The B-Site Position Modulates the Catalytic Activity of Lamo3 Perovskite, Thereby Enhancing the Thermal Decomposition Performance of Ammonium Perchlorate

Abstract

ABO3-type perovskite oxides are widely used in fields such as electrocatalysis and photocatalysis due to their advantages of easy synthesis, low cost, and high thermal stability. As catalytic materials, perovskites can catalyze both oxidation and reduction reactions. The thermal decomposition process of AP involves a significant number of redox reactions, yet there is limited research on the use of perovskite catalysts for AP decomposition. In this study, LaMO3 (M = Co, Fe, Al) perovskite catalysts were synthesized via the sol-gel method to investigate the differences in band gap values and electrical conductivity resulting from the substitution of different B-site elements. The catalytic mechanisms of AP thermal decomposition were then analyzed based on these properties. The results show that LaCoO3 exhibits exceptional catalytic performance. The addition of LaCoO3 reduced the decomposition temperature of AP from 473.1°C to 323°C, lowered the activation energy from 418.2 kJ/mol to 156.3 kJ/mol, and increased the heat release from 88.8 J/g to 942.5 J/g. A series of characterizations, including XPS, DFT, EIS and UV-vis were performed on the three catalysts. The results revealed that the perovskite catalysts with smaller band gaps exhibited stronger electron transfer capabilities and better catalytic performance, thus providing an explanation for the differences in catalytic activity among the materials.

Keywords: Ammonium perchlorate, perovskite catalytic materials, Catalytic thermal decomposition, solid propellants