Introduction

Ammonium perchlorate (NH4ClO4, AP) is an effective oxidizer for composite propellants due to its high oxygen balance and gaseous decomposition nature [1,2,3]. AP usually accounts for 60–90 mass% of composite propellant. AP thermal decomposition process greatly influenced by the combustion characteristics of composite propellants [4, 5]. AP decomposition is the key factor for composite propellant combustion. AP particle size, and pyrolysis temperature could significantly impact the burning rate, as well as the ignition delay time. Besides, the increase in AP decomposition enthalpy can boost the specific impulse [6, 7]. Therefore, catalyzed AP decomposition can enhance the ballistic characteristics of composite propellants. AP decomposition undergoes two main steps including:

  • Low temperature decomposition (LTD), with the evolution of HClO4(g) and NH3 (g).

  • High temperature decomposition (HTD), where final gaseous products are evolved [8,9,10].

Accelerating AP decomposition with the release of enormous amount of heat is appreciated for enhanced propellant performance [11, 12]. Different transition metal oxides, such as Fe2O3[13, 14], CuO [15, 16], MnO2 [17], Co3O4 [4, 18, 19], and ZnO [9, 20], and binary metal oxides, such as ZnCo2O4 [21], CuCr2O4 [22, 23], NiFe2O4 [24], and CdCo2O4 have been adopted to catalyze AP decomposition [25]. Transition metal oxides (typical semiconductors) can secure rich electron transfer orbitals in the redox reaction cycle; thus, they could support electron transfer reactions [26]. For instance, they can facilitate the transfer of electrons from ClO −4 to NH +4 with the evolution of superoxide ions ( i. e., O −2 )[27]. Co3O4 exhibits high theoretical capacitance of 3560 F g−1[28]. Co3O4 has wide catalytic applications such as crude fuel cracking [29], selective removal of carbon monoxide [30], waste gas treatment [31], oxidation of cyanides [32], decomposition of NO [33], Li-ion battery [34], and gas sensors [35]. Manganese based oxides can experience variety of reactions due to wide range manganese oxidation states (Mno, Mn+2, Mn+3, and Mn+4). Consequently, manganese is candidate for many applications, including energy storages [36], magnetic materials [37], sensors [38], and catalysis [39]. It is widely accepted that ion doping can enhance the electrochemical performance and surface area [40]. Facile ion doping in a mild synthesis condition is promising platform that can be adopted to avoid sophisticated procedures [41]. Improving the thermal decomposition of AP is imperative to strengthen the performance of the rocket propellant. Many different catalysts have been applied to accelerate the thermal decomposition of AP. Mn@Co3O4 catalyst has demonstrated high performance; it secured high heat release, and decreased activation energy. Consequently, doping Co3O4 with manganese can secure novel catalytic performance for AP decomposition. In the current study, Mn@Co3O4 porous microspheres, with large surface areas, were prepared via solvothermal synthesis in ethylene glycol solvent with subsequent annealing treatment. Mn@Co3O4 microspheres with uniform diameter were assembled exhibiting a BET-specific surface area of 73.5 m2 g−1 and a pore volume of 0.293 cm3 g−1. Thermal behavior of Mn@Co3O4/AP nanocomposite was evaluated to pure AP using DSC and TGA. Mn@Co3O4 offered an increase in AP decomposition enthalpy by 86.6%. Additionally Mn@Co3O4 decreased the main decomposition temperature by 143 °C. Mn@Co3O4 demonstrated spectacular change in AP thermal behavior. Mn@Co3O4 catalyst demonstrated decrease in AP apparent activation energy by 16% for HTD decomposition. Upon AP decomposition, NH3 could accumulate on AP surface and could render the proton transfer process; this process could inhibit further AP decomposition. Porous Mn@Co3O4 microspheres could adsorb released NH3 gases and could act as active site for oxidation of ammonia with perchloric acid. This superior catalytic effect could withstand the surge in AP decomposition enthalpy from 836 J g−1 to 1560 J g−1. The porous Mn@Co3O4microspheres demonstrated prominent catalytic features for AP thermal decomposition.

