Carbon-based composite wave-absorbing material and preparation method thereof

Abstract

The invention relates to a carbon-based composite wave-absorbing material and a preparation method thereof, in particular to a nickel-loaded flaky molybdenum carbide / carbon two-dimensional composite wave-absorbing material prepared by adopting a supramolecular self-assembly-hydrothermal-high-temperature carbonization method. According to the preparation method, nickel nanoparticles are loaded on molybdenum carbide / carbon nanosheets by adopting a hydrothermal-high-temperature carbonization method, the nickel-loaded flaky molybdenum carbide / carbon two-dimensional composite material with large specific surface area and uniform size is obtained, a plurality of loss mechanisms are brought to the nickel-loaded flaky molybdenum carbide / carbon two-dimensional composite material by a multiphase polycrystalline form, and electric conduction, dielectric and magnetic loss are mutually coordinated, so that the nickel-loaded flaky molybdenum carbide / carbon two-dimensional composite material has good impedance matching characteristics; and a relatively strong wave absorbing property can be obtained at a low load rate. The carbon-based composite wave-absorbing material provided by the invention is relatively simple in preparation method, low in cost and capable of effectively reducing the load rate and obtaining strong electromagnetic wave absorption performance.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method of a multiphase polymorphous carbon-based composite microwave absorption material with synergistic electric conduction-dielectric-magnetic loss, in particular to a method for preparing a nickel-loaded molybdenum carbide / carbon two-dimensional composite wave-absorbing material by using a supramolecular self-assembly-hydrothermal-high-temperature carbonization method. BACKGROUND

[0002] With the rapid development of society, the material civilization life is greatly improved, and modern information technology and electronic terminals bring us many conveniences while making the environment full of electromagnetic wave pollution. In order to solve the existing potential problems, it is urgent to develop a more efficient and stable wave-absorbing material with good impedance matching characteristics and electromagnetic loss characteristics, so as to maximize the conversion of electromagnetic wave energy into other forms of energy for dissipation and reduce the secondary pollution caused by reflection on the material surface.

[0003] In recent years, carbon-based materials, metal carbides and metal magnetic particles have attracted extensive research due to their electromagnetic wave attenuation ability. However, single carbon material or metal carbide cannot meet the requirements of high-performance wave-absorbing materials. In order to achieve stronger wave-absorbing performance and wider absorption frequency band, carbon materials, metal carbides and metal magnetic particles can be combined to make the electric conduction, dielectric and magnetic loss mechanisms synergistic, so as to optimize the impedance matching characteristics. The document "ACS Applied Materials & Interfaces 10 (2018) 24920-24929" discloses a kind of hollow nitrogen-doped carbon polyhedron prepared by using metal organic framework as a template, wherein CoNi alloy nanoparticles containing nitrogen-doped graphene are embedded to obtain CoNi@NG-NCPs. Due to the enhanced dielectric loss and better impedance matching characteristics, the best sample obtains a minimum reflection loss of-24.03 dB at a loading rate of 35%, and an effective absorption bandwidth of 4.32 GHz at 2.5 mm. However, the loading rate is high and the absorption performance is poor. Therefore, it is necessary to explore a kind of composite wave-absorbing material with lower loading rate and stronger absorption performance. SUMMARY

[0004] The application studies a nickel-loaded molybdenum carbide / carbon two-dimensional composite wave-absorbing material and a preparation method thereof. First, phosphomolybdic acid-polydopamine nanosheets are prepared by a supramolecular self-assembly method: in a Tris buffer solution as a reaction environment, under the action of an anionic surfactant, the phosphomolybdic acid-polydopamine nanosheets are synthesized. Then, nickel nanoparticles are loaded on the molybdenum carbide / carbon nanosheets by using a hydrothermal-high-temperature carbonization method, so as to synthesize the nickel-loaded molybdenum carbide / carbon two-dimensional composite wave-absorbing material with multiphase polymorphous. The electric conduction, dielectric and magnetic loss are synergistic, so that the impedance matching characteristics of the material are optimized, and the wave-absorbing performance of the composite material is improved.

