A nanocomposite material with a 3DOM encapsulation structure and a preparation method thereof

Abstract

The present invention belongs to the technical field of three-dimensionally ordered macroporous materials. The present invention provides a nanocomposite material with a 3DOM encapsulation structure and a preparation method thereof. After impregnating a colloidal crystal template in a metal ion precursor solution, drying and calcining are sequentially carried out to obtain a 3DOM CoFe2O4 material; the 3DOM CoFe2O4 material is impregnated in an ammonium perchlorate solution and then freeze-dried to obtain a nanocomposite material with a 3DOM encapsulation structure; the colloidal crystal template is a polymethyl methacrylate colloidal crystal template or a polystyrene colloidal crystal template; the metal ion precursor solution contains iron nitrate, cobalt nitrate, citric acid and a solvent. The 3DOM CoFe2O4@AP prepared by the present invention significantly improves the electron transfer rate and catalytic activity, and the 3DOM CoFe2O4@AP with an encapsulation structure can be widely applied to fields such as solid propellants, aerospace and industrial catalysis.

Description

Technical Field

[0001] The present invention relates to the technical field of three-dimensional ordered macroporous materials, and particularly to a nanocomposite material with a 3DOM encapsulation structure and a preparation method thereof. Background Art

[0002] Three-dimensional ordered macroporous materials (3DOM) have become a promising catalyst for catalytic reactions due to their connected three-dimensional pore structure and good mass transfer efficiency. Special applications based on 3DOM-supported functional components and functional 3DOM materials can greatly reduce the molecular diffusion resistance, provide sufficient space for gas and solid particles to convect and transport, and thus effectively improve the catalytic efficiency. However, it is still challenging to use 3DOM as an encapsulation template to prepare nanocomposite materials.

[0003] Solid propellants, as the power source of rocket engines and missile engines, have a significant impact on the ballistic performance of missiles. Solid propellants mainly include composite solid propellants and double-base propellants, and are mainly composed of oxidants, binders, metal fuels, burning rate catalysts (BRCs), and curing agents. As is well known, ammonium perchlorate (AP) is the most widely used oxidant in solid rocket propellants, and its thermal decomposition characteristics have a significant impact on the overall combustion performance of the propellant. Therefore, the thermal decomposition behavior of AP is often used to evaluate the combustion behavior of composite propellants. However, current research mainly focuses on the preparation of burning rate catalysts or the control of the size of AP, and there are still huge challenges in unifying the two, which also means that the potential of the catalyst and the thermal decomposition efficiency of AP cannot be maximized.

[0004] Therefore, how to obtain a nanocomposite material that can not only improve the contact efficiency between AP and the 3DOM catalyst but also regulate the size of AP has become an urgent problem to be solved at present. Summary of the Invention

[0005] The purpose of the present invention is to provide a nanocomposite material with a 3DOM encapsulation structure and a preparation method thereof in order to overcome the deficiencies of the prior art.

[0006] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0007] The present invention provides a preparation method of a nanocomposite material with a 3DOM encapsulation structure, comprising the following steps:

[0008] 1) Immerse the colloidal crystal template in the metal ion precursor solution, and then sequentially perform drying and calcination to obtain 3DOMCoFe2O4 material;

[0009] 2) Immerse the 3DOM CoFe₂O₄ material in an ammonium perchlorate solution, and then obtain a nanocomposite material with a 3DOM encapsulation structure through freeze-drying.

[0010] The colloidal crystal template in step 1) is a poly(methyl methacrylate) colloidal crystal template or a polystyrene colloidal crystal template; the metal ion precursor solution contains iron nitrate, cobalt nitrate, citric acid, and a solvent.

[0011] Preferably, the poly(methyl methacrylate) colloidal crystal template or the polystyrene colloidal crystal template in step 1) is obtained by drying poly(methyl methacrylate) emulsion microspheres or polystyrene emulsion microspheres; the particle size of the poly(methyl methacrylate) emulsion microspheres or the polystyrene emulsion microspheres is independently 150 - 400 nm; the drying temperature is 40 - 80 °C, and the drying time is 6 - 10 h.

[0012] Preferably, in the metal ion precursor solution of step 1), the metal ions are cobalt ions and iron ions, the total concentration of the metal ions is 0.8 - 2 mol / L, the molar ratio of cobalt ions to iron ions is 1:0.5 - 2.5, and the molar ratio of the metal ions to citric acid is 1:0.5 - 2.0.

