Effect of Metal Type in Ferrocene-Based Mono- and Bimetallic MOFs on the Thermal Decomposition of Ammonium Perchlorate

To develop high-efficiency catalysts for solid propellants, this study synthesized monometallic (FcHz-Co) and bimetallic (FcHz-CoNi, FcHz-CoPb) MOFs using a ferrocene-based ligand (FcHz). Ferrocene derivatives are classic combustion promoters for solid propellants, while MOFs optimize ferrocene dispersion and enrich active sites-key to enhancing catalytic performance. Infrared spectroscopy, SEM, and XPS characterizations showed FcHz forms stable MOFs via N (from -NH₂/C = N groups)-metal coordination, while the ferrocene moiety, core combustion-promoting group, remains intact. Metal electron affinity (EA) is the core factor regulating material properties: FcHz-CoNi (Co: 0.662 eV, Ni: 1.157 eV) has well-dispersed spherical morphology (50.1 m²/g specific surface area) and balanced electron distribution due to bimetallic EA synergy; FcHz-Co (Co: 0.662 eV) has cubic morphology with secondary performance (limited by single-metal EA); FcHz-CoPb (Pb: 0.356 eV) agglomerates (11.2 m²/g specific surface area) due to low EA and large Pb²⁺ radius, showing the poorest performance. Catalytic tests confirmed FcHz-CoNi optimally promotes AP thermal decomposition: it reduces AP’s high-temperature decomposition peak from 441 ℃ to 329 ℃, boosts heat release to 1887 J/g, and lowers apparent activation energy to 89.49 kJ/mol. This study provides support for new propellant catalyst design and proposes a targeted strategy centered on “metal EA matching”.