[0005] The technical scheme of the application is as follows:

[0006] A carbon-based composite microwave absorbing material comprises nickel nanoparticles and molybdenum carbide / carbon nanosheets, wherein the nickel nanoparticles are uniformly loaded on the molybdenum carbide / carbon nanosheets to construct the carbon-based composite microwave absorbing material.

[0007] Furthermore, the carbon-based composite microwave absorbing material is a nickel-loaded sheet-like molybdenum carbide / carbon two-dimensional composite microwave absorbing material.

[0008] Furthermore, the carbon-based composite microwave absorbing material is a multiphase, polycrystalline, conductivity-dielectric-magnetic loss synergistic composite microwave absorbing material.

[0009] Furthermore, the carbon-based composite absorbing material absorbs electromagnetic waves.

[0010] A method for preparing carbon-based composite microwave absorbing materials, characterized by: preparing nickel-loaded sheet-like molybdenum carbide / carbon two-dimensional composite microwave absorbing materials using a supramolecular self-assembly-hydrothermal-high-temperature carbonization method; the specific steps are as follows:

[0011] S1 according to m 三羟甲基氨基甲烷 :m 盐酸 =1:(0.18, 0.25, 0.29), dissolve tris(hydroxymethyl)aminomethane and concentrated hydrochloric acid in deionized water, then according to m 磷钼酸 :m 十二烷基硫酸钠 :m 盐酸多巴胺 = 1:3:1, phosphomolybdic acid, sodium dodecyl sulfate and dopamine hydrochloride were dissolved in the above solution, stirred at room temperature for 10 h, and the product was collected by centrifugation and washing to obtain phosphomolybdic acid-polydopamine nanosheets;

[0012] S2 according to m 磷钼酸-聚多巴胺纳米片 :m 氯化镍 :m 氯化铵 :m 氨水 =2:2:1:3.6, dissolve the phosphomolybdic acid-polydopamine nanosheets obtained in S1, nickel chloride, ammonium chloride and ammonia in deionized water, stir for 30 min, transfer to 100 ml hydrothermal reactor and react at 120 °C for 6 h, collect the product by centrifugation and washing to obtain phosphomolybdic acid-polydopamine-nickel chloride nanosheets;

[0013] S3: The phosphomolybdic acid-polydopamine-nickel chloride nanosheets obtained in S2 were placed in a tube furnace under nitrogen protection and held at 700°C for 2 hours at a heating rate of 5°C / min. After cooling in the furnace, nickel-supported sheet molybdenum carbide / carbon two-dimensional composite material was obtained.

[0014] The present invention has the following beneficial effects:

[0015] 1. This invention provides a simple and safe method for preparing nickel-loaded sheet-like molybdenum carbide / carbon two-dimensional composite microwave absorbing material and its preparation method. First, phosphomolybdic acid-polydopamine nanosheets are prepared via supramolecular self-assembly: using Tris buffer solution as the reaction environment and anionic surfactants, phosphomolybdic acid-polydopamine nanosheets are synthesized. Then, a hydrothermal-high temperature carbonization method is used to load nickel nanoparticles onto the molybdenum carbide / carbon nanosheets, synthesizing a multiphase, polymorphic nickel-loaded sheet-like molybdenum carbide / carbon two-dimensional composite microwave absorbing material.

[0016] 2. The two-dimensional nanosheet structure composed of molybdenum carbide and carbon provides a larger specific surface area, allowing more electromagnetic waves to be absorbed at the material surface and dissipated as other forms of energy. The contact between adjacent nanosheets establishes an effective conductive network, enhancing the energy dissipation of electromagnetic waves. The uniformly loaded nickel magnetic particles on the molybdenum carbide / carbon nanosheets introduce magnetic losses into the conductivity-dielectric system, synergistically forming a nickel-loaded sheet-like two-dimensional composite microwave absorbing material with synergistic conductivity-dielectric-magnetic loss characteristics.

