Superparamagnetic energetic nanoparticles: a surface self-propagation pathway for the thermal decomposition of ammonium perchlorate

In this work, our research group developed usable low-cost superparamagnetic nanoparticles (Fe 3 O 4 @NTA) that behave as an excellent energetic material to accelerate the thermal decomposition of ammonium perchlorate (AP). As a synthetic strategy, magnetite nanoparticles (Fe 3 O 4 ) were coated with nitrilotriacetic acid (NTA) by a simple preparation method. Based on High-resolution transmission electron microscopy (HR-TEM) and vibrating sample magnetometer (VSM) results, Fe 3 O 4 @NTA presents a mean diameter of 7.4 nm and superparamagnetic behavior. Chemical characterization by Energy-dispersive X-ray spectroscopy (XPS), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) provided enough evidence for the presence of a carboxylic acid group and magnetite in the sample. The Fe 3 O 4 @NTA catalyst diminishes AP high-temperature decomposition (HTD) to 342 °C and shows a low activation energy (98.02 kJ mol −1 ). In addition, after the burning rate test, it was observed that these resulting nanoparticles showed an adequate magnetic response against an external magnet. These results are promising for future research, as the opportunity opens to reuse this functional magnetic material in successive catalytic cycles, thus contributing soon to the recycling of raw materials necessary for interplanetary travel. Graphical abstract