A one-dimensional Ni-doped magnetic carbon nanocomposite material derived from HOF and its preparation method

Abstract

This invention discloses a one-dimensional Ni-doped magnetic carbon-based nanocomposite material derived from HOF and its preparation method, belonging to the field of electromagnetic wave absorbing materials. The material exhibits good thermal stability and a large specific surface area, meeting the requirements for wide bandwidth and lightweight absorbing materials. This invention utilizes a solvothermal method and high-temperature thermal reduction under an inert atmosphere to prepare an electromagnetic wave absorbing material with multiple loss characteristics. The doping of Ni nanoparticles effectively enhances the magnetic loss capability of the material and also improves the overall wave impedance matching characteristics. The formation of Ni-based coordination compounds also results in the generation of a multi-level nanotube structure, providing favorable conditions for multiple scattering of electromagnetic waves and exhibiting excellent electromagnetic wave absorption performance. With a thickness of 2.95 mm, its minimum reflectivity reaches -50.4 dB, and its effective absorption bandwidth reaches 7.32 GHz, while the mass percentage of the absorbing agent in the coating is only 10 wt.%.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic wave absorbing materials technology, and particularly relates to a one-dimensional Ni-doped magnetic carbon-based nanocomposite absorbing material derived from HOF and its preparation method. Background Technology

[0002] The rapid development of modern electromagnetic communication technologies, such as the successive research and application of 4G and 5G equipment, and the widespread use of various electronic products in daily life, have placed people in a complex electromagnetic pollution environment at all times, seriously affecting their health. At the same time, the use of various precision electronic devices also requires effective solutions to electromagnetic compatibility (EMC) problems caused by this complex electromagnetic environment. Currently, the application of electromagnetic wave absorbing and shielding materials has become the main means to effectively solve various electromagnetic pollution and EMC problems. Meanwhile, designing lightweight, strong-absorbing, wide-bandwidth, and thin-film absorbing materials has become a key challenge for researchers.

[0003] The design of carbon-based microwave absorbing materials is an effective method for preparing lightweight microwave absorbing agents, with macroscopic porous structures and microscopic low-dimensional designs being the main means of achieving this. For example, the use of low-dimensional carbon materials such as graphene and carbon nanotubes, as well as the design of honeycomb structure microwave absorbing materials, can effectively achieve the application goal of lightweight microwave absorbing materials. However, the application of single carbon microwave absorbing materials often leads to drawbacks such as large coating thickness and narrow effective absorption bandwidth. To overcome the shortcomings of using single carbon materials, uniformly loading magnetic microwave absorbing materials onto a carbon material framework has become an effective method. The research group of Professor Chen Ping at Dalian University of Technology has developed a high-performance magnetic graphene aerogel nanocomposite material with low density and enhanced microwave absorption performance through a two-step strategy combining hydrothermal reaction and in-situ pyrolysis (Synthesis of magnetic graphene aerogels for microwave absorption by a in-situ pyrolysis, Carbon, 2019-05-01). Meanwhile, the research group of Professor Yao Zhengjun at Nanjing University of Aeronautics and Astronautics, in collaboration with Nanyang Technological University, loaded co-doped Ni-Zn ferrite onto the surface of graphene using a one-pot hydrothermal method, resulting in both sides of the graphene sheet being densely covered with ferrite nanoparticles. Electromagnetic properties show that the graphene content plays a crucial role in determining the dielectric properties and magnetic anisotropy of carbon materials, which further affects the impedance matching and attenuation capability of the absorber (Small magnetic Co-doped NiZn ferrite / graphene nanocomposites and their dual-region microwave absorption performance, Journal of Materials Chemistry C, 2016-09-23). Although these methods have effectively improved the magnetic loss capability of materials, ensuring the uniform dispersion of magnetic nanoparticles in the carbon framework remains a difficult problem to solve effectively.

