Facile synthesis of highly thermally stable nanoporous γ-aluminas from aluminum alkoxide precursors

Abstract

The effects of aluminum alkoxide single source precursors on the sol–gel synthesis of highly thermally stable nanostructured alumina by nonionic triblock copolymer P123 were investigated. Different crystalline nanoporous alumina materials with large single or bimodal accessible pores were synthesized via an efficient single-step process starting from alkoxide precursors utilizing the evaporation-induced self-assembly (EISA) method. The effect of different types of organic groups within the molecular aluminum precursor were explored by variation from iso-propoxide (OⁱPr), as an alkoxy group, over phenoxide (OPh), as an aryloxy group, to the presence of ether functions within the alkoxy chains, represented by methoxyethoxide (OCH₂CH₂OCH₃) and methoxyethoxyethoxide (OCH₂CH₂OCH₂CH₂OCH₃) groups. The prepared samples were characterized by small and wide angle X-ray diffraction, N₂ adsorption–desorption, TGA-DTA, and TEM measurements. For the prepared aluminas porosity, surface area, and excellent thermal stability, as well as an adjustable pore size distribution were found which make them suitable for potential application in different processes where single or bimodal accessible pores are necessary.