Two-dimensional metal oxide composite reduced graphene oxide burning rate catalyst

Abstract

The invention discloses a two-dimensional metal oxide composite reduced graphene oxide burning rate catalyst, which is prepared by the following steps: uniformly grinding glucose, ammonium nitrate and transition metal nitrate, calcining at high temperature to generate a two-dimensional metal oxide nanosheet, mixing the two-dimensional metal oxide nanosheet with surfactant modified reduced graphene oxide powder, and sintering at high temperature to obtain the two-dimensional metal oxide composite reduced graphene oxide burning rate catalyst. And transferring into a high-pressure hydrothermal kettle for solvothermal reaction, so that the reduced graphene oxide and the two-dimensional metal oxide nanosheet are compounded to form the composite burning rate catalyst with a 2D-2D structure. Two two-dimensional materials are compounded through a solvothermal method, the defects of accumulation of reduced graphene oxide and aggregation of the two-dimensional metal oxide due to high surface energy are effectively avoided, meanwhile, the high conductivity of the reduced graphene oxide is utilized, the synergistic catalysis effect of the metal oxide and the carbon material is enhanced, and the performance of the composite material is improved. The composite material has a good catalytic effect on the thermal decomposition process of ammonium perchlorate.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid propellants, and particularly relates to a burning rate catalyst of two-dimensional metal oxide composite reduced graphene oxide. Background Art

[0002] Solid propellants are special energetic materials that provide power for missiles, rockets, space vehicles, etc., and are composed of (modified) double-base propellants and (modified) composite solid propellants. Among them, composite propellants play an important role in various weapons such as rockets and missiles because of their relatively simple manufacturing and processing technology and relatively free design of charge diameter adjustment. Composite solid propellants are energetic materials prepared from multiple components such as binders, oxidizers, high-energy fuels, combustion performance regulators, plasticizers, stabilizers / anti-aging agents, and bonding agents, and have the advantages of high energy density, excellent mechanical properties, relatively simple processing process, and good safety performance, thus playing an important role in various weapons such as rockets and missiles. Combustion performance regulators are also called burning rate catalysts. Generally, burning rate catalysts are added to solid propellants to adjust the burning rate of the propellants and reduce the pressure index, so that the burning rate temperature sensitivity coefficient within a certain temperature range is reduced, and the comprehensive performance of the solid propellants is further improved. Therefore, adding burning rate catalysts to solid propellants is a very effective means.

[0003] Graphene has attracted a great deal of research due to its unique two-dimensional structure, large surface area, good electrical conductivity, high mechanical strength, light weight, and structural flexibility. In particular, chemically prepared reduced graphene oxide nanosheets are widely used as effective carrier carbon materials. In the preparation of catalysts, graphene can act as a dispersant to effectively inhibit the aggregation of nanoparticles. At the same time, the synergistic effect between graphene and nanoparticles will further enhance the catalytic performance of the catalyst. In recent years, a lot of attention has been paid to reduced graphene oxide-supported catalysts. Zhao Fengqi et al. prepared the rGO@Fe2O3 composite by atomic layer deposition (ALD). Fe2O3 nanoparticles were uniformly fixed on the rGO nanosheets through surface chemical interactions, realizing the uniform dispersion of densely packed Fe2O3 nanoparticles. Compared with Fe2O3 nanoparticles without carrier support, the spatial distribution of the composite material was improved, and the number of active sites increased. The research results showed that as a catalyst, the peak temperature of the high-temperature decomposition of ammonium perchlorate (AP) by rGO@Fe2O3 (212%) was greatly reduced compared with that of Fe2O3 without carrier support, indicating that rGO as a carrier effectively inhibited the aggregation of Fe2O3 nanoparticles (Ning Yan, Lijun Qin, Jianguo Li, Fengqi Zhao, HaoFeng. Atomic layer deposition of iron oxide on reduced graphene oxide and its catalytic activity in the thermal decomposition of ammonium perchlorate[J]. Applied Surface Science. 2018, 451: 155-161).

