Abstract: γ-AlOOH nanocrystaline with width of 10-30nm, length of 100-300nm and aspect ratio of 5-15 were prepared under hydrothermal condition by using aluminum chloride and sodium hydroxide as starting materials. Because of high proportion surface hydroxyl, the thermal decomposition of γ-AlOOH nanocrystalline demonstrates different features, and desorption of surface hydroxyl or chemisorbed water should be treated as separate stage. The thermal decomposition of γ-AlOOH nanocrystalline should be divided to four stages: 1) desorption of physisorbed water; 2) desorption of chemisorbed water; 3) desorption of molecular water and conversion into transition alumina; 4) desorption of residual hydroxyl in transition alumina. And the activation energies of the four stages are -1.21,-16.57,-167.62 and -7.61kJ/mol, respectively.

Key words: boehmite, thermal decomposition, kinetics, activation energy