[0013] Preferably, the solvent in step 1) includes one or more of methanol, ethanol, ethylene glycol, and glycerol.

[0014] Preferably, the mass-volume ratio of the colloidal crystal template to the metal ion precursor solution in step 1) is 1 g:2.5 - 10 mL.

[0015] Preferably, the impregnation time in step 1) is 3 - 6 h, the drying temperature is 30 - 70 °C, and the drying time is 8 - 10 h.

[0016] Preferably, the calcination temperature in step 1) is 400 - 500 °C, the heat preservation time at the calcination temperature is 4 - 6 h, and the heating rate to the calcination temperature is 1 - 5 °C / min.

[0017] Preferably, the mass-volume ratio of the 3DOM CoFe₂O₄ material to the ammonium perchlorate solution in step 2) is 1 g:200 - 800 mL; the concentration of the ammonium perchlorate solution is 0.01 - 0.16 g / mL.

[0018] Preferably, the impregnation time in step 2) is 0.5 - 6 min; the freeze-drying temperature is -50 - -5 °C, and the freeze-drying time is 8 - 32 h.

[0019] The present invention also provides a nanocomposite material with a 3DOM encapsulation structure prepared by the preparation method described above.

[0020] The beneficial effects of the present invention include:

[0021] 1) The 3DOM CoFe2O4@AP with an encapsulation structure prepared by the method of the present invention has good stability and maintains good structure and properties below 100 °C. The method of the present invention uses a stable 3DOM CoFe2O4 skeleton as a template framework to construct macropores and greatly improve the specific surface area of the composite material, which is beneficial to improving the mass transfer efficiency.

[0022] 2) The 3DOM CoFe2O4@AP prepared by the present invention can expand AP into a two-dimensional nanometer thin film and a completely encapsulated microsphere, and construct a catalyst / AP interface, significantly improving the electron transfer rate and catalytic activity. The 3DOM CoFe2O4@AP with an encapsulation structure is widely used in the fields of solid propellants, aerospace, and industrial catalysis, etc.

[0023] 3) The metal components in the 3DOM CoFe2O4@AP prepared by the present invention have low cost, are easy to obtain, and are green and environmentally friendly. The processing equipment used for this composite material is simple and common, and there is no need to add expensive equipment. In addition, the preparation process is simple and controllable. Description of the Drawings

[0024] Figure 1 Image of the PMMA colloidal crystal template prepared in Example 1;

[0025] Figure 2 SEM and TEM images of the 3DOM CoFe2O4 material prepared in Example 1, where a is the SEM image and b is the TEM image;

[0026] Figure 3 SEM images of 3DOM CoFe2O4@AP with different AP contents, where a is the AP mass fraction of 20 - 40%, b is the AP mass fraction of 60 - 80%, and c is the AP mass fraction ≥ 90%;

[0027] Figure 4 SEM and EDS images of the 3DOM CoFe2O4@AP prepared in Example 1;

[0028] Figure 5 TG and DSC images of the 3DOM CoFe2O4@AP prepared in Example 1, where a is the TG image and b is the DSC image. Detailed Embodiments

[0029] The present invention provides a preparation method for a nano-composite material with a 3DOM encapsulation structure, which comprises the following steps:

[0030] 1) The colloidal crystal template is impregnated in a metal ion precursor solution and then sequentially dried and calcined to obtain a 3DOM CoFe₂O₄ material;

[0031] 2) The 3DOM CoFe₂O₄ material is impregnated in an ammonium perchlorate solution and then freeze-dried to obtain a nanocomposite material with a 3DOM encapsulation structure;

[0032] The colloidal crystal template in step 1) is a polymethyl methacrylate colloidal crystal template or a polystyrene colloidal crystal template; the metal ion precursor solution contains iron nitrate, cobalt nitrate, citric acid and a solvent.

[0033] In the present invention, the polymethyl methacrylate (PMMA) colloidal crystal template or polystyrene (PS) colloidal crystal template in step 1) is preferably obtained by drying polymethyl methacrylate emulsion microspheres or polystyrene emulsion microspheres; the particle size of the polymethyl methacrylate emulsion microspheres or polystyrene emulsion microspheres is independently preferably 150 - 400 nm, further preferably 200 nm, 220 nm, 230 nm, 250 nm, 280 nm, 300 nm, 350 mm or 380 nm; the drying temperature is preferably 40 - 80 °C, further preferably 45 °C, 50 °C, 55 °C, 60 °C, 65 °C or 70 °C; the drying time is preferably 6 - 10 h, further preferably 6.5 h, 7 h, 7.5 h, 8 h, 8.5 h, 9 h or 9.5 h.

