The role of Fe nanospheres in energy releasing of DAP-4

Molecular perovskite energetic material DAP-4 is seen as a potential high-energy oxidant due to its high energy, high density, high oxidation capacity, and facile preparation technology. However, optimizing its energy release and reducing its thermal decomposition temperature are huge challenges for its future application. In this work, the role of iron (Fe) nanospheres in the energy release of DAP-4 was studied. Our research has shown that Fe powder can not only serve as a fuel to promote combustion, but also as an important catalyst to significantly improve the thermal decomposition, energy release, and burning rate of DAP-4. By adding 25% Fe nanospheres, the decomposition temperature of DAP-4 was reduced to 299.7 °C, which is the most reduction by 84.7 °C from 384.4 °C (raw DAP-4) to 299.7 °C (DAP-4/Fe-5 with 25wt% Fe nanospheres) was obtained. The decomposition activation energy also decreases by at least 69.5 kJ mol−1 from 229.4 kJ mol−1 (DAP-4) to 159.9 kJ mol−1 (DAP-4/Fe-1 with 5wt% Fe nanospheres). The combustion performance of DAP-4/Fe composites is significantly improved by a 4∼5 times shorter burn rate. The energy-releasing mechanism of DAP-4 with the presence of Fe nanospheres was proposed. FexOy at the surface of Fe nanospheres played an important role in the energy releasing of DAP-4. This work showed a new idea for the potential application of molecular perovskite energetic materials.