[0017] 3. The electromagnetic parameters of the nickel-loaded sheet-like molybdenum carbide / carbon two-dimensional composite absorbing material prepared in this invention were tested using the coaxial method. The results showed that it can obtain good impedance matching characteristics at a low loading rate, thus achieving good electromagnetic wave absorption performance. This demonstrates that the multiphase polycrystalline, conductivity-dielectric-magnetic loss synergistic composite absorbing material constructed using the supramolecular self-assembly-hydrothermal-high-temperature carbonization method can effectively reduce the loading rate and obtain good electromagnetic wave absorption performance. Attached Figure Description

[0018] Figure 1 These are XRD patterns of the nickel-supported sheet-like molybdenum carbide / carbon two-dimensional composite materials prepared in Examples 1, 2, and 3 of this invention;

[0019] Figure 2 This is a TEM image of the nickel-supported sheet-like molybdenum carbide / carbon two-dimensional composite material prepared in Example 1;

[0020] Figure 3 This is a waveform absorption performance diagram of the nickel-supported sheet-like molybdenum carbide / carbon two-dimensional composite material prepared in Example 1;

[0021] Figure 4 This is a waveform absorption performance diagram of the nickel-supported sheet-like molybdenum carbide / carbon two-dimensional composite material prepared in Example 2;

[0022] Figure 5 This is a waveform absorption performance diagram of the nickel-supported sheet molybdenum carbide / carbon two-dimensional composite material prepared in Example 3. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1

[0025] 1. According to m 三羟甲基氨基甲烷 :m 盐酸 =1:0.29, dissolve tris(hydroxymethyl)aminomethane and concentrated hydrochloric acid in deionized water, then according to m 磷钼酸 :m 十二烷基硫酸钠 :m 盐酸多巴胺 = 1:3:1, phosphomolybdic acid, sodium dodecyl sulfate and dopamine hydrochloride were dissolved in the above solution, stirred at room temperature for 10 h, and the product was collected by centrifugation and washing to obtain phosphomolybdic acid-polydopamine nanosheets;

[0026] 2. According to m 磷钼酸-聚多巴胺纳米片 :m 氯化镍 :m 氯化铵 :m 氨水 =2:2:1:3.6, dissolve the phosphomolybdic acid-polydopamine nanosheets obtained in step 1, nickel chloride, ammonium chloride and ammonia in deionized water, stir for 30 min, transfer to 100 ml hydrothermal reactor and react at 120 °C for 6 h, collect the product by centrifugation and washing to obtain phosphomolybdic acid-polydopamine-nickel chloride nanosheets;

[0027] 3. Place the phosphomolybdic acid-polydopamine-nickel chloride nanosheets obtained in step 2 into a tube furnace under nitrogen protection, and heat them at 700℃ for 2 hours at a heating rate of 5℃ / min. After cooling with the furnace, nickel-supported sheet molybdenum carbide / carbon two-dimensional composite material is obtained.

[0028] The powder product from Example 1 was uniformly mixed with solid paraffin at a mass ratio of 1:9, and a tightly packed coaxial sample was formed using a mold. The sample had an outer diameter of 7.00 mm, an inner diameter of 3.04 mm, and a thickness of approximately 2 mm. Its electromagnetic parameters were tested using a vector network analyzer (HP8720ES) at a frequency of 2-18 GHz. The absorption performance was calculated, and its performance graph is shown below. Figure 3 As shown, the sample achieved a maximum absorption of -65.48dB with a matching thickness of 2.4mm and a frequency of 15.92GHz, and obtained an effective absorption bandwidth of 4.88GHz.

[0029] The XRD pattern of the product in Example 1 is shown below. Figure 1 ,Depend on Figure 1It can be seen that the product contains Mo2C and Ni nanoparticles. The TEM spectrum of the product in Example 1 is shown below. Figure 2 ,Depend on Figure 2 As can be seen from ab, the product exhibits a sheet-like structure with relatively uniform size, and nickel nanoparticles are uniformly loaded on the nanosheets. Figure 2 The HR-TEM spectrum of cd showed the crystal features on the surface of the nanosheets, and the (101) crystal plane of Mo2C and the (111) crystal plane of Ni could be observed respectively; indicating that Ni has been successfully loaded on the nanosheets and that Mo2C has been successfully synthesized.

