Room-temperature preparation of Cu/Zn bimetallic MOFs and their efficient catalysis for the thermal decomposition of ammonium perchlorate

In this study, copper acetate, zinc acetate, and 1,3,5-benzenetricarboxylic acid (H 3 BTC) were used as raw materials to successfully prepare Cu-BTC, Zn-BTC, and Cu/Zn molar ratio 1:1, 2:1, and 1:2 Cu–Zn bimetallic metal-organic frameworks (MOFs) via a simple and low-energy room-temperature stirring method. MOFs/AP composite particles were subsequently prepared using a mechanical grinding and mixing method. The influence of them as catalysts on the thermal decomposition of ammonium perchlorate (AP) was systematically studied. Characterization methods like FTIR, XRD, SEM, and TEM validated the materials' structure and morphological features and showed that the Cu/Zn ratio modifies the MOFs’ microscopic morphology. DSC and TG analyses demonstrated that Cu–Zn-BTC (Cu:Zn = 2:1) exhibited excellent catalytic performance even at a low additive amount of only 2%. This catalyst markedly decreased the high-temperature decomposition peak of AP to 297.50 °C while simultaneously enhancing the heat release during decomposition to 1070 J/g. Furthermore, the apparent activation energy was substantially reduced from 216.26 kJ/mol observed for pristine AP to 127.45 kJ/mol. A longitudinal comparison showed that AP catalyzed by Cu–Zn-BTC (2:1) possessed the lowest thermal decomposition peak temperature, outperforming both Cu-BTC/AP (311.00 °C) and Zn-BTC/AP (334.80 °C). Furthermore, it exhibited the highest heat release and the lowest activation energy. Therefore, the synergistic effect between Cu and Zn in the bimetallic MOFs enhanced their catalytic performance, which was significantly superior to that of single-metal MOFs. This work provides important enlightenment for the design of AP-based propellant high efficiency catalyst.