화학공학소재연구정보센터
Catalysis Today, Vol.68, No.1-3, 11-20, 2001
Comparison of disordered mesoporous alumino silicates with highly ordered Al-MCM-41 on stability, acidity and catalytic activity
A simple procedure has been described to directly synthesize hydrothermally stable, disordered mesoporous aluminosilicate materials with strong surface acidity by using a polymer aluminosilicate precursor, and cationic surfactant cetyltrimethylammonium bromide (CTAB) as the structure-directing agent. The comparison of stability, acidity and catalytic activity for the disordered mesoporous materials and Al-MCM-41 has been studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), N-2 adsorption/desorption, infrared spectra, NH3-temperature program desorption (NH3-TPD) and Al-27 MAS NMR techniques. The results show that the disordered mesoporous materials are very similar to mesoporous material MCM-41 as regards its uniform mesopore sizes at the mean value of 3.0 nm, while the mesoporous channel arrangement is fully disordered similar to that for KIT-1 prepared by the additive of organic salts. Scanning electron microscopic (SEM) images show that the products have regular microscopic arrays and layer sheet-like morphology. The disordered mesoporous materials are hydrothermally more stable than highly ordered MCM-41. Furthermore, they show stronger acid strength and higher cracking activities than Al-containing MCM-41.