Morphology Controllable Synthesis of γ-Alumina Nanostructures via an Ionic Liquid-Assisted Hydrothermal Route

Abstract

The precursors for boehmite and γ-Al 2 O 3, aluminum acetate hydroxide [(CH 3 COO) 2 Al(OH)] with various morphologies including nanoleave, nanofibers, and hierarchically nanostructured microflowers, have been successfully synthesized by an ionic liquid-assisted hydrothermal synthetic method using 1-butyl-2, 3-dimethyl imidazollium chloride ([bdmim][Cl]) as a template. The effects of the ionic liquid [bdmim][Cl] on the morphology of the precursors aluminum acetate hydroxide have been investigated systematically. The boehmite and γ-Al 2 O 3 nanostructures were obtained by calcining the as-synthesized precursors at 300 and 600 °C for 2 h, respectively, preserving the same morphology. The proposed formation mechanism of the precursors has also been investigated. The obtained products were characterized by several techniques, such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and N 2 adsorption−desorption technique.