[0034] In the present invention, in the metal ion precursor solution of step 1), the metal ions are cobalt ions and iron ions, and the total concentration of the metal ions is preferably 0.8 - 2 mol / L, further preferably 0.9 - 1.8 mol / L, more preferably 1.2 - 1.6 mol / L; the molar ratio of cobalt ions to iron ions is preferably 1:0.5 - 2.5, further preferably 1:0.8 - 2.2, more preferably 1:1.5 - 2; the molar ratio of the metal ions to citric acid is preferably 1:0.5 - 2.0, further preferably 1:0.6 - 1.8, more preferably 1:0.8 - 1.2.

[0035] In the present invention, the solvent in step 1) preferably contains one or more of methanol, ethanol, ethylene glycol and glycerol.

[0036] In the present invention, the metal ion precursor solution is preferably obtained by stirring and mixing iron nitrate, cobalt nitrate, citric acid and a solvent, and the stirring and mixing time is preferably 3 - 5 h, further preferably 3.5 - 4.5 h, more preferably 4 h; the stirring and mixing speed is preferably 200 - 400 rpm, further preferably 220 rpm, 250 rpm, 300 rpm, 330 rpm or 360 rpm.

[0037] In the present invention, there is no limitation on the order of preparation of the metal ion precursor solution and the preparation of the colloidal crystal template.

[0038] In the present invention, the mass-volume ratio of the colloidal crystal template and the metal ion precursor solution in step 1) is preferably 1 g: 2.5 - 10 mL, more preferably 1 g: 3 - 9 mL, and still more preferably 1 g: 5 - 7 mL.

[0039] In the present invention, the impregnation time in step 1) is preferably 3 - 6 h, more preferably 3.5 - 5.5 h, and still more preferably 4 - 5 h; after impregnation, it is preferably filtered by suction to remove the excess filtrate on the colloidal crystal template to obtain a colloidal crystal template solid, and then dried and calcined in sequence; the vacuum degree of suction filtration is preferably 0.06 - 0.099 MPa, more preferably 0.08 - 0.097 MPa, and still more preferably 0.085 - 0.095 MPa.

[0040] In the present invention, the drying temperature in step 1) is preferably 30 - 70 °C, more preferably 35 °C, 40 °C, 45 °C, 50 °C, 55 °C, 60 °C or 65 °C; the drying time is preferably 8 - 10 h, more preferably 8.5 h, 9 h or 9.5 h.

[0041] In the present invention, the calcination temperature in step 1) is preferably 400 - 500 °C, more preferably 420 - 480 °C, and still more preferably 450 - 460 °C; the heat preservation time at the calcination temperature is preferably 4 - 6 h, more preferably 4.5 - 5.5 h, and still more preferably 5 h; the heating rate from the initial temperature to the calcination temperature is preferably 1 - 5 °C / min, more preferably 2 - 4 °C / min, and still more preferably 3 °C / min, and the initial temperature is preferably 20 - 25 °C, more preferably 21 - 24 °C, and still more preferably 22 - 23 °C; the calcination is preferably carried out in an air atmosphere.

[0042] In the present invention, the mass-volume ratio of the 3DOM CoFe2O4 material and the ammonium perchlorate solution in step 2) is preferably 1 g: 200 - 800 mL, more preferably 1 g: 250 - 750 mL, and still more preferably 1 g: 350 - 500 mL; the concentration of the ammonium perchlorate (AP) solution is preferably 0.01 - 0.16 g / mL, more preferably 0.02 - 0.14 g / mL, and still more preferably 0.03 - 0.12 g / mL.

[0043] In the present invention, the impregnation time in step 2) is preferably 0.5 - 6 min, more preferably 1 - 5 min, and still more preferably 2 - 3 min; the number of impregnation times is preferably 1 - 4 times, more preferably 2 - 3 times. After each impregnation, suction filtration is preferably carried out to remove the excess solution, and a solid composite material is obtained. The solid composite material is then freeze-dried; the vacuum degree of suction filtration is preferably 0.08 - 0.098 MPa, more preferably 0.085 - 0.095 MPa, and still more preferably 0.09 MPa; the suction filtration time is preferably 2 - 5 min, more preferably 3 - 4 min.

