Comparative textural study of highly ordered silicate and aluminosilicate mesoporous mesophase materials having different pore sizes

• Published in: Microporous and mesoporous materials 2001-06, Vol.44-45, p.33-40
• Main Authors: Fenelonov, V.B., Derevyankin, A.Yu, Kirik, S.D., Solovyov, L.A., Shmakov, A.N., Bonardet, J.-L., Gedeon, A., Romannikov, V.N.
• Format: Article
• Language: English
• Subjects: Honeycomb structure model; MCM-41; SBA-15; Surface roughness
• ISSN: 1387-1811; 1873-3093
• DOI: 10.1016/S1387-1811(01)00166-4

Honeycomb structure model was applied for describing surface properties in the MCM-41 and SBA-15 types of highly ordered silicas and aluminosilicates with different nominal mesopore diameters: about 4 nm and about 10 nm. As shown, calculations of internal specific surface area Ame require a heterogeneity of this surface to be taken into account, the latter being quantified by the roughness coefficient β. These calculations at the condition β=1.0 will allow to estimate the lower limit of specific surface area of the materials only, which will correspond to the perfectly smooth walls of mesopores. This description seems to be valid for the MCM-41 type systems, for which β is about 1.1–1.2. On the contrary, β is found to exceed 1.5 for the SBA-15 type materials. This fact is probably due to an essential non-smoothness of the mesopore surface in these systems and may be associated with their synthesis conditions.