Thermal Decomposition Kinetics of γ-AlOOH Nanocrystalline Prepared by Hydrothermal Method

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.