Preparation method and application of CoNi alloy nanoparticle doped double-shell hollow carbon material
CoNi alloy nanoparticle-doped double-shell hollow carbon materials were prepared by a chemically driven synthesis method, which solved the problem of limited electromagnetic wave absorption performance of carbon materials, and achieved lightweight and efficient electromagnetic wave absorption, exhibiting excellent electromagnetic wave absorption performance.
Patent Information
- Application Number
- CN202511810457.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-03
- Publication Date
- 2026-04-10
AI Technical Summary
The electromagnetic wave absorption performance of existing carbon materials is limited, mainly due to the simple loss mechanism and insufficient impedance matching. Furthermore, traditional research on magnetoelectric coupling strategies mostly focuses on physical mixing or simple coating, lacking precise control over multi-heterogeneous interface materials.
By using a chemically driven synthesis method, CoNi alloy nanoparticles are in situ doped into a carbon matrix to form multiple heterogeneous interfaces. Combined with ion exchange strategy and template etching technology, CoNi alloy nanoparticle-doped double-shell hollow carbon materials are prepared. The heterogeneous interfaces and defect structures of the materials are precisely controlled to construct a continuous three-dimensional conductive network.
It significantly enhances the absorption performance of electromagnetic waves, achieves lightweight materials and functional unit load, improves conductivity loss capability, expands the propagation path of electromagnetic waves, and demonstrates excellent electromagnetic wave absorption performance, especially in terms of thinness, lightness, and wide width.
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Abstract
Description
TECHNICAL FIELD
[0001] The application relates to a preparation method of CoNi alloy nanoparticle doped double-shell hollow carbon materials and application thereof, and belongs to the technical field of nanomaterial preparation and electromagnetic wave absorption application. BACKGROUND
[0002] With the rapid development of wireless communication technology and high-integration electronic equipment, emerging electromagnetic applications such as fifth-generation (5G) and sixth-generation (6G) communication technology, artificial intelligence and medical equipment facilitate people's life but also bring more electromagnetic pollution, which threatens human health and equipment safety. Electromagnetic wave absorption materials, referred to as wave-absorbing materials, can efficiently dissipate the energy of incident electromagnetic waves as heat or other forms of energy inside the material. Therefore, it is an urgent need to develop high-performance electromagnetic wave absorption materials.
[0003] Carbon materials have the advantages of low cost, light weight and adjustable dielectric properties, and selecting carbon materials as the matrix can completely meet the application requirements of thinness and lightness in the wave-absorbing field. High-performance wave-absorbing materials often have significant advantages in micro-morphology design, and carbon materials have structural diversity, which can completely meet various microstructures. Among many nano microstructures, the double-shell hollow structure shows great potential due to its unique "shell-cavity-shell-cavity" alternating structure and low density characteristics. This structure not only effectively prolongs the propagation path of electromagnetic waves, enhances energy dissipation through multiple reflections and scattering, but also provides an ideal platform for further realizing material lightness and functional unit loading. In addition, unlike most double-shell structures which rely on template preparation methods, the double-shell hollow carbon materials obtained by this simple and efficient method greatly reduce time and economic costs, and have great research and application value.
[0004] However, due to the single loss mechanism and insufficient impedance matching of carbon materials, the wave-absorbing performance is still limited. In view of this loss problem, the research of magnetic-electric coupling has begun to enter the research field. Therefore, it is of great advantage to in-situ dope CoNi alloy nanoparticles as active components in the carbon matrix. The metal particles and the surrounding carbon matrix form a "metal-carbon" heterojunction. Interface polarization occurs at the micro level, greatly enriching the electromagnetic loss mechanism. At present, the research of magnetic-electric coupling strategy still stays at the physical mixing or simple coating level, so it is of great advantage to synthesize nano materials with multiple heterojunctions through chemical driving. In addition, the advantage of chemical driving synthesis strategy is that it can realize precise control of interface type, density and chemical environment from the growth dynamics and thermodynamics level. Therefore, how to precisely control the multi-heterojunction materials through a stable and repeatable chemical driving synthesis process to establish a stable "process-structure-performance" relationship is of great research and application value for microstructure design and practical application. SUMMARY
[0005] One of the objectives of the present application is to provide a simple and efficient method for preparing double-shell hollow carbon structures at low cost.
