Synthesis of nanostructured γ-alumina with a cationic surfactant and controlled amounts of water

Nanostructured crystalline γ-alumina was synthesized by a simpler and improved method proposed here from aluminum alkoxide precursor in the presence of a cationic surfactant and controlled amounts of water under hydrothermal conditions without any extra additives such as hydrolysis controlling agents. The material synthesized with a stoichiometric amount of water (H2O/Al = 2) was a mesoporous molecular sieve with a 'wormhole-like' pore structure. With increasing amounts of water (H2O/Al = 10 or 20), bundles of γ-alumina nanofibers were formed, and with H2O/Al > 20, materials with no definite morphology were formed, probably due to too fast hydrolysis of the precursor. The nanostructured materials had high surface areas and a good thermal stability.