[0030] Example 2

[0031] 1. According to m 三羟甲基氨基甲烷 :m 盐酸 =1:0.25, dissolve tris(hydroxymethyl)aminomethane and concentrated hydrochloric acid in deionized water, then according to m 磷钼酸 :m 十二烷基硫酸钠 :m 盐酸多巴胺 = 1:3:1, phosphomolybdic acid, sodium dodecyl sulfate and dopamine hydrochloride were dissolved in the above solution, stirred at room temperature for 10 h, and the product was collected by centrifugation and washing to obtain phosphomolybdic acid-polydopamine nanosheets;

[0032] 2. According to m 磷钼酸-聚多巴胺纳米片 :m 氯化镍 :m 氯化铵 :m 氨水 =2:2:1:3.6, dissolve the phosphomolybdic acid-polydopamine nanosheets obtained in step 1, nickel chloride, ammonium chloride and ammonia in deionized water, stir for 30 min, transfer to 100 ml hydrothermal reactor and react at 120 °C for 6 h, collect the product by centrifugation and washing to obtain phosphomolybdic acid-polydopamine-nickel chloride nanosheets;

[0033] 3. Place the phosphomolybdic acid-polydopamine-nickel chloride nanosheets obtained in step 2 into a tube furnace under nitrogen protection, and heat them at 700℃ for 2 hours at a heating rate of 5℃ / min. After cooling with the furnace, nickel-supported sheet molybdenum carbide / carbon two-dimensional composite material is obtained.

[0034] The powder product from Example 2 was uniformly mixed with solid paraffin at a mass ratio of 1:9, and a tightly packed coaxial sample was formed using a mold. The sample had an outer diameter of 7.00 mm, an inner diameter of 3.04 mm, and a thickness of approximately 2 mm. Its electromagnetic parameters were tested using a vector network analyzer (HP8720ES) at a frequency of 2-18 GHz. The absorption performance was calculated, and its absorption performance is as follows: Figure 4 As shown, the sample achieved a maximum absorption of -46.85dB when matched with a thickness of 2.47mm and a frequency of 16.64GHz.

[0035] The XRD pattern of the product in Example 2 is shown below.Figure 1 The products are mainly Mo2C and Ni nanoparticles, the same as the products in Example 1.

[0036] Example 3

[0037] 1. According to m 三羟甲基氨基甲烷 :m 盐酸 =1:0.18, dissolve tris(hydroxymethyl)aminomethane and concentrated hydrochloric acid in deionized water, then according to m 磷钼酸 :m 十二烷基硫酸钠 :m 盐酸多巴胺 = 1:3:1, phosphomolybdic acid, sodium dodecyl sulfate and dopamine hydrochloride were dissolved in the above solution, stirred at room temperature for 10 h, and the product was collected by centrifugation and washing to obtain phosphomolybdic acid-polydopamine nanosheets;

[0038] 2. According to m 磷钼酸-聚多巴胺纳米片 :m 氯化镍 :m 氯化铵 :m 氨水 =2:2:1:3.6, dissolve the phosphomolybdic acid-polydopamine nanosheets obtained in step 1, nickel chloride, ammonium chloride and ammonia in deionized water, stir for 30 min, transfer to 100 ml hydrothermal reactor and react at 120 °C for 6 h, collect the product by centrifugation and washing to obtain phosphomolybdic acid-polydopamine-nickel chloride nanosheets;

[0039] 3. Place the phosphomolybdic acid-polydopamine-nickel chloride nanosheets obtained in step 2 into a tube furnace under nitrogen protection, and heat them at 700℃ for 2 hours at a heating rate of 5℃ / min. After cooling with the furnace, nickel-supported sheet molybdenum carbide / carbon two-dimensional composite material is obtained.

