Hydrothermal synthesis of microscale boehmite and gamma nanoleaves alumina

Novel uniform single-crystal boehmite leaf-like nanosheets with high anisotropy (with a lateral size of (4.5 +/- 0.5 mu m) x (9.0 +/- 1.0 mu m) and a thickness of 60-90 nm) and flower-like superstructures consisting of single-crystal petals were synthesized for the first time by a simple hydrothermal method. After calcination, those boehmite structures can be transformed into single-crystal gamma-alumina nanostructures while keeping their morphology. The morphologies and the crystal structures of single-crystal boehmite nanoleaves and flower-like superstructures were characterized by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and high resolution transmission electron microscopy (HRTEM). The formation mechanism of the nanoleaves and flower-like superstructure is also discussed. The synthesis of uniform single-crystal boehmite and gamma-alumina is highly helpful to study various properties of these anisotropic structures. (C) 2007 Elsevier B.V. All rights reserved.