[0004] Nanoscale metal oxides are traditional burning rate catalysts. Especially transition metal oxide materials (TMOs), which are abundant in nature and widely distributed, have become a research hotspot today. Due to the lattice defects and hole electrons in the crystal, metal oxides provide a large number of active sites for reactions. These reactive sites can strongly adsorb oxidants and their decomposition products, thus accelerating the combustion and decomposition of propellants. However, these nanoscale metal oxide catalysts are prone to aggregate into large particles due to their high surface energy, and it is difficult to control the size of their nanoparticles, resulting in a significant reduction in specific surface area, thus reducing the catalytic effect on energetic materials. To avoid aggregation, a special method is to construct a hierarchical structure, that is, a uniform assembly of nanomaterials. Research has confirmed that this hierarchical structure can effectively maintain the size effect of the nanocomposite structure. Its secondary structure can serve as a supporting substrate, with the dual advantages of both anti-aggregation and enhanced stability, and both of these are key factors affecting catalytic activity. Zhang Wenchao et al. prepared MnCo2O 4.5Vertically anchored on reduced graphene oxide, a hierarchical porous structure is formed. The introduction of reduced graphene oxide significantly increases the conductivity and specific surface area of the material, effectively avoiding the aggregation of MnCo2O 4.5 nanoparticles and the re-stacking of graphene. The research results show that the synergistic effect between MnCo2O 4.5 nanoparticles and reduced graphene oxide can promote the capture and transfer of electrons. The rGO / MnCo2O 4.5 composite material makes the low-temperature decomposition peak of AP disappear, the high-temperature decomposition temperature is reduced by 124.1 °C, and the reaction rate is 186.8 times that of pure AP (Zilong Zheng, Wenchao Zhang, Liang Chen, Wenhui Xiong, Guowei Zeng, Jiaqi Liu, Runhui Wu, Jiaxin Wang, Jiahai Ye, Junwu Zhu, In-situ synthesis of MnCo2O 4.5 nanosheets on reduced graphene oxide for a great promotion in the thermal decomposition of ammonium perchlorate[J]. Applied Surface Science. 2019, 483: 496-505).

[0005] Therefore, reduced graphene oxide has attracted much attention due to its large specific surface area, stable structure and good conductivity. As an efficient carrier, it has good development prospects in the field of combustion catalysis. In addition, metal oxides have good stability and many catalytic active sites. By adjusting the thickness of metal oxides in the longitudinal direction to the nanoscale to form two-dimensional layered materials, more surface active sites are exposed, the electron transport channel is shortened, and the specific surface area of metal oxides is increased, in order to achieve better catalytic effects. However, due to the surface energy, two-dimensional layered metal oxides are prone to stacking and aggregation, resulting in a decrease in the specific surface area of the composite material. Research shows that combining it with carbon materials can form a stable structure and a synergistic catalytic effect, which has an obvious catalytic effect in the field of combustion. Summary of the Invention

[0006] The object of the present invention is to provide a two-dimensional metal oxide composite reduced graphene oxide burning rate catalyst with relatively low cost and simple preparation. The reduced graphene oxide and two-dimensional metal oxide nanosheets are combined by a solvothermal method to form a stable 2D-2D structure. The high conductivity and good mechanical properties of the reduced graphene oxide are utilized to enhance the synergistic catalytic effect and electron transfer rate between the metal oxide and the carbon material, thereby increasing the catalytic effect on AP.

[0007] The two-dimensional metal oxide composite reduced graphene oxide burning rate catalyst provided by the present invention is prepared by the following method: the two-dimensional metal oxide nanosheets and reduced graphene oxide are added to a solvent and ultrasonically dispersed, and then transferred to a high-pressure hydrothermal autoclave for solvothermal reaction. The obtained precipitate is centrifuged, washed, and vacuum dried to obtain the burning rate catalyst.

[0008] The above two-dimensional metal oxide nanosheets are any one of Co3O4, Cr2O3, NiO, Fe2O3, and CuO.

[0009] Further, it is preferably that the mass ratio of the two-dimensional metal oxide nanosheets to the reduced graphene oxide is 1:0.5 - 3.

[0010] The preparation method of the above two-dimensional metal oxide nanosheets is: glucose, ammonium nitrate, and metal nitrate are put into a ball mill and ground evenly, and then calcined in a high-temperature muffle furnace to form two-dimensional porous metal oxide nanosheets. It is preferably that the mass ratio of glucose, ammonium nitrate, and metal nitrate is 4:5:0.2 - 1, the rotation speed of the ball milling is 1200 - 3000 rmp, the ball milling time is 4 - 8 h, the calcination temperature is 450 - 650 °C, the time is 10 - 60 min, and the calcination atmosphere is air.

