Morphologically controlled synthesis of mesoporous alumina

The morphologically controlled synthesis of mesoporous alumina using Al(NO3)(3)/NH3/urea/surfactant reaction system is demonstrated. Both the mesostructures and morphologies of the resulting alumina can be effectively controlled via adjusting the synthesis parameters, including reactant compositions, surfactant kinds and hydrothermal conditions. With the aid of surfactants, mesoporous alumina with spheres, rods, fibers and three-dimensional dumbbell, flower-like hierarchical superstructures on the microscopic scale has been obtained. Through characterization by N-2 physisorption, X-ray diffraction, electron microscopy and thermogravimetry analysis, the effects of synthesis conditions on structures and shapes of products are explained and the possible formation mechanism of the controlled morphologies is also proposed. (c) 2006 Elsevier Inc. All rights reserved.