[0006] The objective of the present application is achieved by the following technical solutions.
[0007] A method for preparing CoNi alloy nanoparticle-doped double-shell hollow carbon material, comprising the following steps:
[0008] (1) 3-amino phenol and formaldehyde solution are added to an ammonia solution to perform a polycondensation reaction to synthesize phenolic resin spheres, and a single-shell hollow phenolic sphere structure is obtained by selective etching of N,N-dimethylformamide;
[0009] (2) The single-shell hollow phenolic sphere structure is again placed in a mixed solution of 3-amino phenol, ammonia solution and formaldehyde solution to perform a reaction, and then a double-shell hollow phenolic structure is obtained by etching of N,N-dimethylformamide;
[0010] (3) The double-shell hollow phenolic structure is dried, dispersed in a methanol solution by ultrasonic dispersion, then cobalt nitrate hexahydrate (Co(NO3)2·6H2O) is added and stirred, then a methanol solution in which 2-methylimidazole is dissolved is added and stirred at low temperature, and after the reaction, the product is centrifuged, washed and dried;
[0011] (4) The product collected by centrifugation in step (3) is dried, dispersed in an ethanol solution by ultrasonic dispersion, then an ethanol solution in which nickel nitrate hexahydrate (Ni(NO3)2·6H2O) is dissolved is poured into the ethanol solution in which the product is dispersed and stirred, then the mixed solution is placed in an autoclave and reacted at high temperature and high pressure, and after the reaction, the product is centrifuged, washed and dried;
[0012] (5) The product collected by centrifugation in step (4) is dried, then placed in a high-temperature tube furnace to perform vacuum annealing, and a CoNi alloy nanoparticle-doped double-shell hollow carbon material is obtained.
[0013] In step (2), the mass of 3-amino phenol, the volume of formaldehyde solution and the volume of ammonia solution added are 2 times the mass of 3-amino phenol, the volume of formaldehyde solution and the volume of ammonia solution added in step (1), respectively.
[0014] In some embodiments of the present application, in step (1), 0.2 g of 3-amino phenol, 0.2 ml of formaldehyde solution, 60 ml of ammonia solution and 9 of pH are added, and the polycondensation reaction time is 28-32 minutes.
[0015] In step (1), 40 ml of N,N-dimethylformamide is added, and the etching reaction time is 28-32 minutes.
[0016] In some specific embodiments of the present application, the 3-amino phenol added in step (2) is 0.4 g, the formaldehyde solution is 0.4 ml, the ammonia solution is 120 ml, the pH is 9, and the polycondensation reaction time is 28-32 minutes.
[0017] In some specific embodiments of the present application, the N,N-dimethylformamide added in step (2) is 80 ml, and the etching reaction time is 28-32 minutes.
[0018] In some specific embodiments of the present application, in step (3), the product collected by centrifugation in step (2) is 0.2 g, which is dispersed in 50 ml of a methanol solution, Co(NO3)2·6H2O is added, the reaction temperature is 5-10°C, and the stirring time is 12-15 h.
[0019] In some specific embodiments of the present application, in step (3), the 2-methyl imidazole added is 0.82 g, and the stirring time is 24 h.
[0020] In some specific embodiments of the present application, in step (4), the product collected by centrifugation in step (3) is 0.15 g, which is ultrasonically dispersed in 250 ml of an ethanol solution, the stirring time is 28-32 minutes, Ni(NO3)2·6H2O is added, the ethanol solution is 250 ml, the reaction temperature is 80°C, and the reaction time is 6 h.
[0021] In some specific embodiments of the present application, in step (5), the annealing is performed at 600-800°C in N2, the heating rate is 2°C / min, and the holding time is 2 h.
[0022] The present application also provides a wave-absorbing material comprising the CoNi alloy nanoparticle-doped double-shell hollow carbon material prepared by the above method.
[0023] The present application has the following advantages:
[0024] (1) The preparation method of the present application has the characteristics of simplicity, high efficiency and low cost. From the beginning of preparation to the double-shell hollow structure, the time spent is very small, and the operation is also simple. The principle is that the difference in internal / external cross-linking degree caused by the spontaneous formation of spherical phenolic small molecules in an alkaline environment, and the internal low cross-linking degree component is dissolved by N,N-dimethylformamide.
