Unravelling the reaction mechanism for the AP decomposition over MgO: A density functional theory study and microkinetic simulation

Abstract

The detailed reaction mechanisms for the decomposition of ammonium perchlorate (AP), an essential component of solid composite propellants, are poorly understood due to the ultrafast and complex reactions. Density functional theory and kinetic simulation are utilized to calculate the decomposition reaction of AP on the surface of magnesium oxide and present a detailed decomposition network. Using a proton transfer mechanism, NH3 and HClO4 are the major production at low-temperature decomposition of AP, involving two elementary steps. AP is completely decomposed in the high-temperature reaction stage. In this work, it is found that the decomposition of NH3 is mainly in the form of oxidative dehydrogenation, while HClO4 proceeds along the pathway HClO4→ClO3→ClO2→ClO→Cl, and the final nitrogen oxides, chlorine oxides are formed. These simulations provide offer atomic-level understanding of the complex reaction kinetics of AP, which can be applied to explore the reaction mechanisms of other metal oxides.