Experimental

Synthesis of Mn@Co3O4 microspheres

Homogenous solution was developed by dissolving Mn(CH3COO)2.4H2O (1mmol) and Co(CH3COO)2.4H2O (2 mmol) in 40 mL ethylene glycol solvent. Consequently, 20 mmol of urea was introduced, the resultant solution was loaded into 50 mL autoclave, sealed, and reacted at 190 °C for 15 h. Black powder was produced from the pink precursor by annealing for five hours at 600 °C (4 °C min−1) (Supplementary Figure S1). Mn@Co3O4 was treatment with 20% volume of NH3 at 300 °C to investigate the effect of NH3 on the catalytic reaction of AP. FTIR was employed to evaluate the catalytic action of Mn@Co3O4 for NH3 gas adsorption.

Integration of Mn@Co3O4 into AP

Mn@Co3O4 particles were re-dispersed in acetone using ultrasonic probe homogenizer. Subsequently, AP was dissolved in acetone colloid. The content of Mn@Co3O4 was limited to 1 mass%. Mn@Co3O4 was integrated into AP via anti-solvent (Dichloromethane) re-precipitation of AP in the presence of Mn@Co3O4 (Supplementary Figure S2).

Characterization of Mn@Co3O4, and Mn@Co3O4/AP nanocomposite

SEM, ZEISS SEM EVO 10 MA with EDAX detector, was used to analyze the size and shape of the generated Mn@Co3O4, and to assess the dispersion of Mn@Co3O4 into AP. Shape and size of Mn@Co3O4 particles were characterized by TEM (JEM-2100F by Joel Corporation). Crystalline structure of Mn@Co3O4 was investigated using a HiltonBrooks X-ray diffractometer, over 2Ө from 5 to 65 degrees. Brunauere-Emmette-Teller-specific surface area and pore diameter analyzer (BET, quantachrome Autosorb 1-C) operated at 77 K. Chemical structure of Mn@Co3O4 was investigated using infrared spectroscopy using JASCO spectrometer model 4100 (Japan).

Thermal behavior of Mn@Co3O4 /AP nanocomposite

Decomposition temperature and decomposition enthalpy of Mn@Co3O4/AP nanocomposite was investigated via DSC Q200 by TA, USA; the tested sample was heated to 500 °C at 10 °C min−1 under a 50-mL min−1 N2 flow. Mass loss with temperature was investigated via TGA 55 by TA; the tested sample was heated to 500 °C at 10 °C min−1 under a flow of nitrogen 50 mL min−1.

Decomposition kinetics of Mn@Co3O4 /AP nanocomposite

The significant impact of Mn@Co3O4 on AP decomposition kinetics was evaluated using different analysis models including isoconversional (model free) and model fitting [42, 43]. Decomposition kinetics of Mn@Co3O4/AP composite was assessed using TGA. The mass loss of tested sample was recorded at different heating rates 4, 6, 8 and 10 °C·min−1 for Mn@Co3O4/AP and pure AP. The general form of the basic kinetic equation can be written as.

$$\frac{{{\text{d}}\alpha }}{{{\text{d}}t}} = A{\text{e}}^{{ - \frac{{\text{E}}}{{{\text{RT}}}}}} f\left( \alpha \right)$$
(1)

Where α, t, A, E, T, R, and f(α) are the conversion degree (dimensionless), time (s), frequency factor (s−1), activation energy (J/mol), absolute temperature (K), universal gas constant (8.314 J K−1 mol−1), and differential conversion function, respectively. Under non-isothermal conditions at a constant heating rate, (Eq. 1) can be expressed by Eq. (2):

$$\frac{{{\text{d}}\alpha }}{{{\text{d}}T}} = \frac{A}{\beta }{\text{e}}^{{ - \frac{{\text{E}}}{{{\text{RT}}}}}} f\left( \alpha \right)$$
(2)

Where β is the heating rate (K s−1). Isoconversional kinetic methods under constant heating rate conditions are based on the following assumptions:

  • The rate of reaction is influenced by temperature and the extent of conversion.

  • The heating rate has no effect on kinetic parameters.

  • Isoconversional calculations should be conducted at constant conversions.