[0025] (2) The preparation method of the present application uses a double-shell structure as a main template, and through the process of sequential introduction and sequential transformation of the template, CoNi alloy nanoparticles are successfully doped in the double-shell hollow structure as active components in situ. The ingenious etching treatment is carried out by ion exchange strategy. The specific principle is that the protons produced by the hydrolysis of nickel nitrate hexahydrate (Ni(NO3)2·6H2O) cut the Co-N coordination bonds in ZIF-67, and the released Co2+ with free Ni 3+ (Ni 2+ combined with O2 and NO3 - oxidation) to form a flaky template, by precisely controlling the concentration of reactants, carefully controlling the chemical reaction kinetics process, inducing the material structure to evolve controllably, and then effectively adjusting its heterojunction and defect structure.
[0026] (3) The CoNi alloy nanoparticle doped double-shell hollow carbon material prepared by the preparation method has a double-shell hollow structure, which can reduce the material density, increase the volume ratio of the same mass, and construct a continuous three-dimensional conductive network in the material, so that electrons can be efficiently migrated along the carbon skeleton. At the same time, the alloy particles uniformly dispersed in the network further provide a channel for electron tunneling transition, which significantly enhances the overall electrical conductivity loss capacity.
[0027] (4) The CoNi alloy nanoparticle doped double-shell hollow carbon material prepared by the preparation method has a CoNi alloy nanoparticle filling amount of 27.5wt%, is stirred with paraffin and is molded into a coaxial ring with an outer diameter of 7.00mm and an inner diameter of 3.04mm, and exhibits an effective absorption bandwidth of 6.47GHz at a thickness of 2.13mm, showing excellent electromagnetic wave absorption performance. BRIEF DESCRIPTION OF DRAWINGS
[0028] Figure 1 It is a TEM diagram of the CoNi alloy nanoparticle doped double-shell hollow carbon material of the present application.
[0029] Figure 2 It is the electromagnetic parameters of the double-shell hollow carbon nanomaterial and the CoNi alloy nanoparticle doped double-shell hollow carbon material of the present application.
[0030] Figure 3 It is the reflection loss of the double-shell hollow carbon nanomaterial and the CoNi alloy nanoparticle doped double-shell hollow carbon material of the present application. DETAILED DESCRIPTION
[0031] The preferred embodiments of the present application will be described in detail below.
[0032] Example 1 (CoNi alloy nanoparticle doped double-shell hollow carbon material)
[0033] (1) Pour 60ml of deionized water into a 100ml capacity beaker, and drop in an ammonia solution until the PH is 9. Add 3-amino phenol 0.2g to the solution, dissolve, and then drop in 0.2ml of formaldehyde solution, and stir for 30 minutes. Then add 40ml of N,N-dimethylformamide and react for 30 minutes, and then centrifuge and wash after reaction;
[0034] (2) The centrifuged product was placed in 120 ml of deionized water, and an ammonia solution was added dropwise until the pH was 9. 3-amino phenol 0.4 g was added to the solution, and after dissolution, 0.4 ml of formaldehyde solution was added dropwise, and stirred for 30 minutes. Then 80 ml of N,N-dimethylformamide was added and reacted for 30 minutes, and after reaction, centrifuged, washed and dried;
[0035] (3) 0.2 g of the product collected by centrifugation in step (2) was dried and placed in 50 ml of methanol solution and ultrasonically dispersed, then 0.5 g of Co(NO3)2·6H2O was added and stirred for 12 h, 50 ml of methanol solution in which 0.82 g of 2-methylimidazole was dissolved was added, and the solution was transferred to a low-temperature environment and stirred for 24 h;
[0036] (4) 0.15 g of the product collected by centrifugation in step (3) was dried and placed in 250 ml of ethanol solution and ultrasonically dispersed, 250 ml of ethanol solution in which 1.45 g of Ni(NO3)2·6H2O was dissolved was added and stirred for 30 min, and the mixed solution was placed in an autoclave and incubated at 80°C for 6 h;
[0037] (5) The product collected by centrifugation was dried and then placed in a high-temperature tube furnace, incubated at 600-800°C under a nitrogen atmosphere for 2 h, to obtain a CoNi alloy nanoparticle-doped double-shell hollow carbon material.
