Synthesis of nanostructured γ-AlOOH and its accelerating behavior on the thermal decomposition of AP

Abstract

The hydrothermal treatment of γ-AlOOH agglomerates was introduced to synthesize nanostructured γ-AlOOH. Various characterizations were carried out to understand the synthesis procedure and the relationship between the shape of γ-AlOOH and its accelerating behavior for the thermal decomposition of ammonium perchlorate (AP). XRD, SEM and HRTEM showed that the γ-AlOOH nanoplates, nanorods and nanocubes with exposed (031), (110) and (001) facets, respectively, could be synthesized under controllable conditions. The DSC results showed that the addition of γ-AlOOH nanoplates, nanorods and nanocubes to AP remarkably decreased the decomposition temperature of AP from approximately 450 °C to 334 °C, 345 °C, and 357 °C, respectively. As the preferred additive, the γ-AlOOH nanoplate addition resulted in a decrease in the activation energy of AP from 346.29 kJ mol⁻¹ to 144.73 kJ mol⁻¹, determined by nonisothermal kinetic analysis. XRD, FT-IR and XPS results revealed that the γ-AlOOH phase transformed to γ-Al₂O₃ and α-AlOOH after being used as an additive for the AP decomposition; the excessive surface hydroxyls obtained by the exposed (031) facet of γ-AlOOH nanoplates, proved to be beneficial for accelerating AP decomposition.