Room-temperature synthesis of hydrothermally stable aluminum-rich periodic mesoporous organosilicas with wormlike pore channels

Abstract

Hydrothermally stable Al-containing periodic mesoporous organosilicas with various Si/Al ratios as low as 5.6 were easily prepared at room temperature by NH4OH-catalyzed, CTAB-templated hydrolysis and condensation of 1,2-bis(triethoxysilyl)ethane and aluminum isopropoxide. Characterization data with XRD, TEM, SEM, nitrogen adsorption, 29Si and 27Al MAS NMR, pyridine-TPD, and hydrothermal test showed that the mesoporous materials possess wormlike channels with high textural porosity, tetrahedrally and octahedrally coordinated Al atoms in their textural structures, and weak acid sites whose contents are proportional to the amount of Al incorporated. It was also observed that the morphology of PMO samples changed with the incorporation of aluminum into the framework. Both Al-PMO with medium aluminum amount (Si/Al = 29) and Al-PMO with high aluminum amount (Si/Al = 5.6) were stable in boiling water for as long as 12 days owing to the presence of hydrophobic ethane bridging groups as well as the absence of sodium ions in the frameworks. © 2005 Elsevier Inc. All rights reserved.