[0038] Example 2 (CoNi alloy nanoparticle-doped double-shell hollow carbon material)
[0039] The preparation method was the same as in Example 1, except that in (4) the mass of Ni(NO3)2·6H2O added was 0.58 g.
[0040] Example 3 (CoNi alloy nanoparticle-doped double-shell hollow carbon material)
[0041] The preparation method was the same as in Example 1, except that in (4) the mass of Ni(NO3)2·6H2O was 2.32 g.
[0042] Comparative Example (double-shell hollow carbon nanomaterial)
[0043] The preparation method used steps (1) and (2) in Example 1, and then after drying, the product was placed in a high-temperature tube furnace and incubated at 600-800°C under a nitrogen atmosphere for 2 h, to obtain a double-shell hollow carbon nanomaterial.
[0044] The CoNi alloy nanoparticle-doped double-shell hollow carbon material was subjected to TEM testing. As shown in FIG. 1, the material had a double-shell structure, and the CoNi alloy nanoparticles were uniformly distributed in the inner shell. Figure 1As shown, the sample is composed of double-shell hollow carbon and nanoparticles, the carbon sphere size is about 500 nm, there is a clear gap between the inner and outer shells, and the carbon shell layer plays an important role in preventing further agglomeration of alloy particles, which has a beneficial effect on the subsequent improvement of the performance of the material.
[0045] The electromagnetic parameters of the double-shell hollow carbon nanomaterial and the CoNi alloy nanoparticle-doped double-shell hollow carbon material were tested. Figure 2 As shown, after doping alloy particles, the dielectric parameters of the nanomaterial are improved to a certain extent, indicating that it has stronger dielectric storage and dissipation capacity. Due to almost the same double-shell carbon matrix properties, the difference in dielectric performance mainly comes from the doping of alloy particles. In addition, it can be found from the imaginary part of the dielectric constant that the embodiment shows several more significant fluctuations at 5.7-5.9, 9.6-9.7 and 12.5-12.8 GHz than the control example, such behavior is usually due to the polarization relaxation process inside the material. This indicates that the alloy particles bring more significant dielectric polarization loss. Moreover, due to the magnetism brought by the alloy particles, although the real part and the imaginary part of the magnetic permeability are close to 1 and 0 respectively, the contribution of magnetic loss is small, but the improvement of impedance matching cannot be ignored.
[0046] The wave absorption performance was calculated according to the measured electromagnetic parameters. Figure 3 As shown, by reasonably controlling the chemical reaction kinetics of the double-shell carbon nanomaterial, both Example 1 and Example 2 achieve an effective absorption bandwidth greater than the original double-shell carbon structure at a thinner thickness, and the effective absorption bandwidth of Example 1 even achieves full coverage of the Ku band, reaching an ultra-wide absorption of 6.47 GHz, meeting the characteristics of lightness, thinness and wide bandwidth. The excellent wave absorption performance is due to the comprehensive promotion of the dielectric performance by factors such as double-shell hollow structure and magnetic-electric coupling. In addition, the heterojunction and defect construction also enrich the polarization loss of the material.
[0047] In summary, the embodiment of the present application exhibits a strategy of double-shell space confinement combined with sequential template level, which skillfully controls the chemical reaction kinetics under the ion exchange strategy and the subsequent thermodynamic control in the preparation, and cooperatively controls from different angles to dope the double-shell hollow carbon material with CoNi alloy nanoparticles. By comparing with the double-shell hollow carbon nanomaterial of the control example, it can be seen that the double-shell hollow carbon material doped with CoNi alloy nanoparticles has excellent wave absorption application prospect.