[0044] In the present invention, the temperature of freeze-drying in step 2) is preferably -50 to -10 °C, more preferably -45 °C, -40 °C, -35 °C, -30 °C or -20 °C; the freeze-drying time is preferably 8 - 32 h, more preferably 12 h, 15 h, 18 h, 24 h or 30 h; the pressure of freeze-drying is preferably 0.1 - 13 Pa, more preferably 0.2 - 5 Pa, and still more preferably 0.5 - 1 Pa.

[0045] In the present invention, the impregnation, suction filtration and freeze-drying of the 3DOM CoFe₂O₄ material in the ammonium perchlorate solution are taken as one cycle, and the number of cycles is preferably 1 - 4 times, more preferably 2 - 3 times.

[0046] The present invention also provides a nano-composite material with a 3DOM encapsulation structure prepared by the preparation method described above.

[0047] The nano-composite material with a 3DOM encapsulation structure of the present invention is widely used in the fields of solid propellants, aerospace and industrial catalysis, etc.

[0048] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0049] Example 1

[0050] PMMA emulsion microspheres with a particle size of 300 nm are placed in a blast drying oven at 55 °C and dried for 7 h to obtain a PMMA colloidal crystal template. 0.0133 mol of iron nitrate, 0.0067 mol of cobalt nitrate, 0.02 mol of citric acid, 12 mL of ethylene glycol and 8 mL of methanol are stirred and mixed at a speed of 250 rpm for 4 h to obtain a metal ion precursor solution.

[0051] 2.16 g of PMMA colloidal crystal template was impregnated in 20 mL of metal ion precursor solution for 4 h. After impregnation, the PMMA colloidal crystal template was filtered under vacuum of 0.095 MPa using a Buchner funnel and a vacuum pump to remove the excess filtrate. The obtained solid was dried in a forced-air drying oven at 60 °C for 8 h, and then the dried solid was placed in a tube furnace. In an air atmosphere, starting from an initial temperature of 23 °C, the temperature was raised to 450 °C at a heating rate of 1 °C / min and held at 450 °C for 5 h to obtain 3DOM CoFe2O4 material.

[0052] At room temperature, solid powder of AP was added to 100 mL of water and stirred to obtain an AP aqueous solution with a concentration of 0.115 g / mL. 0.05 g of 3DOM CoFe2O4 material was impregnated in 30 mL of the AP aqueous solution for 4 min. After impregnation, the solid composite material was filtered under vacuum of 0.088 MPa for 4 min using a micro-sample graduated cylinder type filtration device to remove the excess solution. The obtained solid composite material was freeze-dried at -30 °C and 1 Pa for 15 h to obtain the nanocomposite material 3DOM CoFe2O4@AP with a 3DOM encapsulation structure.

[0053] The image of the PMMA colloidal crystal template prepared in this example is as Figure 1 shown. As Figure 1 can be seen, PMMA microspheres self-assembled to form a hexagonal close-packed crystal template with regular shape, good monodispersity and uniformity; the diameter of PMMA microspheres is 0.2 - 0.24 μm.

[0054] The SEM image and TEM image of the 3DOM CoFe2O4 material prepared in this example are as Figure 2 shown, where a is the SEM image and b is the TEM image. As Figure 2 can be seen, the 3DOM CoFe2O4 material has a typical 3DOM structure with a continuous skeleton and regular macropores (calculated size is 189.8 nm).

[0055] The SEM images of 3DOM CoFe2O4@AP with different AP contents are as Figure 3 shown, where a is the AP mass fraction of 20 - 40%, b is the AP mass fraction of 60 - 80%, and c is the AP mass fraction ≥ 90%. As Figure 3 can be seen, with the increase of AP content, the macropores in the structure of the nanocomposite gradually shrink until they disappear, which means the transformation of AP from two-dimensional nanosheets to microsphere structure, and finally the growth size of AP is consistent with the size of the macropores of 3DOM CoFe2O4, thus proving the encapsulation effect of 3DOM CoFe2O4.

[0056] The SEM image and EDS image of the 3DOM CoFe2O4@AP prepared in this example are as Figure 4 shown. The EDS spectrum shows that Cl elements are evenly dispersed in the pores of 3DOM CoFe2O4, indicating that AP has grown successfully inside 3DOM CoFe2O4 and the size of AP is limited within 200 nm.

