A strategy for modulating the catalytic active center of AP thermal decomposition and its application: La-doped MgCo2O4

Abstract

The active center of the nanomaterial is one of the main factors affecting the catalytic decomposition of ammonium perchlorate (AP), but the underlying mechanism is still not clear. In this study, we successfully replaced parts of the tetrahedral sites of MgCo₂O₄ with the rare earth metal element La using a one-step solution combustion synthesis method and exposed more Co³⁺ active centers to investigate its effect on the catalytic performance of AP. At higher Co³⁺/Co²⁺ ratios, La1%-MgCo₂O₄ caused a striking reduction in the T_HTD of AP by 215.16 °C, indicating the effect of the active center on the catalytic decomposition of AP. The successful doping of the impurity atom La also significantly enhanced the electrical conductivity of MgCo₂O₄ and accelerated the electron transfer process in AP thermal decomposition. More importantly, the ammonia oxidation reaction proceeds rapidly under the combined effect of La³⁺, O₂⁻, high Co³⁺ concentration, and high electrical conductivity, leading to a quick pyrolysis of AP. In addition, the introduction of La1%-MgCo₂O₄ significantly shortens the ignition delay time (from 47 ms to 18 ms) of AP-based composite solid propellants (CSPs) and provides a new idea for the design of AP-based CSPs.