[0011] The above reduced graphene oxide is obtained by reacting graphene oxide treated with hydrazine hydrate and a surfactant. The surfactant is any one of poly(diallyldimethylammonium chloride), polyvinylpyrrolidone, and cetyltrimethylammonium bromide.

[0012] Further, it is preferably that the solvent is a mixture of isopropanol and deionized water with a volume ratio of 0.5 - 2:1.

[0013] Further, it is preferably that the temperature of the solvothermal reaction is 80 - 120 °C and the time is 4 - 15 h.

[0014] Further, it is preferably that the temperature of the vacuum drying is 60 - 80 °C and the time is 8 - 20 h.

[0015] The preparation method of the two-dimensional porous transition metal oxide in the present invention is as follows: Glucose, ammonium nitrate, and metal nitrate are put into a ball mill and ground evenly, and then calcined in a high-temperature muffle furnace to form a two-dimensional porous metal oxide. Among them, the mass ratio of glucose, ammonium nitrate, and metal nitrate is preferably 4:5:0.2-1; the rotation speed of the ball milling is preferably 1200-3000 rmp, the ball milling time is 4-8 h, the calcination temperature is 450-650 °C, the time is 10-60 min, and the calcination atmosphere is air.

[0016] The beneficial effects of the present invention are as follows:

[0017] 1. In the present invention, two-dimensional metal oxide nanosheets and reduced graphene oxide are compounded by a solvothermal method, and the longitudinal scale of the metal oxide is controlled at the nanometer level, so that more surface active sites are exposed. Moreover, the reduced graphene oxide used is surface-modified with a surfactant, enabling it to be better dispersed in water. In addition, the interaction between the surfactant and graphene can functionalize graphene, which helps to further load two-dimensional metal oxide nanosheets. Compounding it with two-dimensional metal oxide nanosheets increases the specific surface area and electron transfer rate of the composite burning rate catalyst, thereby improving the catalytic efficiency.

[0018] 2. The two-dimensional transition metal oxide and reduced graphene oxide adopted in the present invention itself have good combustion catalytic performance. The composite material of the two has the electrical conductivity of carbon materials and the stability of metal oxides, greatly improving the "synergistic catalytic effect" of reduced graphene oxide and two-dimensional transition metal oxide, thereby improving the combustion catalytic performance for AP.

[0019] 3. The preparation method of the two-dimensional metal oxide composite reduced graphene oxide burning rate catalyst in the present invention is simple, low in cost, environmentally friendly, and can be mass-produced. Description of the Drawings

[0020] Figure 1 It is a scanning electron microscope image of reduced graphene oxide in Example 1.

[0021] Figure 2 It is a scanning electron microscope image of two-dimensional Co3O4 nanosheets in Example 1.

[0022] Figure 3 It is a scanning electron microscope image of the two-dimensional Co3O4 nanosheet composite reduced graphene oxide burning rate catalyst prepared in Example 1.

[0023] Figure 4 It is a differential scanning calorimetry analysis curve of adding 5 wt.% of the burning rate catalysts prepared in Examples 1-5 and pure AP to AP respectively.

[0024] Figure 5They are the differential scanning calorimetry curves of AP with 5 wt.% of the burning rate catalysts prepared in Comparative Examples 1-6 and pure AP added respectively.

[0025] Figure 6 They are the differential scanning calorimetry curves of AP with 5 wt.% of the burning rate catalysts prepared in Examples 1, 6, 7, and 8 and pure AP added respectively.

[0026] Figure 7 They are the differential scanning calorimetry curves of AP with 5 wt.% of the reduced graphene oxide, two-dimensional Co3O4 nanosheet composite reduced graphene oxide burning rate catalyst in Example 1, the burning rate catalyst in Comparative Example 1, and pure AP added respectively. Detailed implementation manners

[0027] The present invention will be further described in detail below in conjunction with the drawings and embodiments, but the protection scope of the present invention is not limited to these embodiments.

[0028] Example 1

[0029] 1 mL of polydiallyldimethylammonium chloride was added to 50 mL of 1 mg / mL graphene oxide aqueous solution, and ultrasonic dispersion was carried out for 2 h at a power of 720 W and a temperature of 20 °C. Then 0.3 mL of hydrazine hydrate was added and stirred at 500 rmp and 90 °C for 3 h, filtered and washed with deionized water. Then the obtained solid was dried in vacuum at 60 °C to obtain reduced graphene oxide, denoted as rGO. It can be seen that the prepared reduced graphene oxide has a wrinkled two-dimensional sheet structure on the surface, is transparent in some areas, and the edges show a wavy or curly morphology, indicating good flexibility. Figure 1 It can be seen that the prepared reduced graphene oxide has a wrinkled two-dimensional sheet structure on the surface, is transparent in some areas, and the edges show a wavy or curly morphology, indicating good flexibility.

