Increased formation of higher-valence nitrogen oxides: The catalytic effect of altered cobalt-loaded carbon on the thermal decomposition of ammonium perchlorate

Adding catalysts to regulate the thermal decomposition of ammonium perchlorate (AP) is an essential strategy for enhancing the combustion performance of propellants. In this study, a carbon-loaded Co catalyst system with gradually increasing numbers of dispersed active sites was constructed to investigate the specific role of the catalyst in the thermal decomposition of AP. Experimental results revealed that the presence of Co in the catalyst caused the two decomposition peaks of pure AP to merge into a single peak. Furthermore, compared to the high-temperature decomposition peak of pure AP, the merged peak exhibited a significant forward shift, with a temperature reduction of 95 °C. As the Co content in the catalyst increased, the decomposition peak temperature progressively decreased from 320 °C to 311 °C, highlighting the positive impact of increased active sites on AP decomposition. Furthermore, the addition of the catalyst resulted in a higher concentration of NO and NO2 in the decomposition products compared to pure AP. This suggests that the catalyst prevents the interruption of AP decomposition by NH3 adsorption and facilitates electron transfer during the decomposition process, leading to a more complete oxidation of NH3. The study also found that the Co contained in the catalyst became oxidized and played a key role in the reaction.