Synthesis of γ-Al₂O₃ nanowires through a boehmite precursor route

Abstract

Crystalline γ-Al₂O₃ nanowires with diameter, 20–40 nm, length above 600 nm and aspect ratio above 30 have been successfully synthesized by thermal decomposition of boehmite (γ-AlOOH) precursors obtained via hydrothermal route by using AlCl₃, NaOH and NH₃ as starting materials. Thermogravimetric analysis (TG), differential thermal analysis (DTA), X-ray diffraction (XRD), transmission electron microscope (TEM), selected area electron diffraction (SAED) and high resolution transmission electron microscope (HRTEM) were used to characterize the features of the as-made γ-Al₂O₃ nanowires and their γ-AlOOH precursors. The pH value of the solution and the mixed precipitant play important roles in the formation of γ-AlOOH nanowires. After calcination at 500°C for 2 h, the orthorhombic γ-AlOOH transforms to cubic γ-Al₂O₃ and retains nanowire morphology.