[0030] 0.4 g of glucose, 0.5 g of ammonium nitrate, 0.02 g of Co(NO3)2·6H2O and 20 μL of deionized water were placed in an agate ball milling jar and ball milled at 2100 rmp for 6 h to obtain a uniform viscous precursor. Then the precursor was calcined in a muffle furnace, the calcination atmosphere was air, the calcination temperature was 500 °C, and the holding time was 20 min. Then it was immediately taken out and cooled to room temperature to obtain two-dimensional Co3O4 nanosheets. It can be seen that the prepared Co3O4 presents flexible and curly nanosheets, a two-dimensional nanoscale structure composed of uniform nanoparticles, the thickness of the nanosheets is distributed in the range of 20-40 nm, and the pore structure between particles can be seen in some areas, indicating that the material is a porous structure. Figure 2 It can be seen that the prepared Co3O4 presents flexible and curly nanosheets, a two-dimensional nanoscale structure composed of uniform nanoparticles, the thickness of the nanosheets is distributed in the range of 20-40 nm, and the pore structure between particles can be seen in some areas, indicating that the material is a porous structure.

[0031] 10 mg of two-dimensional Co3O4 nanosheets were added to 20 mL of isopropanol and ultrasonically dispersed for 20 min to obtain suspension A1. Then, 10 mg of rGO was added to 20 mL of deionized water and ultrasonically dispersed for 60 min to obtain suspension B1. Subsequently, suspension B1 was added to suspension A1 and ultrasonically mixed evenly. Then, the mixture was transferred to a 50 mL Teflon-lined autoclave for solvothermal reaction at 100 °C for 6 h. After the reaction, it was naturally cooled to room temperature, centrifuged at 10000 rmp, and the obtained solid was dried in vacuum at 80 °C for 6 h to obtain a two-dimensional Co3O4 nanosheet composite reduced graphene oxide burning rate catalyst, denoted as Co3O4 / rGO-1. From Figure 3 It can be seen that the reduced graphene oxide sheets are tightly combined with the Co3O4 nanosheets, without obvious gaps or serious stacking phenomena.

[0032] Example 2

[0033] In this example, two-dimensional Cr2O3 nanosheets were prepared according to the method of Example 1, and an equal amount of two-dimensional Cr2O3 nanosheets was used to replace the two-dimensional Co3O4 nanosheets in Example 1. The specific steps and conditions were the same as those in Example 1, and a two-dimensional Co3O4 nanosheet composite reduced graphene oxide burning rate catalyst was prepared, denoted as Cr2O3 / rGO.

[0034] Example 3

[0035] In this example, two-dimensional NiO nanosheets were prepared according to the method of Example 1, and an equal amount of two-dimensional NiO nanosheets was used to replace the two-dimensional Co3O4 nanosheets in Example 1. The specific steps and conditions were the same as those in Example 1, and a two-dimensional NiO nanosheet composite reduced graphene oxide burning rate catalyst was prepared, denoted as NiO / rGO.

[0036] Example 4

[0037] In this example, two-dimensional Fe2O3 nanosheets were prepared according to the method of Example 1, and an equal amount of two-dimensional Fe2O3 nanosheets was used to replace the two-dimensional Co3O4 nanosheets in Example 1. The specific steps and conditions were the same as those in Example 1, and a two-dimensional Fe2O3 nanosheet composite reduced graphene oxide burning rate catalyst was prepared, denoted as Fe2O3 / rGO.

[0038] Example 5

[0039] In this example, two-dimensional CuO nanosheets were prepared according to the method of Example 1, and an equal amount of two-dimensional CuO nanosheets was used to replace the two-dimensional Co3O4 nanosheets in Example 1. The specific steps and conditions were the same as those in Example 1, and a two-dimensional CuO nanosheet composite reduced graphene oxide burning rate catalyst was prepared, denoted as CuO / rGO.