[0057] The TG graph and DSC graph of the 3DOM CoFe2O4@AP prepared in this example are as Figure 5 shown, where a is the TG graph and b is the DSC graph. From Figure 5 this, the specific content of AP in the composite material can be obtained. Meanwhile, in the DSC curve, the high-temperature decomposition peak of AP can be detected to be greatly advanced, which also proves that the composite material has good decomposition efficiency.

[0058] Example 2

[0059] PMMA emulsion microspheres with a particle size of 280 nm were placed in a forced-air drying oven at 65 °C for 8 h to obtain a PMMA colloidal crystal template. 0.016 mol of iron nitrate, 0.008 mol of cobalt nitrate, 0.02 mol of citric acid, 10 mL of ethylene glycol, and 10 mL of methanol were stirred and mixed at a rotation speed of 280 rpm for 4 h to obtain a metal ion precursor solution.

[0060] 2 g of the PMMA colloidal crystal template was impregnated in 18 mL of the metal ion precursor solution for 4.5 h. After impregnation, the PMMA colloidal crystal template was filtered using a Buchner funnel and a vacuum pump under a vacuum of 0.09 MPa to remove the excess filtrate. The obtained solid was placed in a forced-air drying oven at 65 °C for 8.5 h, and then the dried solid was placed in a tubular furnace. In an air atmosphere, starting from an initial temperature of 22 °C, the temperature was raised to 430 °C at a heating rate of 2 °C / min and held at 430 °C for 5.5 h to obtain a 3DOM CoFe2O4 material.

[0061] At room temperature, the solid powder of AP was added to 100 mL of water and stirred to obtain an AP aqueous solution with a concentration of 0.115 g / mL. 0.05 g of the 3DOM CoFe2O4 material was impregnated in 25 mL of the AP aqueous solution for 3 min. After impregnation, the solid composite material was filtered using a micro-sample measuring cylinder type filtering device under a vacuum of 0.09 MPa for 5 min to remove the excess solution. The obtained solid composite material was freeze-dried at -40 °C and 1 Pa for 18 h, and the above process of impregnation, filtration, and freeze-drying in the AP aqueous solution was repeated once to obtain a nanocomposite material 3DOM CoFe2O4@AP with a 3DOM encapsulation structure.

[0062] Example 3

[0063] The PMMA emulsion microspheres with a particle size of 350 nm were placed in a forced-air drying oven at 45 °C and dried for 7 h to obtain a PMMA colloidal crystal template. 0.02 mol of iron nitrate, 0.01 mol of cobalt nitrate, 0.03 mol of citric acid, 10 mL of ethanol and 6 mL of glycerol were stirred and mixed at a speed of 320 rpm for 3.5 h to obtain a metal ion precursor solution.

[0064] 2 g of the PMMA colloidal crystal template was immersed in 10 mL of the metal ion precursor solution for 5 h. After the immersion, the PMMA colloidal crystal template was filtered with a Buchner funnel and a vacuum pump under a vacuum degree of 0.078 MPa to remove the excess filtrate. The obtained solid was placed in a forced-air drying oven at 50 °C and dried for 9 h. Then, the dried solid was placed in a tube furnace. In an air atmosphere, starting from an initial temperature of 21 °C, the temperature was raised to 450 °C at a heating rate of 3 °C / min and held at 450 °C for 5 h to obtain the 3DOM CoFe2O4 material.

[0065] At room temperature, the solid powder of AP was added to 100 mL of water and stirred to obtain an AP aqueous solution with a concentration of 0.1 g / mL. 0.05 g of the 3DOM CoFe2O4 material was immersed in 20 mL of the AP aqueous solution for 5 min. After the immersion, the solid composite material was filtered with a micro-sample graduated cylinder type filtration device under a vacuum degree of 0.085 MPa for 3 min to remove the excess solution. The obtained solid composite material was freeze-dried at -30 °C and 5 Pa for 24 h. The above process of immersion, filtration and freeze-drying in the AP aqueous solution was repeated twice to obtain the nano-composite material 3DOM CoFe2O4@AP with a 3DOM encapsulation structure.

[0066] Example 4

[0067] The PS emulsion microspheres with a particle size of 220 nm were placed in a forced-air drying oven at 70 °C and dried for 8.5 h to obtain a PS colloidal crystal template. 0.018 mol of iron nitrate, 0.009 mol of cobalt nitrate, 0.03 mol of citric acid and 24 mL of ethylene glycol were stirred and mixed at a speed of 230 rpm for 4.5 h to obtain a metal ion precursor solution.

