Ultrathin MCo2O4(M = Fe, Ni, Cu and Cr) Nanosheets/Carbon heterostructures for highly efficient thermal decomposition of ammonium perchlorate

Transition metal oxides exhibit inherent catalytic activity for ammonium perchlorate (AP) decomposition; however, their performance is limited by the scarcity of accessible active sites and low conductivity. Therefore, morphology-directed structural design and interfacial engineering are highly desirable. In this study, two-dimensional (2D) MCo 2 O 4 nanosheets ( M = Fe, Ni, Cu, and Cr) were synthesized via a thermal expansion method and subsequently combined with three types of carbon materials C x (C x = rGO, CNTs, and g-C 3 N 4 ) to construct 2D MCo 2 O 4 /C x composites. Structural analyses demonstrate that the intimate interfacial coupling between 2D MCo 2 O 4 nanosheets and carbon materials effectively suppresses restacking and establishes a continuous conductive network. More importantly, strong interfacial coupling enables effective electronic modulation at the heterojunction, resulting in an optimized charge distribution and enhanced interfacial electron transfer. Among all catalysts, 5 wt. % FeCo 2 O 4 /rGO-1 demonstrates the most notable catalytic activity for AP decomposition, reducing its peak temperature in the high-temperature decomposition stage by 137.4 °C and increasing its heat release by 736.33 J·g⁻ 1 . Electrochemical tests confirm that accelerated interfacial charge transfer enhances AP pyrolysis. Kinetic modelling, TG-FTIR-MS, and DFT calculations indicate that the 2D-2D heterointerface boosts the adsorption of the AP intermediate NH 3 and promotes its conversion into higher-valence NO 2 , while also accelerating electron transport and lowering the decomposition barrier. The synergistic effect between interfacial electron transport and the heterojunction promotes the rapid AP degradation. Based on these findings, a plausible catalytic mechanism for AP decomposition is proposed.