CN111646458B - Preparation of nitrogen-doped nanosheets or Fe-loaded nanoparticles 2 O 3 Method for graphite structure of nano-particles - Google Patents

Preparation of nitrogen-doped nanosheets or Fe-loaded nanoparticles 2 O 3 Method for graphite structure of nano-particles Download PDF

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CN111646458B
CN111646458B CN202010386384.0A CN202010386384A CN111646458B CN 111646458 B CN111646458 B CN 111646458B CN 202010386384 A CN202010386384 A CN 202010386384A CN 111646458 B CN111646458 B CN 111646458B
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马嵩
李帅贞
华安
耿殿禹
雷子璇
刘伟
张志东
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Institute of Metal Research of CAS
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Abstract

The invention aims to provide an N-doped nano-sheet graphite structure or a surface loaded Fe 2 O 3 A process for preparing N-doped nano-sheet graphite structure of nanoparticles includes such steps as high-temp plasma arc evaporation to obtain high-purity graphite rod as cathode and high-purity Fe powder and high-purity graphite powder as anode, vacuumizing the arc furnace, introducing acetonitrile as carbon and nitrogen sources, and collecting the deposit on the inner surface of reaction cavity to obtain the folded N-doped nano-sheet graphite or uniformly dispersing Fe on it 2 O 3 A nanoparticle composite. The products can be prepared in a large scale by a simple and harmless high-temperature plasma arc evaporation method without any reaction gas, the nano-sheet graphite is disordered and full of a large number of defects due to the doping of the N element, and the nano-sheet graphite is induced to generate new performance, so that the nano-sheet graphite can be widely applied to various fields such as wave absorption and the like.