The assumptions, restrictions, and deviations of the FWO and KAS methods can be found in the corresponding literature [44]. The equations for the FWO and KAS methods are given below.

$${\text{FWO}}:~\ln \beta_{{\text{i}}} = \ln \left( {\frac{{A\alpha ~E\alpha }}{{Rg\left( \alpha \right)}}} \right) - 5.331 - 1.052\frac{{E\alpha }}{{RT\upalpha ,{\text{i}}}}$$
(3)
$${\text{KAS: }}\ln \left( {\frac{{\beta_{\text{i}} }}{{T_{{\upalpha ,{\text{i}}}}^{{1.92}} }}} \right) = {\text{Const}} - 1.0008\frac{{E\alpha }}{{RT\alpha }}$$
(4)

The Friedman differential isoconversional method can be derived by the linearization of (Eq. 2) with a series of heating rates.

$${\text{Friedman}}~~\ln \left[ {\beta _{i} \left( {\frac{{{\text{d}}\alpha }}{{{\text{d}}T}}} \right)_{{T_{{\upalpha ,{\text{i}}}} }} } \right] = \ln \left( {A_{\upalpha } f\left( \alpha \right)} \right) - \frac{{E\alpha }}{{RT_{{\upalpha ,{\text{i}}}} }}$$
(5)

New modified Friedman isoconversional method has been proposed, on the basis of the numerical calculation theory [45].

$$\left( {\frac{{{\text{d}}\alpha }}{{{\text{d}}T}}} \right)_{{T_{{\upalpha ,{\text{i}}}} }} \approx \left( {\frac{{\Delta \alpha }}{{\Delta T}}} \right)_{{T_{{\upalpha ,{\text{i}}}} }} = \frac{{\Delta \alpha }}{{T_{{\upalpha + \Delta \upalpha /2,{\text{i}}}} - ~T_{{\upalpha - \Delta \upalpha /2,{\text{i}}}} }}$$
(6)

With the substitution of (Eq. 5) into (Eq. 6), the Modified Friedman (Eq. 7) is obtained.

$${\text{Modified}}\;{\text{Friedman~}}\;\ln \left[ {\beta _{{\text{i}}} \frac{{\Delta \alpha }}{{T_{{\upalpha + \frac{{\Delta \upalpha }}{2},{\text{i}}}} - ~T_{{\upalpha - \frac{\alpha }{2},\text{i}}} }}} \right] = \ln \left( {A_{\upalpha } f\left( \alpha \right)} \right) - \frac{{E\alpha }}{{RT_{{\upalpha ,{\text{i}}}} }}$$
(7)

Kinetic parameters (Ea, A) can be obtained via the drawings \({\text{ln}}{\upbeta }_{\mathrm{I}}\) vs 1000/Tα,i, \(\mathrm{ln}\left(\frac{{\upbeta }_{\mathrm{i}}}{{\mathrm{T}}_{\mathrm{\alpha },\mathrm{i}}^{1.92}}\right)\) vs 1000/Tα,i, and \(\mathrm{ln}\left[{\upbeta }_{\mathrm{i}}\frac{\Delta \alpha }{{T}_{\upalpha +\frac{\Delta \upalpha }{2},{\text{i}}}- {T}_{\upalpha -\frac{\Delta \upalpha }{2},{\text{i}}}}\right]\) vs 1000/Tα,i; where the slope is the effective activation energy (Ea) and the intercept is the frequency factor (A). Activation energy (Ea) of developed Mn@Co3O4/AP nanocomposite was evaluated from Kissinger’s model (Eq. 8)[46, 47], Where Ea, β, Tp, and R are the activation energy, heating rate, decomposition temperature and universal gas constant, respectively. To get the slope – Ea/R from ln(β/Tp2) against (1/Tp).

$$- \frac{{Ea}}{R} = \frac{{{\text{d}}~\ln \left( {\beta /T_{{\text{p}}}^{2} } \right)}}{{{\text{d}}\left( {1/T_{{\text{p}}} } \right)}}$$
(8)

Results and discussion

Characterization of Mn@Co3O4 and Mn@Co3O4/AP composite

Morphology of Mn@Co3O4 nanoparticles was investigated by HRTEM prior to calcinations process. TEM micrographs demonstrated high quality mono-dispersed particles of 15 nm particle size (Fig. 1).

Fig. 1
figure 1

TEM micrographs of Mn@Co3O4 prior to calcinations

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Morphology of calcinated Mn@Co3O4 particles was investigated by SEM; SEM micrographs demonstrated Mn@Co3O4 microspheres with 5 µm in diameter (Fig. 2a and b). Microspheres could be assembled via numerous nanoparticles with the evolution of porous structure. The average particle size distribution of Mn@Co3O4 microspheres was 5.5 nm (Fig. 3C).

Fig. 2
figure 2

SEM micrograph of Mn@Co3O4 (a, b), particle size distribution of Mn@Co3O4 (c)

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Fig. 3
figure 3

SEM micrograph of Mn@Co3O4 (a), EDX mapping images for Co (b), Mn (c), and O (d)

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Elemental mapping was conducted via EDX detector. Uniform dispersion of main Mn@Co3O4 elements (cobalt, manganese, and oxygen) was verified (Fig. 3).