[0004] Hydrogen-bonded organic frameworks (HOFs) are special porous crystalline materials with high porosity and high specific surface area, mainly formed through the self-assembly of intermolecular hydrogen bonds between organic building blocks. Their advantages, such as mild synthesis conditions, high crystallinity, and large specific surface area, make them promising for broad applications. However, the relatively weak hydrogen bond strength of HOFs results in poor structural stability, inevitably leading to structural collapse under high-temperature conditions. Commonly used and effective methods to improve the structural stability of HOFs include π-π stacking, H-bond interpenetration, electrostatic attraction, and post-synthesis modification. While these methods can effectively improve the structural stability of HOFs, their relatively singular electromagnetic wave attenuation capability severely hinders the improvement of electromagnetic wave absorption performance. Therefore, introducing magnetic materials to enhance electromagnetic wave absorption performance while ensuring the structural stability of HOF materials has become an urgent problem to be solved. Summary of the Invention

[0005] This invention provides a one-dimensional Ni-doped magnetic carbon-based nanocomposite microwave absorbing material derived from HOF and its preparation method. The microwave absorbing material still exhibits strong absorption of electromagnetic waves and wide bandwidth characteristics even at low filling degree, demonstrating excellent electromagnetic wave absorption performance. The preparation method is low in cost and simple in process, and can be used for large-scale industrial production.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A one-dimensional Ni-doped magnetic carbon-based nanocomposite electromagnetic absorbing material derived from HOF is disclosed. The electromagnetic absorbing agent has a structure of a one-dimensional hollow tubular nanostructure and uniformly distributed Ni nanoparticles. The one-dimensional hollow tubular structure is multi-interface, with metallic Ni uniformly distributed throughout the carbon framework. This is beneficial for improving the material's multiple loss capability, increasing the multiple scattering of electromagnetic waves within the material, and optimizing the material's impedance matching.

[0008] The hollow tubular structure has a diameter of no more than 100 nm, and Ni nanoparticles are uniformly distributed throughout the carbon skeleton.

[0009] The preparation method of the above-mentioned HOF-derived one-dimensional Ni-doped magnetic carbon-based nanocomposite microwave absorbing material includes the following steps:

[0010] Step 1: Dissolve 1.2 mmol (0.1513 g) of melamine in 35 mL of methanol solution and stir magnetically for 10 min. Then, dissolve 1.2 mmol (0.2522 g) of trimesic acid in the above solution and stir for 30 min. After that, dissolve 1.2 mmol (0.3489 g) of nickel nitrate hexahydrate (Ni(NO3)2·6H2O) in the above solution and continue to stir magnetically for 10 min.

[0011] The molar ratio of melamine, pyromellitic acid, and nickel nitrate hexahydrate is 1:1:1.

[0012] The stirring was carried out at room temperature (20-30℃);

[0013] Step 2: Transfer the above mixed solution to a 50ml reactor for a solvothermal reaction at 150℃ for 12 hours. After the reactor cools naturally to room temperature, the solvothermal product is centrifuged, washed, and dried to obtain Ni. 2+ Doped HOF precursors;

[0014] The mixed solution accounts for 70% of the volume in the reactor.

[0015] The solution used for centrifugation and washing of the solvothermal products was methanol.

[0016] Step 3: Ni 2+ The doped HOF precursor was calcined in a nitrogen atmosphere with a heating rate of 2℃ / min, a heat treatment temperature of 600-900℃, and a holding time of 2h, finally yielding a one-dimensional Ni-doped magnetic carbon-based nanocomposite microwave absorbing material.