[0040] Comparative Example 1

[0041] 0.4 g of glucose, 0.5 g of ammonium nitrate, 0.02 g of Co(NO3)2·6H2O and 20 μL of deionized water were placed in an agate ball milling jar, and ball milled at a rotation speed of 2100 rmp for 6 h to obtain a uniform viscous precursor. Then the precursor was calcined in a muffle furnace. The calcination atmosphere was air, the calcination temperature was 500 °C, and the heat preservation time was 20 min. Subsequently, it was immediately taken out and cooled to room temperature to obtain a two-dimensional Co3O4 nanosheet burning rate catalyst.

[0042] Comparative Example 2

[0043] 10 mg of two-dimensional Co3O4 nanosheets prepared in Comparative Example 1 and 10 mg of rGO prepared by the method of Example 1 were placed in an agate mortar and ground evenly to obtain a mechanically mixed two-dimensional Co3O4 nanosheet composite reduced graphene oxide burning rate catalyst.

[0044] Comparative Example 3

[0045] Co(NO3)2·6H2O in Comparative Example 1 was replaced with Cr(NO3)3·6H2O, and the other steps were the same as those in Comparative Example 1 to obtain a dark green fluffy solid, that is, a two-dimensional Cr2O3 nanosheet burning rate catalyst.

[0046] Comparative Example 4

[0047] Co(NO3)2·6H2O in Comparative Example 1 was replaced with Ni(NO3)2·6H2O, and the other steps were the same as those in Comparative Example 1 to obtain a gray fluffy solid, that is, a two-dimensional NiO nanosheet burning rate catalyst.

[0048] Comparative Example 5

[0049] Co(NO3)2·6H2O in Comparative Example 1 was replaced with Fe(NO3)3·9H2O, and the other steps were the same as those in Comparative Example 1 to obtain a reddish-brown fluffy solid, that is, a two-dimensional Fe2O3 nanosheet burning rate catalyst.

[0050] Comparative Example 6

[0051] Co(NO3)2·6H2O in Comparative Example 1 was replaced with Cu(NO3)2·6H2O, and the other steps were the same as those in Comparative Example 1 to obtain a black fluffy solid, that is, a two-dimensional CuO nanosheet burning rate catalyst.

[0052] Example 6

[0053] In Example 1, 10 mg of two-dimensional Co3O4 nanosheets were added to 20 mL of isopropanol and ultrasonically dispersed for 20 min to obtain suspension A1. Then, 5 mg of rGO was added to 20 mL of deionized water and ultrasonically dispersed for 60 min to obtain suspension B1. Subsequently, suspension B1 was added to suspension A1, and after ultrasonic mixing to uniformity, it was transferred to a 50 mL Teflon-lined autoclave for solvothermal reaction at a reaction temperature of 100 °C for 6 h. After the reaction, it was naturally cooled to room temperature, centrifuged at 10000 rmp, and the obtained solid was vacuum dried at 80 °C for 6 h to obtain a two-dimensional Co3O4 nanosheet composite reduced graphene oxide burning rate catalyst, denoted as Co3O4 / rGO-0.5.

[0054] Example 7

[0055] In Example 1, 10 mg of two-dimensional Co3O4 nanosheets were added to 20 mL of isopropanol and ultrasonically dispersed for 20 min to obtain suspension A1. Then, 20 mg of rGO was added to 20 mL of deionized water and ultrasonically dispersed for 60 min to obtain suspension B1. Subsequently, suspension B1 was added to suspension A1, and after ultrasonic mixing to uniformity, it was transferred to a 50 mL Teflon-lined autoclave for solvothermal reaction at a reaction temperature of 100 °C for 6 h. After the reaction, it was naturally cooled to room temperature, centrifuged at 10000 rmp, and the obtained solid was vacuum dried at 80 °C for 6 h to obtain a two-dimensional Co3O4 nanosheet composite reduced graphene oxide burning rate catalyst, denoted as Co3O4 / rGO-2.

[0056] Example 8

[0057] In Example 1, 10 mg of two-dimensional Co3O4 nanosheets were added to 20 mL of isopropanol and ultrasonically dispersed for 20 min to obtain suspension A1. Then, 30 mg of rGO was added to 20 mL of deionized water and ultrasonically dispersed for 60 min to obtain suspension B1. Subsequently, suspension B1 was added to suspension A1, and after ultrasonic mixing to uniformity, it was transferred to a 50 mL Teflon-lined autoclave for solvothermal reaction at a reaction temperature of 100 °C for 6 h. After the reaction, it was naturally cooled to room temperature, centrifuged at 10000 rmp, and the obtained solid was vacuum dried at 80 °C for 6 h to obtain a two-dimensional Co3O4 nanosheet composite reduced graphene oxide burning rate catalyst, denoted as Co3O4 / rGO-3.

