Electrochemical Synthesis of the Energetic Combustion Catalyst Co(BODN)·9H2O and Its Catalytic Effect on Ammonium Perchlorate Thermal Decomposition

Safe, efficient, and green synthetic energetic combustion catalysts are of great importance for the application of ammonium perchlorate (AP) in solid propellants. In this study, a novel, simple, efficient, and green electrochemical method for synthesizing energetic combustion catalysts was designed and implemented to successfully synthesize Co(BODN)·9H2O (BODN = [2,2'-bi{1,3,4-oxadiazole}]-5,5'-dinitramide), a novel energetic combustion catalyst. The target products were characterized via single-crystal X-ray diffraction, powder X-ray diffraction, Fourier transform infrared spectroscopy, optical microscopy, scanning electron microscopy, differential scanning calorimetry, and thermogravimetric analysis. Results reveal that Co(BODN)·9H2O crystallizes in the triclinic P1̅ space group and has a density of 1.836 g cm-3. The size of the Co(BODN)·9H2O crystal increases gradually with the increase in the reaction current and the prolongation of the reaction time, respectively. However, the change in reaction current and time does not affect the crystal form. In addition, with the increase in Co(BODN)·9H2O content, the peak temperature of high-temperature decomposition (HTD) and apparent activation energy of AP/Co(BODN)·9H2O gradually decrease, and the heat release during thermal decomposition gradually increases. The HTD peak temperature and apparent activation energy of AP/Co(BODN) 9H2O (10%) decrease by 97.9 °C and 94.2 kJ·mol-1, respectively, compared with those of pure AP, and the heat release during thermal decomposition increases by 1613 J·g-1. Furthermore, compared with those of the propellant containing pure AP, the burning rate and flame temperature of the propellant containing AP/Co(BODN)·9H2O (10%) increase by 8.15 mm s-1 and 458.44 °C, respectively. Real-time Fourier transform infrared spectroscopy reveals that CoO catalyzes the thermal decomposition of AP mainly by promoting electron transfer to accelerate the oxidation of NH3 and the conversion of N2O to NO. In brief, this work provides new insights into synthesizing energetic combustion catalysts. Moreover, Co(BODN)·9H2O synthesized through the electrochemical method exhibits considerable application prospects for improving the thermal and energy performance of AP and the combustion performance of propellants.

Gelatin-modified Mxene carbon aerogels for ammonium-perchlorate-catalyzed thermal decomposition

The assembly of 2D Ti3C2Tx nanosheets into 3D structures with orderable structure has great importance for their use as catalyst carriers. However, Ti3C2Tx nanosheets are prone to accumulate in aqueous solutions owing to the strong van der Waals forces between Ti3C2Tx nanosheet layers, degrading their chemical properties. Carbon aerogel (Ti3C2Tx/G/Co) with a 3D porous structure and cobalt as the active site was prepared by a simple co-assembly-freeze-drying-high-temperature carbonization method for application in catalysis of ammonium perchlorate.

Preparation of a Chitosan-Lead Composite Carbon Aerogel and Its Catalytic Thermal Decomposition Performance on Ammonium Perchlorate

Chitosan-lead (CS-Pb) carbon aerogels were prepared by ionic cross-linking and high-temperature carbonization using chitosan (CS) as the carbon precursor. The obtained carbon aerogels were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), and X-ray photoelectron spectroscopy (XPS). The obtained aerogels have a 3D structure and a large surface area, which can effectively prevent the agglomeration phenomenon of metals. Differential thermal analysis (DTA) was used to analyze the catalytic performance of a carbon aerogel for ammonium perchlorate (AP). The results showed that the CS-Pb carbon aerogel reduced the peak temperature of AP pyrolysis from 703.9 to 627.7 K. According to the Kissinger method calculations, the E_a of AP decomposition decreased about 27.2 kJ/mol. The TG data at different warming rates were analyzed by the Flynne-Walle-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods, which are two of the isoconversion methods, and the activation energies of AP and AP+CS-Pb-3.5 were calculated. Between the conversion degrees (α) of 0.1 and 0.9, the E_a values obtained by the two isoconversion methods are similar and have a certain match. Also, the two isoconversion methods confirm Kissinger's calculation. Finally, thermogravimetry-mass spectrometry (TG-MS) was used to monitor the gases generated during the thermal decomposition of the AP+CS-Pb-3.5 system in real time.

Gas–solid two-phase flow method for preparing trimesic acid series MOFs for catalytic thermal decomposition of ammonium perchlorate

The Zn–BTC, Co–BTC and Zn–Co–BTC series MOFs were prepared by using the GSF device and applied in the catalytic thermal decomposition of AP to change the high-temperature thermal decomposition peak of AP.