in the presence of surfactant cations.5 However, MCM-41 material is limited to a pore size of about 80 Å, and, because of this, it is not suitable for processing large biomolecules such as protein and enzymes.6 Even though this material has a quite high thermal stability, it loses its structure when exposed to high-temperature steam or boiling water. The collapse of the structure limits the applications of MCM-41, especially in catalytic reactions involving aqueous solutions