The Built-in Electric Field in Bimetallic System Promotes the Efficient Thermal Decomposition of Ammonium Perchlorate

The thermal decomposition performance of ammonium perchlorate (AP) in solid propellants directly affects the energy output and combustion efficiency of propulsion systems. However, its relatively high decomposition temperature and dispersed exothermic behavior limit its practical application. In this work, a CeO₂/Co₃O₄-based catalyst with a three-dimensionally ordered macroporous (3DOM) structure was constructed and evaluated for the thermal decomposition of AP. Using the template assisted method, 3DOM CeO₂/xCo₃O₄ (3DCe/xCo) catalysts with tunable Co²⁺/Ce³⁺ ratios were prepared and their catalytic behaviors toward AP decomposition were systematically investigated. Among them, 3DCe/0.9Co exhibited the best catalytic activity, lowering the high temperature decomposition temperature of AP by about 30% and markedly reducing the activation energy. Structural characterization, UV-vis DRS, VB-XPS, TG-IR, TG-MS, in situ XPS, and DFT calculations indicate that electron transfer from Co₃O₄ to CeO₂ generates a built-in electric field and oxygen vacancies, which promote side-selective adsorption and activation of NH₃ and HClO₄. The interconnected 3DOM framework also facilitates mass transport and conversion of AP intermediates, and finally merges the two decomposition peaks of AP into a single exothermic peak. This work provides additional insight into the role of interfacial charge transfer and 3DOM CeO₂/Co₃O₄ catalysts for AP thermal decomposition.