[0017] Beneficial effects: This invention provides a one-dimensional Ni-doped magnetic carbon-based nanocomposite microwave absorbing material derived from HOF and its preparation method. It utilizes melamine and trimesic acid to form a hydrogen-bonded organic framework at room temperature, resulting in a one-dimensional nanorod structure. The method incorporates Ni... 2+ Under solvothermal reaction conditions, it undergoes a coordination reaction with melamine and trimesic acid, partially disrupting the original hydrogen-bonded functional groups and resulting in a hollow tubular structure. Simultaneously, the formation of coordination bonds significantly enhances the structural stability of the original HOF material. The doping of Ni nanoparticles effectively improves the material's magnetic loss capability and also improves the overall wave impedance matching characteristics. Furthermore, the formation of Ni-based coordination compounds provides favorable conditions for achieving multiple scattering of electromagnetic waves. Compared to traditional microwave absorbers, the microwave absorbing material prepared by this invention features a wide effective absorption bandwidth at extremely low filling density, strong absorption capability, and light weight, exhibiting excellent electromagnetic wave absorption performance. Moreover, the preparation method of this invention does not require complex synthesis equipment, is simple in process, low in cost, and suitable for large-scale industrial production. Attached Figure Description

[0018] Figure 1 SEM images of the HOF precursor products prepared by liquid-phase stirring at room temperature in Examples 1, 2, 3, and 4 of this invention;

[0019] Figure 2 The Ni obtained in Examples 1, 2, 3, and 4 of this invention 2+SEM image of the doped HOF precursor;

[0020] Figure 3 This is a SEM image of Ni@CNT-600 obtained in Example 1 of the present invention;

[0021] Figure 4 This is a SEM image of Ni@CNT-700 obtained in Example 2 of the present invention;

[0022] Figure 5 This is a SEM image of Ni@CNT-800 obtained in Example 3 of the present invention;

[0023] Figure 6 This is a SEM image of Ni@CNT-900 obtained in Example 4 of the present invention;

[0024] Figure 7 The Ni obtained in Examples 1, 2, 3, and 4 of this invention 2+ FTIR spectra of doped HOF precursors;

[0025] Figure 8 The Ni obtained in Examples 1, 2, 3, and 4 of this invention 2+ TGA image of the doped HOF precursor;

[0026] Figure 9 The images show the XRD patterns of Ni@CNT-600, Ni@CNT-700, Ni@CNT-800, and Ni@CNT-900 obtained in Examples 1, 2, 3, and 4 of this invention.

[0027] Figure 10 The electrical loss factor diagrams are for Ni@CNT-600, Ni@CNT-700, Ni@CNT-800, and Ni@CNT-900 obtained in Examples 1, 2, 3, and 4 of this invention.

[0028] Figure 11 The magnetic loss factor diagrams of Ni@CNT-600, Ni@CNT-700, Ni@CNT-800, and Ni@CNT-900 obtained in Examples 1, 2, 3, and 4 of this invention are shown.

[0029] Figure 12 The image shows the reflection loss of Ni@CNT-600 obtained in Example 1 of this invention.

[0030] Figure 13 The reflection loss diagram of Ni@CNT-700 obtained in Example 2 of this invention;

[0031] Figure 14 The image shows the reflection loss of Ni@CNT-800 obtained in Example 3 of this invention.

[0032] Figure 15 The image shows the reflection loss of Ni@CNT-900 obtained in Example 4 of this invention.

[0033] Figure 16 This is a schematic diagram illustrating the principle of the preparation method of the present invention. Detailed Implementation

[0034] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments:

[0035] Example 1

[0036] A method for preparing a one-dimensional Ni-doped magnetic carbon-based nanocomposite microwave absorbing material derived from HOF includes the following steps:

[0037] Step 1: Dissolve 1.2 mmol (0.1513 g) of melamine in 35 mL of methanol solution and stir magnetically for 10 min. Then, dissolve 1.2 mmol (0.2522 g) of trimesic acid in the above solution and stir for 30 min. Afterward, dissolve 1.2 mmol (0.3489 g) of nickel nitrate hexahydrate (Ni(NO3)2·6H2O) in the above solution and continue stirring magnetically for 10 min.