The XRD pattern of the Mn@Co3O4 demonstrated cubic crystalline Co3O4 (JCPDS 01–074- 1656)[48,49,50]. There were no diffraction peaks-related manganese oxides in the XRD pattern. Elemental manganese could be doped within Co3O4 crystal structure [51]. The lattice parameter “a” was found to be 8.1106 Å; this value is larger than pure Co3O4 (8.064 Å). The increase in lattice parameters was related to the incorporation of Mn+2. The radius of Mn+2 (0.066 nm) is larger than Co+3 (0.0545 nm), and Co+2 (0.065 nm) [52]. MnCo3O4 demonstrated lattice spacing of 0.48 nm corresponds to the (111) planes; this value is larger than the theoretical value of pure Co3O4 (0.4667 nm). This finding confirmed that Mn+2 ions, with a larger radius, was effectively doped into Co3O4 crystal structure. Doping Mn+2 into Co3O4 crystal could withstand the shift of XRD peaks to the lower angles. Porous Mn@Co3O4 microspheres were actually assembled from numerous nanoparticles (NPs); porous Mn@Co3O4 structure can secure high surface area (Fig. 4).

Fig. 4
figure 4

XRD diffractogram of synthesized Mn@Co3O4 microspheres

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The N2 adsorption/desorption was adopted to retrieve pore-size distribution curves at 77 K. The curve have exhibited type-H3 hysteresis loop, which are typical mesoporous structure. The BET specific surface area was evaluated to be 73.7 m2 g−1 and a pore volume 0.271 cm3 g−1 (Fig. 5a). The pore size was distributed narrowly at 13.1 nm with a mean pore diameter of 16 nm based on BJH model (Fig. 5b).

Fig. 5
figure 5

N2 adsorption–desorption isotherms (a), and the relative BJH pore-size distribution of the Mn@Co3O4 (b)

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The mesoporous structure and large BET specific surface area could secure superior catalytic effect for AP decomposition. Colloidal Mn@Co3O4 particles were integrated into AP using anti-solvent technique; this approach can secure uniform particle dispersion. SEM was adopted to visualize the morphology of Mn@Co3O4/AP nanocomposite, whereas pure AP demonstrated 200–250 μm average-sized spheres (Fig. 6a). AP nanocomposite revealed ultra-fine particles of 10 μm average particle size (Fig. 6b).

Fig. 6
figure 6

SEM micrograph of pure AP (a), and Mn@Co3O4/AP composite (b)

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Element mapping was adopted to assess the catalyst dispersion within AP matrix. Main catalyst elements (Mn, Co) were mapped via EDAX detector (Fig. 7).

Fig. 7
figure 7

Elemental mapping of Mn@Co3O4/AP nanocomposite using EDX detector

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Thermal behavior of Mn@Co3O4/AP nanocomposite.

The catalytic effect of Mn@Co3O4 microspheres on AP decomposition was investigated via DSC. Pure AP demonstrated endothermic phase change at 243 °C, with consequent two exothermic decomposition peaks at 298 and 453 °C. Pure AP demonstrated total decomposition enthalpy of 836 J g−1 [53]. Mn@Co3O4/AP nanocomposite experienced one exothermic decomposition peak at 310 °C, with an increase in AP decomposition enthalpy by 86.6% (Fig. 8).

Fig. 8
figure 8

Thermal behavior of AP, and Mn@Co3O3/AP nanocomposite using DSC

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AP initial decomposition could start with proton transfer between ammonium ion and perchloric ion, with the evolution of NH3 and HClO4 [53,54,55]. HClO4 is unstable under the reactive temperature and most of the HClO4 could easily leave the surface of AP crystal before oxidizing adsorbed NH3 [56]. Thus, NH3 could accumulate on AP surface and hinder the proton transfer process; consequently, it could inhibit further AP decomposition. Porous Mn@Co3O4 microspheres could adsorb released NH3 gases and could act as active site for oxidation of ammonia with perchloric acid. This superior catalytic effect could withstand the surge in AP decomposition enthalpy from 836 J g−1 to 1560 J g−1. The catalytic effect of Mn@Co3O4 on AP thermal decomposition was further investigated using TGA (Fig. 9).

