Vacuum freeze-drying-assisted synthesis of spinel ferrite/CNTs for enhanced catalytic thermal decomposition of KClO4

Potassium perchlorate (KClO 4 ), as a vital energetic oxidizer, has its application in propellants and other fields limited by its inherently high decomposition temperatures. To overcome this limitation, this study employs a freeze-drying-assisted assembly strategy to successfully synthesize ferrite/carbon nanotube (MFe 2 O 4 /CNTs, M = Cu, Co, Ni) composites. Material characterization techniques, including SEM, XRD, and XPS, confirmed the morphology, crystal structure, elemental chemical states, and surface oxygen speciation. Differential thermal analysis demonstrated that the prepared composites significantly reduce the thermal decomposition temperature of KClO 4 and substantially decrease the activation energy. Among them, CoFe 2 O 4 /CNTs exhibited the optimal catalytic performance, lowering the decomposition temperature from 615.4 to 492.6 ℃ at a heating rate of 10 ℃ min −1 . Mechanism analysis via the reaction function Z(α) revealed that the decomposition of pure KClO 4 follows a three-dimensional nucleation and growth mechanism (Avrami–Erofeev model). In contrast, the introduction of CoFe 2 O 4 /CNTs shifts the rate-controlling step to a three-dimensional diffusion mechanism (D3 model), indicating that the catalyst reshapes the decomposition pathway by accelerating the diffusion of gaseous intermediates. The enhanced catalytic performance originates from multiple synergistic effects: the redox activity of the spinel structure, the activation of oxygen species by surface oxygen vacancies, and the accelerated electron transport facilitated by the three-dimensional conductive network constructed by the CNTs. Furthermore, combustion tests of the energetic material confirmed that incorporating 3 mass% CoFe 2 O 4 /CNTs catalyst shortened the combustion time by 57.2%, expanded the flame propagation area, increased the combustion temperature, and led to a more stable combustion profile.