Synthesis of γ-Al2O3 nanowires through a boehmite precursor route

Crystalline gamma-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 (gamma-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 gamma-Al2O3 nanowires and their gamma-AlOOH precursors. The pH value of the solution and the mixed precipitant play important roles in the formation of gamma-AlOOH nanowires. After calcination at 500A degrees C for 2 h, the orthorhombic gamma-AlOOH transforms to cubic gamma-Al2O3 and retains nanowire morphology.