Fig. 9
figure 9

TGA curves of AP (a), and Mn@Co3O4/AP composite (b)

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Mn@Co3O4 catalysts decreased the main AP exothermic decomposition temperature from 453 °C to 310 °C. This a dramatic decrease in AP thermal decomposition by 143 °C confirmed the advanced catalytic effect of Mn@Co3O4. The catalytic action of Mn@Co3O4 for NH3 gas adsorption was investigated via FTIR. Mn@Co3O4 was thermal treated at 300 °C under 20% volume of NH3. FTIR spectra of pure Mn@Co3O4 and thermally treated Mn@Co3O4 are demonstrated in Fig. 10. Pure Mn@Co3O4 demonstrated two peaks at 662 cm−1 and 567 cm−1; these peaks were correlated to Co–O bonds in Co3O4. The broad peak at 3100:3600 cm−1 and the weak peak at 1630 cm−1 were correlated to the stretching and flexural vibration of adsorbed H2O, respectively.

Fig. 10
figure 10

FTIR spectra of Mn@Co3O4 before and after thermal treatment under NH3

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Thermally treated Mn@Co3O4 catalyst demonstrated two peaks at 1373 cm−1 and 1487 cm−1; such peaks could be correlated to the formation of Co–N–O structures on crystal surface after thermal treatment under NH3 gas [57, 58]. FTIR outcomes confirmed the catalytic effect of Mn@Co3O4 on adsorption of NH3 from the surface of the AP. Figure 11 demonstrates a schematic for the catalytic effect of Mn@Co3O4 on AP decomposition via NH3 gas adsorption.

Fig. 11
figure 11

Catalytic mechanism of Mn@Co3O4 on AP decomposition

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Mn@Co3O4 demonstrated the highest catalytic effect for AP decomposition compared with common catalyst as represented in Table 1.

Table 1 The impact of different catalysts on AP decomposition
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Mn@Co3O4 demonstrated decrease in AP main exothermic temperature to 310 °C; furthermore, it offered decomposition enthalpy of 1560 J g−1 compared with 836 J g−1 for pure AP.

Thermocatalytic degradation mechanism

Thermocatalytic degradation mechanism of catalyzed AP was investigated using TGA analysis (Fig. 12). Linear heating rate experiments were conducted under different heating rates.

Fig. 12
figure 12

TGA curves of pure AP (a), and Mn@Co3O3/AP nanocomposite (b), at different heating rates

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According to the sets of α (the conversion rate)-T plots (Fig. 13); a series of kinetic triplets can be obtained via the isoconversional pathways (FWO, KAS, and Friedman Equations).

Fig. 13
figure 13

α-T curves of AP-LTD (a), AP-HTD (b), and Mn@Co3O3/AP composite (c) with different heating rates

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The \(\mathrm{ln}{\upbeta }_{\mathrm{i}}\) vs 1000/Tα,i, \(\mathrm{ln}\left(\frac{{\upbeta }_{\mathrm{i}}}{{\mathrm{T}}_{\mathrm{\alpha },\mathrm{i}}^{1.92}}\right)\) vs 1000/Tα,i, and \(\mathrm{ln}\left[{\upbeta }_{\mathrm{i}}\frac{\Delta \alpha }{{T}_{\upalpha +\frac{\Delta \upalpha }{2},{\text{i}}}- {T}_{\upalpha -\frac{\Delta \upalpha }{2}, {\text{i}}}}\right]\) vs 1000/Tα,I curves corresponding to FWO, KAS, and Friedman models over the range of α = 0.05 ~ 0.9, with a step size of 0.05, are demonstrated in Fig. 14.

Fig. 14
figure 14

Global kinetic profiles of the pure AP-LTD, AP-HTD, and Mn@Co3O4/AP nanocomposite

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For AP-HTD and AP-LTD, FWO and KAS isoconversional plots demonstrated similar tendencies. Consequently, similar Ea values from the slopes corresponding to the straight lines. Ea values obtained by Friedman equation differed from those obtained from the FWO and KAS equations; this is demonstrated by the trends of the global kinetic plots (Fig. 15).

Fig. 15
figure 15

Ea vs. α curves of AP-LTD (a), AP-HTD (b), and Mn@Co3O4/AP composite (c)

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Mn@Co3O4/AP nanocomposite demonstrated similar Ea value using Friedman, FWO, and KAS models, respectively. Eα values of AP-HTD, Mn@Co3O4/AP obtained from FWO, and KAS methods different changes with α; this behavior indicated multiple decomposition pathways. AP-HTD demonstrated an increase in Eα with increase in α up to α = 0.55, subsequently Eα was decreased with increase in α up to α = 0.95. AP-LTD demonstrated decrease in Ea till α = 0.25; then Ea increased till α = 0.55 and begin to be similar with FWO, and KAS methods (Table 2) [63, 64].

