Grafting of Alumina on SBA-15: Effect of Surface Roughness

• Published in: Langmuir Vol. 24; no. 17; pp. 9837 - 9842
• Main Authors: Zukal, A, S̅iklová, H, C̅ejka, J
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 02.09.2008
• Subjects: Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Materials: Nano-and Mesostructured Materials, Polymers, Gels, Liquid Crystals, Composites; Porous materials; Surface physical chemistry; Scanning electron microscopy; Binary compound; Roughness; Aluminium; NMR spectrometry; Nitrogen; Algorithm; X ray diffraction; Grafting; Porous material; Silica; Mesoporosity; Powder; Magic angle; Adsorption; Aqueous solution; Structure; Alumina; Smooth surface
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la801547u

Alumina-grafted materials were prepared by postsynthesis alumination of mesoporous SBA-15 silica in an aqueous solution of aluminum chlorhydrol. Prepared samples were characterized by nitrogen adsorption, scanning electron microscopy, X-ray powder diffraction, and 27Al magic-angle-spinning NMR. The successive grafting of alumina on SBA-15 leads to a gradual filling of the corona surrounding the mesopores. As a consequence smoothing of the mesopore surface takes place. The in-depth analysis of nitrogen adsorption data proves that the αs method affords real values of the structure parameters, while the Kruk, Jaroniec, and Sayari (KJS) procedure based on the BJH algorithm provides only effective data corresponding to cylindrical mesopores of smooth geometrical surface. The quantification of the roughness of the SBA-15 mesopore surface based on the comparison of data obtained from the αs plot and KJS method was carried out.