Enhanced catalytic behavior of La2O2CO3/Co3O4 composite for thermal decomposition of ammonium perchlorate

In this work, La2O2CO3, Co3O4 and La2O2CO3/Co3O4 composites were prepared by one-step solution combustion with citric acid as oxidant and lanthanum nitrate and cobalt nitrate as reductants. Morphology analysis showed many pores of different sizes on the surface of the composite. The best catalytic performance was for the La2O2CO3/Co3O4 composite. The high-temperature decomposition (HDT) of ammonium perchlorate (AP) decreased by 187.7 degrees C, and the activation energy decreased from 371.6 to 140.6 kJ mol-1. The combustion process of AP/hydroxyl-terminated polybutadiene solid propellant containing La2O2CO3/Co3O4 was more intense, the ignition delay time was shortened from 30 to 25 ms and the time to reach maximum combustion effect was advanced from 370 to 190 ms. Through the mechanism analysis, we believe that the adsorption of NH3 by La2O2CO3 promotes AP decomposition and also causes breakage of N-H bonds, which accelerates the oxidative decomposition of NH3. The Co3O4 has unfilled 3d orbitals, which could accelerate electron transfer during the reaction. At the same time, the interface between the two substances leaks more active sites, further accelerating electron transfer. Therefore, La2O2CO3/Co3O4 composites are expected to be widely used in solid propellants.

Automated summary

La2O2CO3, Co3O4, and La2O2CO3/Co3O4 composites were prepared through one-step solution combustion method using citric acid as oxidant and lanthanum nitrate and cobalt nitrate as reductants. The La2O2CO3/Co3O4 composite exhibited the best catalytic performance. It significantly reduced the decomposition temperature and activation energy of ammonium perchlorate (AP) and improved the combustion efficiency of AP/hydroxyl-terminated polybutadiene solid propellant. The mechanism analysis revealed that the adsorption of NH3 by La2O2CO3 and the unfilled 3d orbitals of Co3O4 played crucial roles in promoting the decomposition of AP and accelerating electron transfer.