Exploring the Roles of ZIF-67 as an Energetic Additive in the Thermal Decomposition of Ammonium Perchlorate

Energetic additives can effectively increase the heat release of ammonium perchlorate (AP) decomposition to prevent nonenergetic additives from decreasing the energy density of composite solid propellants. However, the roles of energetic additives are unclear due to their complex changes in the decomposition process. Using ZIF-67 as a model energetic additive, we investigate its roles and catalytic processes in the decomposition of AP, especially the effect on heat release. We find that the decomposition process includes two periods: low-temperature oxidation of ZIF-67 by AP and high-temperature catalytic decomposition of excess AP. The oxidation of ZIF-67 can release a mass of heat and provide oxidation products for catalytic decomposition of excess AP. Meanwhile, the heat release of excess AP is increased to 2.33 times compared with pure AP (1.83 vs 0.78 kJ·g–1), and the relationship between heat release and the content of ZIF-67 is quantified. Our results provide new insights into the roles of MOFs in enhancing the thermal decomposition of AP.