[0038] Step 2: The above mixed solution was transferred to a 50ml reaction vessel for a solvothermal reaction at 150℃ for 12 hours. After the reaction vessel cooled naturally to room temperature, the solvothermal product was subjected to centrifugation, methanol washing, and drying to obtain Ni. 2+ Doped HOF precursors;

[0039] Step 3, Ni 2+ The doped HOF precursor was calcined under a nitrogen atmosphere with a heating rate of 2℃ / min, a heat treatment temperature of 600℃, and a holding time of 2h, finally yielding a one-dimensional Ni-doped magnetic carbon-based nanocomposite material Ni@CNT-600.

[0040] Example 2

[0041] A method for preparing a one-dimensional Ni-doped magnetic carbon-based nanocomposite microwave absorbing material derived from HOF includes the following steps:

[0042] Step 1: Dissolve 1.2 mmol (0.1513 g) of melamine in 35 mL of methanol solution and stir magnetically for 10 min. Then, dissolve 1.2 mmol (0.2522 g) of trimesic acid in the above solution and stir for 30 min. Afterward, dissolve 1.2 mmol (0.3489 g) of nickel nitrate hexahydrate (Ni(NO3)2·6H2O) in the above solution and continue stirring magnetically for 10 min.

[0043] Step 2: The above mixed solution was transferred to a 50ml reaction vessel for a solvothermal reaction at 150℃ for 12 hours. After the reaction vessel cooled naturally to room temperature, the solvothermal product was subjected to centrifugation, methanol washing, and drying to obtain Ni. 2+ Doped HOF precursors;

[0044] Step 3, Ni 2+ The doped HOF precursor was calcined under a nitrogen atmosphere with a heating rate of 2℃ / min, a heat treatment temperature of 700℃, and a holding time of 2h, finally yielding a one-dimensional Ni-doped magnetic carbon-based nanocomposite material Ni@CNT-700.

[0045] Example 3

[0046] A method for preparing a one-dimensional Ni-doped magnetic carbon-based nanocomposite microwave absorbing material derived from HOF includes the following steps:

[0047] Step 1: Dissolve 1.2 mmol (0.1513 g) of melamine in 35 mL of methanol solution and stir magnetically for 10 min. Then, dissolve 1.2 mmol (0.2522 g) of trimesic acid in the above solution and stir for 30 min. Afterward, dissolve 1.2 mmol (0.3489 g) of nickel nitrate hexahydrate (Ni(NO3)2·6H2O) in the above solution and continue stirring magnetically for 10 min.

[0048] Step 2: The above mixed solution was transferred to a 50ml reaction vessel for a solvothermal reaction at 150℃ for 12 hours. After the reaction vessel cooled naturally to room temperature, the solvothermal product was subjected to centrifugation, methanol washing, and drying to obtain Ni. 2+ Doped HOF precursors;

[0049] Step 3, Ni 2+ The doped HOF precursor was calcined under a nitrogen atmosphere with a heating rate of 2℃ / min, a heat treatment temperature of 800℃, and a holding time of 2h, finally yielding a one-dimensional Ni-doped magnetic carbon-based nanocomposite material Ni@CNT-800.

[0050] Example 4

[0051] A method for preparing a one-dimensional Ni-doped magnetic carbon-based nanocomposite microwave absorbing material derived from HOF includes the following steps:

[0052] Step 1: Dissolve 1.2 mmol (0.1513 g) of melamine in 35 mL of methanol solution and stir magnetically for 10 min. Then, dissolve 1.2 mmol (0.2522 g) of trimesic acid in the above solution and stir for 30 min. Afterward, dissolve 1.2 mmol (0.3489 g) of nickel nitrate hexahydrate (Ni(NO3)2·6H2O) in the above solution and continue stirring magnetically for 10 min.

