High-temperature synthesis of ordered mesoporous silicas from solo hydrocarbon surfactants and understanding of their synthetic mechanisms

Ordered mesoporous silicas (SBA-15 or MCM-41) have been directly hydrothermally synthesized at high temperatures (160-180 'C) by using a solo hydrocarbon surfactant (P123 or CTAB). 'H NMR spectra and thermogravimetric (TG) curves showed that these hydrocarbon surfactants decomposed during the preparation process at such high temperatures. Accordingly, we proposed that the surfactant micelle plays an important role during the cooperative self-assembly of the silicates and surfactants in the initial stage for the formation of basic mesostructure, and it is no longer indispensable in the subsequent hydrothermal treatment at high temperature.