Energetic molecular perovskites have emerged as an important class of high-energy oxidizers owing to their high energy density, structural tunability, and excellent application potential in advanced propellants and explosives. Among them, ammonium perchlorate-based molecular perovskite DAP-4 exhibits outstanding energy characteristics. However, it has a relatively high thermal decomposition threshold, which limits its ignition and combustion efficiency. In a recent study published in Energetic Materials Frontiers , a team of researchers from China developed Fe-doped carbon composite catalysts that effectively regulate the thermal decomposition and combustion behavior of DAP-4 through the synergistic catalytic effects of iron oxide nanoparticles and carbonaceous substrates.
"Fe-doped carbon composites exhibit intrinsic catalytic activity toward the thermal decomposition and combustion of DAP-4,” says corresponding author Shao-li Chen. "Highly dispersed FeOx nanoparticles promote hydrogen transfer between fuel cations and perchlorate anions, thereby accelerating decomposition and enhancing combustion reactions."
The researchers prepared a series of Fe-Carbon composite catalysts containing different loadings of iron oxide nanoparticles through a high-temperature carbonization strategy. Their catalytic performance was evaluated using thermal analysis, kinetic calculations, evolved-gas characterization, and combustion experiments.
“We found that introducing only 5 wt% Fe-Carbon catalyst markedly improves the thermal decomposition behavior of DAP-4,” shares Chen. “The optimized Fe-Carbon-3 catalyst lowers the decomposition peak temperature by approximately 25 °C , while Fe-Carbon-2 achieves the greatest reduction in apparent activation energy, decreasing it by 16.25 kJ mol ⁻ ¹ .
Mass spectrometry further confirmed accelerated evolution of decomposition gases, indicating that the catalysts substantially promote the decomposition process. Furthermore, beyond thermal decomposition, the Fe-doped carbon composites also significantly improved the combustion characteristics of DAP-4. “High-speed combustion imaging and infrared thermal measurements revealed that catalyst-containing samples ignite more rapidly and burn more intensely than pristine DAP-4,” says Chen.
Among all formulations, Fe-Carbon-3 exhibits the shortest combustion duration together with the highest combustion temperature and heat release. The researchers attributed this superior performance to the synergistic interaction between highly dispersed FeOx nanoparticles and conductive carbon substrates.
“While the carbon framework participates in oxidation–reduction reactions, the FeOx nanoparticles efficiently catalyzed hydrogen transfer and accelerate the redox reactions between the fuel cations and perchlorate oxidizer, leading to faster energy release and more vigorous combustion,” says Chen.
Based on their results, the researchers proposed a catalytic mechanism in which FeOx nanoparticles facilitate hydrogen transfer from ammonium and protonated DABCO cations to perchlorate anions during heating. “This process accelerated the formation of reactive intermediates and promoted rapid decomposition, ultimately resulting in earlier ignition and enhanced combustion performance,”says Chen.
“Our findings provide valuable guidance for the development of high-performance combustion catalysts and offer new opportunities for improving the ignition behavior, energy-release efficiency, and practical application of advanced molecular perovskite energetic materials,” adds lead author Yi-ming Wang.
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Contact author details:
National Key Laboratory of Solid Rocket Propulsion, Northwestern Polytechnical University, Xi'an, 710072, China. E-mail address: asierchen@nwpu.edu.cn (S.-l. Chen).
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Energetic Materials Frontiers
Enhanced thermal decomposition and combustion performance of energetic molecular perovskite DAP-4 catalyzed by Fe-doped carbon composites
The authors Yue-wen Wang is employed by Shanxi Jiangyang Chemical Co., Ltd., Taiyuan. The other authors declare that they have no competing interests and there is no financial interests which may be considered as potential competing interests.