Synthesis and characterization of hierarchically structured aluminosilicates

Sikander H. Hakim, Iowa State University
Brent H. Shanks, Iowa State University

This article is from Journal of Materials Chemistry 21 (2011): 7364, doi: 10.1039/c1jm10176e. Posted with permission.

Abstract

Catalytically active aluminosilicate materials with hierarchical porous structures are produced. A spontaneous self-assembly in aqueous solution starting from component alkoxides resulted in patterned powders without the aid of any templating agent. SEM and N2 adsorption-desorption studies demonstrated regular array of macrochannels connected with micro-mesoporous walls. FTIR of adsorbed pyridine revealed the presence of both Brønsted and Lewis acid sites. Although the synthesis procedure is markedly distinct from sol-gel phenomena, the structure and acidity in the final materials could be manipulated in terms of sol-gel parameters such as composition, pH, temperature, and addition order. Not one parameter set could be identified to provide both best structure and maximum acidity; a compromise between the two was essential. The synthesized aluminosilicate catalysts were active in the esterification reaction of palmitic acid.