Synthesis of flower-like Boehmite (AlOOH) via a simple solvothermal process without surfactant

Boehmite (AlOOH) with hierarchical flower-like structures was synthesized by the solvothermal reaction of AlCl₃·6H₂O in the presence of ethanol and toluene at 200 °C for 24 h. The product was characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that boehmite with flower-like nanostructures, which aggregated together by the weak hydrogen bonds, was formed through dissolution-deposition process of boehmite microcrystals and the toluene has a great effect on the morphology of product in the reaction system. Meanwhile, the γ-Al₂O₃ was also obtained by calcination of above product at 500 °C for 2 h, and the flower-like morphology kept no change. The surface area of γ-Al₂O₃ powder was determined to be 166.8 m²/g by N₂ adsorption measurement. The possible formation mechanism of flower-like boehmite nanostructures was proposed and discussed.