[0068] 2.16 g of the PS colloidal crystal template was immersed in 14 mL of the metal ion precursor solution for 3.5 h. After the immersion, the PS colloidal crystal template was filtered with a Buchner funnel and a vacuum pump under a vacuum degree of 0.09 MPa to remove the excess filtrate. The obtained solid was placed in a forced-air drying oven at 70 °C and dried for 8.5 h. Then, the dried solid was placed in a tube furnace. In an air atmosphere, starting from an initial temperature of 23 °C, the temperature was raised to 480 °C at a heating rate of 2.5 °C / min and held at 480 °C for 4.5 h to obtain the 3DOM CoFe2O4 material.

[0069] At room temperature, the solid powder of AP was added to 100 mL of water and stirred to obtain an AP aqueous solution with a concentration of 0.0557 g / mL. 0.05 g of 3DOM CoFe2O4 material was impregnated in 35 mL of the AP aqueous solution for 4 min. After the impregnation, a micro-sample graduated cylinder type suction filtration device was used to filter the solid composite material under a vacuum of 0.095 MPa for 2 min to remove the excess solution. The obtained solid composite material was freeze-dried at -35 °C and 3 Pa for 12 h to obtain the nanocomposite 3DOM CoFe2O4@AP with a 3DOM encapsulation structure.

[0070] The 3DOM CoFe2O4@AP with a 3DOM encapsulation structure prepared by the method of the present invention has good stability. Using the stable 3DOM CoFe2O4 skeleton as the template framework, macropores were constructed and the specific surface area of the composite material was greatly increased, which is beneficial to improving the mass transfer efficiency. The 3DOM CoFe2O4@AP with an encapsulation structure is widely used in fields such as solid propellants, aerospace, and industrial catalysis. The composite material of the present invention does not require the addition of expensive equipment, and in addition, the preparation process is simple and controllable.

[0071] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of a nanocomposite with a 3DOM encapsulation structure, characterized in that, It includes the following steps: 1) Immerse the colloidal crystal template in the metal ion precursor solution, and then successively perform drying and calcination to obtain the 3DOM CoFe2O4 material; 2) Immerse the 3DOM CoFe2O4 material in the ammonium perchlorate solution, and then perform freeze-drying to obtain the nanocomposite material with a 3DOM encapsulation structure; In step 1), the colloidal crystal template is a polymethyl methacrylate colloidal crystal template; the metal ion precursor solution contains iron nitrate, cobalt nitrate, citric acid and a solvent; the metal ions are cobalt ions and iron ions, and the molar ratio of the metal ions to citric acid is 1:0.5 - 2.0; In step 1), the calcination temperature is 400 - 450 °C, the heat preservation time at the calcination temperature is 4 - 6 h, and the heating rate to the calcination temperature is 1 - 5 °C / min.

2. The preparation method according to claim 1, wherein In step 1), the polymethyl methacrylate colloidal crystal template is obtained by drying polymethyl methacrylate emulsion microspheres; the particle size of the polymethyl methacrylate emulsion microspheres is 150 - 400 nm; the drying temperature is 40 - 80 °C, and the drying time is 6 - 10 h.

3. The preparation method according to claim 1 or 2, characterized in that, In the metal ion precursor solution of step 1), the total concentration of the metal ions is 0.8 - 2 mol / L, and the molar ratio of cobalt ions to iron ions is 1:0.5 - 2.

5.

4. The preparation method according to claim 3, wherein, In step 1), the solvent includes one or more of methanol, ethanol, ethylene glycol and glycerol.

5. The preparation method according to claim 3, characterized in that, In step 1), the mass-volume ratio of the colloidal crystal template to the metal ion precursor solution is 1 g:2.5 - 10 mL.

6. The preparation method according to claim 5, characterized in that, In step 1), the immersion time is 3 - 6 h; the drying temperature is 30 - 70 °C, and the drying time is 8 - 10 h.

7. The preparation method according to claim 6, characterized in that, In step 2), the mass-volume ratio of the 3DOM CoFe2O4 material to the ammonium perchlorate solution is 1 g:200 - 800 mL; the concentration of the ammonium perchlorate solution is 0.01 - 0.16 g / mL.

8. The preparation method according to claim 7, characterized in that, In step 2), the immersion time is 0.5 - 6 min; the freeze-drying temperature is -50 - -5 °C, and the freeze-drying time is 8 - 32 h.

9. The nanocomposite material with a 3DOM encapsulation structure prepared by the preparation method according to any one of claims 1 - 8.

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