[0053] Step 2: The above mixed solution was transferred to a 50ml reaction vessel for a solvothermal reaction at 150℃ for 12 hours. After the reaction vessel cooled naturally to room temperature, the solvothermal product was subjected to centrifugation, methanol washing, and drying to obtain Ni. 2+ Doped HOF precursors;

[0054] Step 3, Ni 2+ The doped HOF precursor was calcined under a nitrogen atmosphere with a heating rate of 2℃ / min, a heat treatment temperature of 900℃, and a holding time of 2h, finally yielding a one-dimensional Ni-doped magnetic carbon-based nanocomposite material Ni@CNT-900.

[0055] Figure 1 These are SEM images of the HOF precursor products prepared by liquid-phase stirring at room temperature in Examples 1, 2, 3, and 4 of this invention. Figure 1 It can be seen that the HOF precursor products prepared by liquid-phase stirring exhibit a one-dimensional nanorod structure with a diameter of less than 100 nm.

[0056] Figure 2 The Ni obtained in Examples 1, 2, 3, and 4 of this invention 2+ SEM images of the doped HOF precursor. Figure 2 It can be seen that Ni 2+ The doped HOF precursors exhibit a non-uniform one-dimensional hollow nanotube structure, with diameters mostly less than 100 nm.

[0057] Figure 3 This is a SEM image of Ni@CNT-600 obtained in Example 1 of the present invention. From... Figure 3 It can be seen that Ni@CNT-600 still perfectly retains its original hollow nanotube structure after being calcined at 600℃.

[0058] Figure 4 This is a SEM image of Ni@CNT-700 obtained in Example 2 of the present invention. From... Figure 4 It can be seen that Ni@CNT-700 still perfectly retains its original hollow nanotube structure after being calcined at 700℃.

[0059] Figure 5This is a SEM image of Ni@CNT-800 obtained in Example 3 of the present invention. From... Figure 5 It can be seen that Ni@CNT-800 retains its original hollow nanotube structure quite perfectly after being calcined at 800℃.

[0060] Figure 6 This is a SEM image of Ni@CNT-900 obtained in Example 4 of the present invention. From... Figure 6 It can be seen that Ni@CNT-900 retains its original hollow nanotube structure quite well after calcination at 900℃.

[0061] Figure 7 The Ni obtained in Examples 1, 2, 3, and 4 of this invention 2+ FTIR spectra of the doped HOF precursor. From Figure 7 It can be seen that in the hydrogen bond region (4000-2500 cm⁻¹) -1 Approximately 3391, 3224, and 3109 cm -1 The absorption peaks at [value] correspond to the stretching vibrations of the NH bond in the secondary amide, the OH bond in the hydroxyl group, and the CH bond in the aromatic ring, respectively. Notably, the broadening of the absorption peaks for the NH and OH bonds indicates that these molecules have formed a correlated state due to the presence of hydrogen bonds. Furthermore, the absorption peak at approximately 1699 cm⁻¹... -1 The absorption peak at approximately 1651 cm⁻¹ corresponds to the stretching vibration of the C=O bond in secondary amides (amide I peak). -1 The absorption peak at approximately 1326 cm⁻¹ corresponds to the bending vibration of the NH bond in secondary amides (amide II peak). -1 The absorption peak at the point corresponds to the stretching vibration of the CN bond of the secondary amide (amide III peak); this indicates that melamine and trimesic acid undergo an amidation reaction, and the resulting covalent bond modification is conducive to the generation of chemical cross-linking, thereby improving the structural stability of the HOF material.

[0062] Figure 8 The Ni obtained in Examples 1, 2, 3, and 4 of this invention 2+ TGA image of the doped HOF precursor. From Figure 8 It can be seen that the weight loss from room temperature to 250 °C (17%) is attributed to the removal of hydrogen-bonded water molecules; the weight loss from 250 °C to 750 °C (67.9%) is attributed to the removal of oxygen-containing functional groups and the pyrolysis and graphitization of the carbon framework; above 750 °C, Ni... 2+ The weight of the doped HOF precursor product is no longer lost, and the pyrolysis process is complete.

