Embedding of ferrocenes in the nanochannels of manganese energetic coordination polymers to retard their migration trends and enhance their catalytic efficiency in the thermal degradation of ammonium perchlorate

Pronounced migration tendency of the ferrocene-based burning rate catalysts (FcR-BRCs) often compromises the combustion performance of prolonged stored composite solid propellants. Herein, FcR@MnECPs composites were constructed by encapsulating commercial FcR-BRCs within the nanochannels of nitrogen-rich manganese energetic coordination polymers (MnECPs) to retard FcR-BRCs migration. The morphologies and structures of the FcR@MnECPs composites were characterized by SEM, TEM, XPS, XRD, Raman and BET. Migration tests displayed negligible migration of the Cat@MnECPs (Cat = catocene) composites in pseudo-propellants at 50 degrees C. The electrochemical analysis verified that the filling of catocene in the MnDAT (DAT = 3,5-diamino-1,2,4-triazole) mesoporous cavity accelerated the electron transfer of MnDAT. Catalytic tests for ammonium perchlorate (AP) pyrolysis revealed 5 wt% Cat@MnDAT advances the high-temperature decomposition peak of AP by 98.8 degrees C and increases its heat release by 1.15 times. The XRD and XPS analysis confirmed the formation of Mn2O3-Fe2O3 heterojunction in AP catalytic disintegration. The thermal decomposition kinetics, TG-FTIR-MS, and theoretical calculations elucidated that the catalytic degradation pathway of AP with Cat@MnDAT and MnDAT as catalysts: The Mn2O3-Fe2O3 heterojunction expedites the electron transfer (promoting O2- generation) and boosts the conversion of AP into higher oxidation state nitrogen oxides. Finally, a plausible catalytic combustion mechanism for AP is proposed.