Abstract
A synthetic route was developed for a novel hexagonal mesoporous silica that has remarkably wide channel diameters and thick walls. The procedure involved the acid-catalyzed hydrolysis of tetraethylorthosilicate in a water/ethanol/isopropoanol solvent mixture while employing 1-hexadecylamine as a templating agent and mesitylene as an auxiliary agent. After removal of the template by either extraction with ethanolic hydrochloric acid or by calcination at 550
°C, the resulting mesoporous materials had surface areas of 1283 and 1211
m
2/g. The channel diameters were found to be 47.2–51.1
Å, while the wall thicknesses were 20.9–21.1
Å. X-ray powder diffraction demonstrated that the novel mesoporous silica belonged to the MCM-41 structural family. Notably, they displayed higher thermal and hydrothermal stabilities, and have higher surface areas than conventionally prepared MCM-41 silica. The thickest channel walls (21.1
Å) can withstand calcination to nearly 850
°C with minimal structural damage. The calcined sample was more resistant to hydrothermal treatment in boiling water than was the solvent-extracted product but both materials showed minimal change after 25
h of hydrothermal treatment.