[0063] Figure 9The images show the XRD patterns of Ni@CNT-600, Ni@CNT-700, Ni@CNT-800, and Ni@CNT-900 obtained in Examples 1, 2, 3, and 4 of this invention. Figure 9 It can be seen that as the temperature increases, the (1 0 0) crystal plane diffraction peak of graphitized carbon gradually becomes sharper from broad and gentle, indicating that the degree of graphitization of the sample gradually increases. Secondly, the 2θ diffraction peaks at approximately 44.5°, 51.8°, and 76.4° correspond to the (1 1 1), (2 0 0), and (2 2 0) crystal planes of cubic Ni; the XRD diffraction peaks of ferromagnetic Ni indicate that when the heat treatment temperature is above 600℃, Ni... 2+ It can be completely reduced to its metallic elemental state.

[0064] Figure 10 This is a graph showing the electrical loss factor of Ni@CNT-600, Ni@CNT-700, Ni@CNT-800, and Ni@CNT-900 obtained in Examples 1, 2, 3, and 4 of this invention. From... Figure 10 It can be seen that Ni@CNT-600 has the weakest electrical loss capability, while Ni@CNT-900 has the largest electrical loss factor and the strongest electrical loss capability. This is mainly due to the change in the degree of graphitization of the material during the high-temperature carbonization process. The electrical loss capability of Ni@CNT-700 is slightly higher than that of Ni@CNT-800. This is because the product calcined at 800℃ undergoes a certain degree of structural breakage, which reduces the material's electrical loss capability.

[0065] Figure 11 This is a magnetic loss factor diagram for Ni@CNT-600, Ni@CNT-700, Ni@CNT-800, and Ni@CNT-900 obtained in Examples 1, 2, 3, and 4 of this invention. From... Figure 11 It can be seen that Ni@CNT-600, Ni@CNT-700 and Ni@CNT-800 have similar magnetic loss capabilities, indicating that the heat treatment temperature has little effect on the change of the magnetic properties of the material; while the magnetic loss capability of Ni@CNT-900 is reduced, mainly because the one-dimensional nanotube structure partially collapsed during this heat treatment process, resulting in a reduction in the magnetic loss capability of the material.

[0066] The microwave absorption material of this invention has a filling amount of 10 wt.% in a paraffin substrate. The microwave absorption capacity was tested, and the results are as follows:

[0067] Figure 12 This is a reflection loss diagram of Ni@CNT-600 obtained in Example 1 of the present invention. From... Figure 12 It can be seen that Ni@CNT-600 has virtually no effective microwave absorption performance in the 8-18GHz range.

[0068] Figure 13 This is a reflection loss diagram of Ni@CNT-700 obtained in Example 2 of the present invention. From... Figure 13 As can be seen, Ni@CNT-700 exhibits excellent electromagnetic wave absorption performance in the Ku band. With a thickness of 2.95mm, its minimum reflectivity can reach -54dB, and its effective absorption bandwidth can reach 7.32GHz (10.64-17.96GHz).

[0069] Figure 14 This is a reflection loss diagram of Ni@CNT-800 obtained in Example 3 of the present invention. From... Figure 14 As can be seen, Ni@CNT-800 also exhibits good electromagnetic wave absorption performance in the Ku band. With a thickness of 2.4mm, its minimum reflectivity can reach -56.9dB, and its effective absorption bandwidth can reach 5.95GHz (12.05-18GHz).

[0070] Figure 15 This is a reflection loss diagram of Ni@CNT-900 obtained in Example 4 of the present invention. From... Figure 15 It can be seen that Ni@CNT-900 exhibits poor absorption performance in the 8-18GHz range, and its absorption performance is far worse than that of Ni@CNT-700 and Ni@CNT-800.

