Synthesis of ordered mesoporous aluminosilicate under a low surfactant/silica molar ratio condition

Ordered mesoporous aluminosilicate materials with atomic Si/Al ratios of 16-64 were synthesized at a very low molar ratio of surfactant/silica (0.12) by using aluminium chloride hexahydrate and TEOS as the sources of aluminium and silicon. The resulting materials were characterized by XRD, TEM, FTIR and nitrogen sorption. As the NaOH/Si molar ratio increases from 0.2 to 0.6, the products obtained change from hexagonal MCM-41 to cubic MCM-48. The quality of the product rapidly deteriorates as the aluminium content of the solid increases beyond a certain limit. XRD shows that the substitution of the silicon by the large aluminium atoms leads to the expansion of the unit cell.