Claims
1. A method for preparing CoNi alloy nanoparticle doped double-shell hollow carbon material, characterized in that, The method comprises the following steps: (1) adding 3-amino phenol and formaldehyde solution into an ammonia solution to perform a condensation reaction to synthesize a phenolic resin ball, and obtaining a single-shell hollow phenolic resin ball structure through selective etching of N,N-dimethylformamide; (2) placing the single-shell hollow phenolic resin ball structure into a mixed solution of 3-amino phenol, ammonia solution and formaldehyde solution to perform a reaction, and then obtaining a double-shell hollow phenolic resin structure through etching of N,N-dimethylformamide; (3) drying the double-shell hollow phenolic resin structure, dispersing the double-shell hollow phenolic resin structure in a methanol solution through ultrasonic dispersion, then adding cobalt nitrate hexahydrate (Co(NO3)2·6H2O) and stirring, then adding a methanol solution in which 2-methyl imidazole is dissolved and stirring at a low temperature, and then performing centrifugal washing and drying after the reaction; (4) drying the product collected through centrifugal washing in step (3), dispersing the product in an ethanol solution through ultrasonic dispersion, then adding a nickel nitrate hexahydrate (Ni(NO3)2·6H2O) ethanol solution into the ethanol solution in which the product is dispersed and stirring, then placing the mixed solution into an autoclave to perform a reaction under high temperature and high pressure, and then performing centrifugal washing and drying after the reaction; (5) drying the product collected through centrifugal washing in step (4), and then placing the product into a high-temperature tube furnace to perform vacuum annealing, so as to obtain a CoNi alloy nanoparticle doped double-shell hollow carbon material.
2. The method for preparing CoNi alloy nanoparticle doped double-shell hollow carbon material according to claim 1, characterized in that, The mass of 3-amino phenol added in step (2), the volume of formaldehyde solution and the volume of ammonia solution are respectively twice the mass of 3-amino phenol, the volume of formaldehyde solution and the volume of ammonia solution added in step (1).
3. The method for preparing CoNi alloy nanoparticle-doped double-shell hollow carbon material as described in claim 1, characterized in that, In step (1), the added 3-amino phenol is 0.2 g, the added formaldehyde solution is 0.2 ml, the added ammonia solution is 60 ml, the pH is 9, and the condensation reaction time is 28-32 minutes.
4. The method for preparing CoNi alloy nanoparticle-doped double-shell hollow carbon material as described in claim 1, characterized in that, In step (1), the added N,N-dimethylformamide is 40 ml, and the etching reaction time is 28-32 minutes.
5. The method for preparing CoNi alloy nanoparticle-doped double-shell hollow carbon material as described in claim 1, characterized in that, In step (2), the added 3-amino phenol is 0.4 g, the added formaldehyde solution is 0.4 ml, the added ammonia solution is 120 ml, the pH is 9, and the condensation reaction time is 28-32 minutes.
6. The method of claim 1, wherein the CoNi alloy nanoparticle-doped double- shell hollow carbon material is prepared by the steps of: In step (2), the added N,N-dimethylformamide is 80 ml, and the etching reaction time is 28-32 minutes.
7. The method of claim 1, wherein the CoNi alloy nanoparticle-doped double- shell hollow carbon material is prepared by the steps of: preparing a CoNi alloy nanoparticle-doped double-shell hollow carbon material by the method of claim 1; and washing the CoNi alloy nanoparticle-doped double-shell hollow carbon material with distilled water. In step (3), the product collected through centrifugal washing in step (2) is 0.2 g, which is dispersed in 50 ml of methanol solution, the added Co(NO3)2·6H2O is 0.5 g, the reaction temperature is 5-10 ℃, and the stirring time is 12-15 h.
8. The method of claim 1, wherein the CoNi alloy nanoparticle-doped double- shell hollow carbon material is prepared by the steps of: preparing a CoNi alloy nanoparticle-doped double-shell hollow carbon material by the method of claim 1; and washing the CoNi alloy nanoparticle-doped double-shell hollow carbon material with distilled water. In step (4), the product collected through centrifugal washing in step (3) is 0.15 g, which is dispersed in 250 ml of ethanol solution through ultrasonic dispersion, the stirring time is 28-32 minutes, the added Ni(NO3)2·6H2O is 0.58-2.32 g, the added ethanol solution is 250 ml, the reaction temperature is 80 ℃, and the reaction time is 6 h.
9. The method of claim 1, wherein the CoNi alloy nanoparticle-doped double- shell hollow carbon material is prepared by the steps of: preparing a CoNi alloy nanoparticle-doped double-shell hollow carbon material by the method of claim 1; and washing the CoNi alloy nanoparticle-doped double-shell hollow carbon material with distilled water. In step (5), the annealing is performed in N2 at 600-800 ℃, the heating rate is 2 ℃ / min, and the holding time is 2 h.
10. A wave-absorbing material, characterized by, The CoNi alloy nanoparticle doped double-shell hollow carbon material prepared by the method of any one of claims 1-9.