[0040] The powder product from Example 3 was uniformly mixed with solid paraffin at a mass ratio of 1:9, and a tightly packed coaxial sample was formed using a mold. The sample had an outer diameter of 7.00 mm, an inner diameter of 3.04 mm, and a thickness of approximately 2 mm. Its electromagnetic parameters were tested using a vector network analyzer (HP8720ES) at a frequency of 2-18 GHz. The absorption performance was calculated, and its absorption performance is as follows: Figure 5 As shown, the sample achieved a maximum absorption of -12.66 dB when matched with a thickness of 3.0 mm and a frequency of 13.76 GHz.

[0041] The XRD pattern of the product in Example 3 is shown below. Figure 1 The products are mainly Mo2C and Ni nanoparticles, which are the same as the products in Examples 1 and 2.

[0042] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations and substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A carbon-based composite microwave absorbing material, characterized in that: The carbon-based composite microwave absorbing material comprises nickel nanoparticles and molybdenum carbide / carbon nanosheets, wherein the nickel nanoparticles are uniformly loaded on the molybdenum carbide / carbon nanosheets.

2. The carbon-based composite microwave absorbing material as described in claim 1, characterized in that: The carbon-based composite microwave absorbing material is a nickel-loaded sheet-like molybdenum carbide / carbon two-dimensional composite microwave absorbing material.

3. The carbon-based composite microwave absorbing material as described in claim 1, characterized in that: The carbon-based composite microwave absorbing material is a multiphase, polycrystalline, conductivity-dielectric-magnetic loss synergistic composite microwave absorbing material.

4. The carbon-based composite microwave absorbing material according to any one of claims 1, 2, and 3, characterized in that: The carbon-based composite absorbing material absorbs electromagnetic waves.

5. A method for preparing the carbon-based composite microwave absorbing material as described in claim 1, characterized in that: Nickel-supported sheet-like molybdenum carbide / carbon two-dimensional composite microwave absorbing material was prepared using a supramolecular self-assembly-hydrothermal-high-temperature carbonization method; the specific steps are as follows. S1 according to m 三羟甲基氨基甲烷 :m 盐酸 =1:(0.18, 0.25, 0.29), dissolve tris(hydroxymethyl)aminomethane and concentrated hydrochloric acid in deionized water, then according to m 磷钼酸 :m 十二烷基硫酸钠 :m 盐酸多巴胺 = 1:3:1, phosphomolybdic acid, sodium dodecyl sulfate and dopamine hydrochloride were dissolved in the above solution, stirred at room temperature for 10 h, and the product was collected by centrifugation and washing to obtain phosphomolybdic acid-polydopamine nanosheets; S2 according to m 磷钼酸-聚多巴胺纳米片 :m 氯化镍 :m 氯化铵 :m 氨水 =2:2:1:3.6, dissolve the phosphomolybdic acid-polydopamine nanosheets obtained in S1, nickel chloride, ammonium chloride and ammonia in deionized water, stir for 30 min, transfer to 100 ml hydrothermal reactor and react at 120 °C for 6 h, collect the product by centrifugation and washing to obtain phosphomolybdic acid-polydopamine-nickel chloride nanosheets; S3: The phosphomolybdic acid-polydopamine-nickel chloride nanosheets obtained in S2 were placed in a tube furnace under nitrogen protection and held at 700°C for 2 hours at a heating rate of 5°C / min. After cooling in the furnace, nickel-supported sheet molybdenum carbide / carbon two-dimensional composite material was obtained.

6. The preparation method according to claim 5, characterized in that: The nickel-supported sheet-like molybdenum carbide / carbon two-dimensional composite material is mainly composed of amorphous carbon, molybdenum carbide nanoparticles, and nickel nanoparticles.

7. The preparation method according to claim 5 or 6, characterized in that: Uniformly sized phosphomolybdic acid-polydopamine nanosheets were synthesized using a simple supramolecular self-assembly method. Nickel nanoparticles were then loaded onto molybdenum carbide / carbon nanosheets using a hydrothermal-high temperature carbonization method, resulting in a multiphase, polymorphic nickel-loaded sheet-like molybdenum carbide / carbon two-dimensional composite material.

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