Effect of copper chromite on ammonium perchlorate decomposition-A TGA-FTIR-MS and FE-SEM study

The effect of a copper chromite (CC) catalyst on the decomposition of ammonium perchlorate (AP) was investigated using thermo gravimetric analysis (TGA) in conjunction with Fourier transform infrared (FTIR) spectroscopy and electron ionization (EI) mass spectrometry (MS) of the evolved gases. To determine the activation energy of AP samples, the Kissinger–Akahira–Sunose iso-conversional method was used, which shed more light on the effect of copper chromite on both the low-temperature decomposition (LTD) and high-temperature decomposition (HTD) stages. The FTIR and mass spectra revealed species O₂, N₂O, Cl₂, NO₂, HCl, HNO₃, H₂O, ClO, HOCl, and m/z equal to 30. Using a CC catalyst, an increment in the species mole fraction was detected in the HTD stage for all the AP samples. After the catalyst was brought closer, especially when it was embedded with AP, significant changes were observed in the LTD stage as well. MS revealed the formation of new species such as HClO₄, ClO₄, HClO₃, and ClO₃ when CC is embedded in AP. Additionally, increased ClO₂ due to CC enhances the decomposition reactions near the subsurface. C-DTA proves that the effect in LTD is more due to exothermic decomposition reactions. Consequently, this overall increase in species generation leads to greater mass loss during the LTD stage decomposition. The accelerated path of NO₂ production for the pellet of mixed ammonium perchlorate and copper chromite, as well as Copper chromite embedded AP in the LTD stage, is attributed to the presence of ClO₂ and the oxidation of CC. These findings demonstrate that the presence of CC near AP causes aging, resulting in a decrease in burn rate over time. Understanding these results will aid in building a detailed chemical kinetic mechanism (DCKM) and open new avenues for researchers to use it wisely in the real world.