[0058] To prove the effective effect of the present invention, 5 wt.% of reduced graphene oxide, the burning rate catalysts prepared in Comparative Examples 1-6, and the five two-dimensional metal oxide composite reduced graphene oxide burning rate catalysts prepared in Examples 1-8 were respectively added to AP for combustion catalytic performance testing, and the results are shown in Figures 4 to 6 .

[0059] FromFigure 4 It can be seen that when 5 wt.% of the two-dimensional metal oxide composite reduced graphene oxide burning rate catalysts prepared in Examples 1 to 5 was added to the main component AP of the solid propellant, the high-temperature decomposition peak of AP advanced from 417.1 °C to 293.9 °C, 312.9 °C, 326.1 °C, 328.9 °C, and 320.4 °C respectively, decreasing by 123.2 °C, 104.2 °C, 91.0 °C, 88.2 °C, and 96.7 °C respectively. The heat release of AP increased from 739.39 J·g -1 to 1512.95 J·g -1 、1543.06 J·g -1 、1718.89 J·g -1 、1619.80 J·g -1 、1598.49 J·g -1 respectively, increasing by 773.56 J·g -1 、803.67 J·g -1 、979.5 J·g -1 、880.41 J·g -1 、859.1 J·g -1 respectively. Among them, Co3O4 / rGO had the largest advance in the high-temperature decomposition peak for the thermal decomposition catalysis of AP and a relatively large heat release. In addition, it can be found from the peak shape that its heat release was more concentrated. After adding 5 wt.% of the two-dimensional metal oxide composite reduced graphene oxide burning rate catalysts prepared in Examples 1 to 5, the high-temperature decomposition stage of AP showed a phenomenon of concentrated heat release, and the heat release increased significantly, indicating that the burning rate catalyst of the present invention has a good combustion catalytic effect on the thermal decomposition of AP.

[0060] From Figure 5 it can be seen that under the same conditions, when 5 wt.% of the two-dimensional metal oxide burning rate catalysts prepared in Comparative Examples 1, 3, 4, 5, and 6 was added to the main component AP of the solid propellant, the high-temperature decomposition peak of AP advanced. Among them, the two-dimensional Co3O4 nanosheet had the largest advance in peak temperature. The high-temperature decomposition peak of AP advanced from 417.1 °C to 302.5 °C, and the heat release increased from 739.39 J·g -1 to 1420.41 J·g -1 ,increasing by 681.02 J·g -1 . When 5 wt.% of the mechanically mixed two-dimensional Co3O4 nanosheet composite reduced graphene oxide burning rate catalyst prepared in Comparative Example 2 was added to the main component AP of the solid propellant, the high-temperature decomposition peak of AP advanced to 318.3 °C, and the heat release increased by 928.85 J·g -1, it can be clearly seen from the DSC curve that the exothermic peak becomes wider and the exotherm is not concentrated. The physical mixture does not achieve the ideal composite effect. The ability to catalyze AP is such that the peak temperature of the combustion rate catalyst of two-dimensional Co3O4 nanosheets composite reduced graphene oxide prepared by the solvothermal method in Example 1 is shifted 24.4 °C backward, and the peak temperature is shifted 15.8 °C backward compared with that of the two-dimensional Co3O4 nanosheets in Comparative Example 1, indicating that mechanical grinding destroys the original two-dimensional structure of the oxide, resulting in a poor catalytic effect.

[0061] From Figure 6 it can be seen that under the same conditions, when 5 wt.% of the combustion rate catalysts of two-dimensional Co3O4 nanosheets composite reduced graphene oxide prepared in Examples 1, 6, 7, and 8 are added to the main component AP of the solid propellant, the high-temperature decomposition peak of AP is advanced from 417.1 °C to 293.9 °C, 297.6 °C, 297.4 °C, and 325.6 °C respectively, with decreases of 123.2 °C, 119.5 °C, 119.7 °C, and 91.5 °C respectively. The heat release of AP increases from 739.39 J·g -1 to 1512.95 J·g -1 , 1431.51 J·g -1 , 1602.81 J·g -1 , and 1816.25 J·g -1 respectively, with increases of 773.56 J·g -1 , 692.12 J·g -1 , 863.42 J·g -1 , and 1076.86 J·g -1 . The results show that as the rGO content in the combustion rate catalyst increases, the heat release gradually increases, and the amount of peak temperature decrease shows a trend of first increasing and then decreasing, among which Co3O4 / rGO-1 has the highest relative catalytic activity for AP.