[0071] The microwave absorption principle of the one-dimensional HOF-derived Ni-doped magnetic carbon nanotube composite absorbing material of this invention is as follows: First, by introducing Ni... 2+ The Ni-doped magnetic carbon nanotube composite material undergoes a coordination reaction with melamine and trimesic acid, resulting in a hollow tubular structure. This effectively increases the multiple scattering and absorption of electromagnetic waves within the material. Simultaneously, the uniform dispersion of Ni magnetic metal nanoparticles within the carbon framework effectively increases the material's magnetic loss capability and also effectively modulates its wave impedance matching characteristics. Therefore, the one-dimensional Ni-doped magnetic carbon-based nanotube composite material synthesized in this invention exhibits excellent electromagnetic wave absorption performance.

[0072] The above description is only a preferred embodiment of the present invention. For those skilled in the art, various corresponding changes and modifications can be made based on the above technical solutions and concepts, and all such changes and modifications should be included within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a one-dimensional Ni-doped magnetic carbon-based nanocomposite microwave absorbing material derived from HOF, characterized in that, Includes the following steps: Step 1: Dissolve melamine in methanol solution, stir until homogeneous, then dissolve trimesic acid in the solution while stirring to form a hydrogen-bonded organic framework; Step 2: Dissolve nickel nitrate hexahydrate in the solution from Step 1 and continue stirring; then carry out a solvothermal reaction at 150˚C, Ni 2+ Under solvothermal reaction conditions, Ni underwent a coordination reaction with melamine and trimesic acid, partially disrupting the original hydrogen-bonded functional groups and producing a hollow tubular structure. After the reaction was completed and naturally cooled to room temperature, the product was subjected to subsequent centrifugation, washing, and drying to obtain Ni. 2+ Doped HOF precursors; Step 3: Take the Ni obtained in Step 2 2+ The doped HOF precursor was calcined at 600-900˚C under a nitrogen atmosphere to obtain a one-dimensional Ni-doped magnetic carbon-based nanocomposite microwave absorbing material. The microwave absorbing material is composed of a one-dimensional nano-hollow tubular structure and uniformly distributed Ni nanoparticles. The one-dimensional nano-hollow tubular structure is multi-interface, and metallic Ni is uniformly distributed throughout the carbon skeleton.

2. The method for preparing the HOF-derived one-dimensional Ni-doped magnetic carbon-based nanocomposite microwave absorbing material according to claim 1, characterized in that, Step 1 is performed at room temperature.

3. The method for preparing the HOF-derived one-dimensional Ni-doped magnetic carbon-based nanocomposite microwave absorbing material according to claim 1 or 2, characterized in that, The molar ratio of melamine, trimesic acid, and nickel nitrate hexahydrate is 1:1:

1.

4. The method for preparing the HOF-derived one-dimensional Ni-doped magnetic carbon-based nanocomposite microwave absorbing material according to claim 1, characterized in that, The reaction time for the solvothermal reaction in step 2 is 12 h.

5. The method for preparing the HOF-derived one-dimensional Ni-doped magnetic carbon-based nanocomposite microwave absorbing material according to claim 1, characterized in that, In step 3, the heating rate for calcination is 2˚C / min, and the holding time is 2 h.

6. The HOF-derived one-dimensional Ni-doped magnetic carbon-based nanocomposite microwave absorbing material prepared by the method of claim 1, characterized in that, The structure of the microwave absorbing material consists of a one-dimensional nano-hollow tubular structure and uniformly distributed Ni nanoparticles; the one-dimensional nano-hollow tubular structure has multiple interfaces, and the Ni nanoparticles are uniformly distributed throughout the carbon skeleton.

7. The HOF-derived one-dimensional Ni-doped magnetic carbon-based nanocomposite microwave absorbing material according to claim 6, characterized in that, The diameter of the one-dimensional nano-hollow tubular structure is no greater than 100 nm.

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