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The design and development of microscopic surface structures and surface defects of nanomaterials provide infinite possibilities for optimizing their catalytic activity. In this study, the microscopic surface structure of MgCo 2 O 4 was modified while introducing combustible porous defective carbon (PDC) in MgCo 2 O 4 by taking advantage of the incomplete decarbonization during solution combustion after the addition of biotemplates. The double-modified C x -MgCo 2 O 4 (x denotes the abbreviations of Reed, Cherry, Bougainvillea-spectabilis, Crab-apple-flower and Cotton: Re, Ch, Bs, Cf and Co) exhibited high activity in catalyzing the thermal decomposition of AP. Among them, C Co –MgCo 2 O 4 with the highest carbon defect level (I D / I G = 4.54) significantly optimized the thermal decomposition performance of AP. The addition of C Co –MgCo 2 O 4 ensured both the reduction of the AP thermal decomposition T HTD (From 473.48 °C to 258.17 °C) and the increase of the AP heat of decomposition (ΔH , From 888.26 J/g to 3669.38 J/g). The introduction of combustible defective carbon in C x -MgCo 2 O 4 not only provides favorable conditions for the electron transfer process, but also generates synergistic heat during the thermal decomposition of AP and optimizes its energy release behavior. Compared with MgCo 2 O 4 , C Co –MgCo 2 O 4 further accelerates the ignition (From 17 ms to 14 ms) of the composite solid propellants (CSPs) and ensures the energy release during combustion. [Display omitted] • One-step construction of porous structure of C–MgCo 2 O 4 in combination with biomimetic combustion. • Double modification of C–MgCo 2 O 4 microscopic surface structure, defects. • Combustible PDC offer unlimited possibilities for high energy release from AP decomposition. • PDC, MgCo 2 O 4 double active surface for catalytic AP thermal decomposition presents ultra-high activity. [ABSTRACT FROM AUTHOR]

Co 3 O 4 is an excellent catalyst for the thermal decomposition of ammonium perchlorate (AP) due to its spinel structure and more Co3+ as catalytically active sites. In this work, MCo 2 O 4 (M=Fe, Cu, Ni and Zn) with different Co species substituted with transition metal ion were prepared using triblock copolymer F127 as soft template by simple solvothermal and subsequent heat treatment. The porous MCo 2 O 4 samples have higher Co3+ / Co2+ ratio than Co 3 O 4 , and exhibits better catalytic performance for thermal decomposition of AP. Especially with the addition of FeCo 2 O 4 , the high decomposition temperature (HDT) of AP decreases by an amazing 196.25 °C, showing the most excellent catalytic performance. The activation energy (E a) decreases from 290.19 kJ·mol−1 for pure AP to 203.05 kJ·mol−1, while the reaction rate (k) increases from 0.499 s−1 to 1.699 s−1. Based on the electron transfer theory, the catalytic mechanism and active site of porous MCo 2 O 4 series cobaltate materials are discussed. The results show that the porous FeCo 2 O 4 not only has highest specific surface, but also has the highest Co3+/ Co2+ ratio, which suggest that the Co3+ on octahedral coordination sites is known as the catalytic active site for AP thermal decomposition. [Display omitted] • Ordered nanoporous MCo 2 O 4 (M=Fe, Cu, Ni and Zn) were successfully syntesized and substituted for the Co in Co 3 O 4. • The high Co3+ / Co2+ ratio and specific surface area of FeCo 2 O 4 provide higher catalytic activity and sites. • The kinetic parameters of AP thermal decomposition have been better optimized after adding porous FeCo 2 O 4. • The catalytic mechanism of porous FeCo 2 O 4 for thermal decomposition of AP is proposed. [ABSTRACT FROM AUTHOR]