[0062] From Figure 7 it can be seen that under the same conditions, when 5 wt.% of the combustion rate catalyst of Example 1, reduced graphene oxide, and the combustion rate catalyst of Comparative Example 1 are added to the main component AP of the solid propellant, the high-temperature decomposition peak of AP is advanced from 417.1 °C to 293.9 °C, 341.1 °C, and 302.5 °C respectively, with decreases of 123.2 °C, 76 °C, and 114.6 °C respectively. The heat release of AP increases from 739.39 J·g -1 to 1512.95 J·g -1 , 1219.61 J·g -1 , and 1420.41 J·g -1 respectively, with increases of 773.56 J·g -1 , 480.22 J·g -1 , and 681.02 J·g -1。The catalytic effect of reduced graphene oxide and the burning rate catalyst of Comparative Example 1 is not as obvious as that of the burning rate catalyst of Example 1. This shows that the composite between reduced graphene oxide and two-dimensional Co3O4 nanosheets is not a simple mechanical mixture of the two, and the composite by the solvothermal method exerts the synergistic catalytic effect between the two.

Claims

1. A two-dimensional metal oxide composite-reduced graphene oxide burning rate catalyst, characterized in that: Disperse two-dimensional metal oxide nanosheets and reduced graphene oxide in a solvent by ultrasonic treatment, then transfer them into a high-pressure hydrothermal autoclave for solvothermal reaction. The obtained precipitate is centrifuged, washed, and dried under vacuum to obtain the burn rate catalyst.

2. The two-dimensional metal oxide composite reduced graphene oxide burning rate catalyst according to claim 1, wherein: The two-dimensional metal oxide nanosheets are any one of Co3O4, Cr2O3, NiO, Fe2O3, and CuO.

3. The two-dimensional metal oxide composite reduced graphene oxide burning rate catalyst according to claim 1 or 2, characterized in that: The preparation method of the two-dimensional metal oxide nanosheets is as follows: Grind glucose, ammonium nitrate, and metal nitrate evenly in a ball mill, and then calcine them in a high-temperature muffle furnace to form two-dimensional porous metal oxide nanosheets.

4. The two-dimensional metal oxide composite reduced graphene oxide burning rate catalyst according to claim 3, characterized in that: The mass ratio of glucose, ammonium nitrate, and metal nitrate is 4:5:0.2 - 1; the rotation speed of the ball milling is 1200 - 3000 rmp, the ball milling time is 4 - 8 h, the calcination temperature is 450 - 650 °C, the calcination time is 10 - 60 min, and the calcination atmosphere is air.

5. The two-dimensional metal oxide composite reduced graphene oxide burning rate catalyst according to claim 1, wherein: The reduced graphene oxide is obtained by reacting graphene oxide treated with hydrazine hydrate and a surfactant.

6. The two-dimensional metal oxide composite reduced graphene oxide burning rate catalyst according to claim 5, wherein: The surfactant is any one of poly(diallyldimethylammonium chloride), polyvinylpyrrolidone, and cetyltrimethylammonium bromide.

7. The two-dimensional metal oxide composite reduced graphene oxide burning rate catalyst according to claim 1, characterized in that: The mass ratio of the two-dimensional metal oxide nanosheets to the reduced graphene oxide is 1:0.5 - 3.

8. The two-dimensional metal oxide composite reduced graphene oxide burning rate catalyst according to claim 1, wherein: The solvent is a mixture of isopropanol and deionized water with a volume ratio of 0.5 - 2:

1.

9. The two-dimensional metal oxide composite-reduced graphene oxide burning rate catalyst according to claim 1, characterized in that: The temperature of the solvothermal reaction is 80 - 120 °C, and the time is 4 - 15 h.

10. The two-dimensional metal oxide composite-reduced graphene oxide burning rate catalyst according to claim 1, characterized in that: The temperature of the vacuum drying is 60 - 80 °C, and the time is 8 - 20 h.

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