Table 2 Kinetic parameters for AP-LTD, AP-HTD, and Mn@Co3O4/AP composite
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The Eα values of Mn@Co3O4/AP nanocomposite by the Friedman was found to be 149.7 ± 2.54 kJ mol−1 compared with 173.16 for AP-HTD. Mn@Co3O4/AP presented the most distinguishing decrease in activation energy, revealing the potential catalytic activity of Mn@Co3O4 on AP decomposition. This catalytic effect could withstand the increase in AP decomposition enthalpy from 836 J g−1 to 1560 J g−1. Ea was evaluated for pure AP and Mn@Co3O4/AP nanocomposite via Kissinger model (Fig. 16).

Fig. 16
figure 16

Activation energy of AP-LTD (a), AP-HTD (b), and Mn@Co3O4/AP composite (c) using Kissinger method

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Ea values using Kissinger were evaluated to FWO, KAS, and Friedman models. Ea values are more closely to Friedman method for both AP-HTD, and AP-LTD and less closely to FWO, and KAS methods. The common pyrolysis mechanism functions and the corresponding model relationships are represented in Fig. 17 [65].

Fig. 17
figure 17

The reaction mechanisms of the two samples at each stage using CR method

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The curve whose vertical coordinate \(\ln \left( {\frac{\beta }{{T^{2} }}} \right)\) and horizontal coordinate (1/T) is plotted to obtain the curve fitness R2, and the model corresponding to the best R2 is the final pyrolysis reaction model determined by CR method (Eq. 9), and (Supplementary Table T1).

$$\ln \left( {\frac{{g(\alpha )}}{{T^{2} }}} \right) = \ln \left( {\frac{{AR}}{{\beta E_{\alpha } }}} \right) - \frac{{E_{\alpha } }}{{RT}}$$
(9)

where g(α) is the integral version of the pyrolysis reaction mechanism function f(α), the relationship is shown in (Eq. 10)

$$g\left(\alpha \right)= {\int }_{0}^{\alpha }f\left(\alpha \right)= \frac{A}{\beta }{\int }_{{T}_{O}}^{T}exp\left(\frac{{E}_{\alpha }}{RT}\right){\text{d}}T= \frac{AE}{\beta R}P\left(\frac{{E}_{\alpha }}{RT}\right)$$
(10)

The kinetic decomposition models for pure AP, and Mn@CO3O4/AP nanocomposite were investigated via CR method. Pure AP demonstrated two decomposition stages. The kinetic model for the AP-LTD was a third reaction model (F3), while for the AP-HTD the reaction model was (A2), which known as random nucleation followed by two dimensional random nucleation and nucleus growth models. Mn@Co3O4/AP nanocomposite demonstrated one decomposition stag; the reaction model was changed to (A3) known as random nucleation followed by three dimensional random nucleation and nucleus growth (Table 3).

Table 3 Decomposition models for pure AP and Mn@O4/AP nanocomposite at each decomposition stage
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It was verified that the catalyst Mn@Co3O4 changed the mechanism of pure AP decomposition by eliminating LTD stage and change the HTD stage model from (A2) to (A3) model.

Conclusions

Mn@Co3O4 nanoparticles of 15 nm size were developed via solvothermal synthesis. Porous Mn@Co3O4 microspheres were developed via controlled annealing process at 600 °C. Mn@Co3O4 microspheres exhibited a BET-specific surface area of 73.7 m2 g−1 and a main pore-size distribution at 13.1 nm. Mn@Co3O4 microspheres secured an increase in AP decomposition enthalpy by 86.6% using DSC. Furthermore, Mn@Co3O4 microspheres decreased AP main decomposition temperature by 143 °C. The significant impact of Mn@Co3O4 microspheres on AP kinetic decomposition was investigated via isoconversional analysis-based FWO, KAS, Friedman, and Kissinger method. Mn@Co3O4/AP nanocomposite experienced decrease in AP activation by 23.46 kJ mol−1. This advanced catalytic effect was ascribed to the active surface sites as well as the high capability to adsorb NH3 gas on the catalyst surface. This superior catalytic effect can secure high reaction propagation rate.