Description

Preparation of Nitrogen-doped nanosheets or Fe-loaded nanoparticles 2 O 3 Method for graphite structure of nano-particles
Technical Field
The invention belongs to the field of materials, and relates to a thin graphiteA novel synthesis technology of lamella, which utilizes a plasma arc evaporation method and provides a method for in-situ mass production of N-doped nano-lamellar graphite structure or Fe-loaded nano-lamellar graphite structure by introducing catalytic gas acetonitrile in an in-situ state 2 O 3 A preparation method of N-doped nano-sheet graphite structure of nano particles.
Background
Since 2004, single-layer graphene was first prepared, and the research gate of graphene was opened. Graphene is a two-dimensional carbon material with a thickness of only one carbon atom formed by close packing of a single layer of carbon atoms. It produces a number of specific properties by virtue of good crystallinity, exceptional stability, and its particular structure. The thermal conductivity of the graphene is more than 4000W/m.K at room temperature, and the specific surface area is close to 2630m 2 The extremely high strength and the extremely low density make the material have wide application in electronic devices, physics, chemistry and the like. For example, the graphene can be applied to the fields of battery electrodes, super capacitors, hydrogen storage, adsorption, electrocatalysis, electromagnetic shielding and the like.
However, the use of low-cost production of high-quality graphene or graphene-like nano-sheet graphite structures is one of the important reasons that prevent their widespread use. In recent ten years, a production and preparation technology of graphene is continuously introduced, for example, by a dissolution thermal method, and another method for preparing graphene uses various aromatic hydrocarbons to synthesize graphene, which not only extends the production path of graphene, but also has a great influence on the research of the physical properties and chemical synthesis of graphene. High-quality graphene can be produced by using a mechanical stripping method, but large-batch production is extremely difficult to realize; the method has the advantages of long reaction time, complex process, relatively low dehydrogenation efficiency, easy environmental pollution and structural defects. The oxidation-reduction method and the Chemical Vapor Deposition (CVD) method are most commonly used to prepare graphene, however, the CVD method has high cost and complicated process, and the oxidation-reduction method wastes time and the synthesized graphene has a large degree of defects. Patent CN104118870a discloses a method for preparing nitrogen-doped graphene by using a direct current arc method. Firstly, a direct current arc method is used, graphite rods are used as two poles of an electric arc furnace, mixed gas of nitrogen and hydrogen is introduced into the electric arc furnace, the discharge current is 80-200A, the graphite rods at the two poles are continuously consumed in the reaction process, and finally N-doped graphene is collected on the inner wall. The percentage content of N atoms doped in the obtained graphene is 0.3-2%. The technical scheme provided by the method has the advantages of simple equipment, low production cost and high preparation speed, and can meet the requirement of mass production. However, the nitrogen content of the nitrogen-doped graphene obtained by the method is low, subsequent treatment is required, and the wave-absorbing effect cannot meet the application requirement.
The preparation of graphene or graphene-like nanosheet graphite structures requires innovation of new preparation methods, and what is particularly proposed here is that the high-temperature plasma arc evaporation method becomes a novel means for preparing graphene or graphene-like nanosheet graphite structures by virtue of the advantages of safety, reliability and simplicity of the method for synthesizing nanocarbon materials, large yield, high quality and the like of the produced nanocarbon materials.
The invention adopts high-temperature plasma arc evaporation technology to prepare a nitrogen-doped nano-sheet graphite structure in situ and load Fe on the surface 2 O 3 The nitrogen-doped nano-sheet graphite structure of the nano-particles has a unique internal structure of equipment and controllable reaction conditions, so that the nano-sheet graphite structure which does not need subsequent treatment, has high purity and has few structural defects can be continuously prepared.
Disclosure of Invention
The invention aims to provide a method for preparing a graphene-like nitrogen-doped nanosheet graphite structure, namely, a high-temperature plasma arc evaporation method is adopted to prepare the wrinkled N-doped nanosheet graphite structure of a large sheet layer, or Fe is uniformly dispersed on the wrinkled N-doped nanosheet graphite structure of the large sheet layer 2 O 3 A nanoparticle composite. The method solves the technical problem of nano-sheet graphite preparation, so that the nano-sheet graphite preparation process is simple, the operation is convenient, the cost is low, the method is safe and reliable, the prepared nano-sheet graphite has high purity and few defects, and the subsequent treatment is not needed.
The technical scheme of the invention is as follows:
preparation of nitrogen-doped nano-sheet graphite structure or loaded Fe 2 O 3 A method of nitrogen doping of nano-particles into a nano-sheet graphite structure, characterized by: the high-temperature plasma arc evaporation method is adopted for preparation, a high-purity graphite rod is used as a cathode, the high-purity graphite rod or a mixed block of high-purity Fe powder and high-purity graphite powder is used as an anode, after the arc furnace is vacuumized, no other reaction gas is needed to be filled, only liquid acetonitrile is introduced, the liquid acetonitrile enters a vacuum cavity and is used as a carbon source and a nitrogen source, and after plasma arc discharge is finished, sediment on the inner wall of the reaction cavity is collected to obtain the high-temperature plasma arc evaporation method.
As a preferred technical scheme:
the percentage content of nitrogen-doped atoms in the obtained product is 2.16at.% to 5.84at.%.
The distance between the cathode and the anode target material is kept between 1mm and 5 mm; the vacuum degree of the electric arc furnace is better than 8 multiplied by 10 -3 Pa; the current of arc discharge is 60A-400A, and the voltage is 17V-100V; the arc holding time is 5min-120min, and the liquid acetonitrile charging amount is 5ml-60ml (the optimal acetonitrile using amount is 30 ml).
The cathode is of a rod body structure with the diameter of 4 mm-10 mm, the end of the cathode graphite rod close to the anode is conical, and the anode is of a rod body structure with the diameter of 4 mm-20 mm.
The purity of the high-purity graphite rod or the high-purity graphite powder is more than or equal to 99.9wt%, and the purity of the high-purity Fe powder is more than or equal to 99.9wt%.
When the anode target material is a mixed block of high-purity Fe powder and high-purity graphite powder, the contents of the two are as follows: 1at percent to 10at percent of high-purity Fe powder and 90at percent to 99at percent of high-purity graphite powder.
The nitrogen-doped nano-sheet graphite structure prepared by the method of the invention or the surface of the nitrogen-doped nano-sheet graphite structure is loaded with Fe 2 O 3 The nitrogen-doped nano-sheet graphite of the nano-particles forms a flaky and relatively disordered graphene-like nano-sheet graphite structure with a plurality of folds due to the doping of N, or spherical nano Fe is uniformly dispersed on the flaky and relatively disordered nano-sheet graphite 2 O 3 Granules, usable as room temperature or evenWave-absorbing material with frequency range of 2GHz-18GHz at low temperature.
The invention has the beneficial effects that:
1. the invention adopts the high-temperature plasma direct current arc evaporation technology to prepare the high-quality nano lamellar graphite, and has the advantages of simple equipment, low production cost, high production efficiency, greenness and no pollution.
2. Scanning electron microscope, transmission electron microscope and Raman spectrum show that the sediment on the inner wall of the product prepared by the method is nano lamellar graphite, the size of the lamellar is 100nm-300nm, the number of layers is 1-5, and the purity is high; the prepared nano-sheet graphite is relatively disordered and has a plurality of defects as determined by ray diffraction (XRD) and Raman (Raman) spectrums.
3. The N-doped nano-sheet graphite sample prepared by the method does not need subsequent treatment.
4. The invention adopts high-temperature plasma arc evaporation technology, the temperature generated by electric arc is higher than 3000 ℃, and liquid acetonitrile (C) is introduced 2 H 3 N) enters a vacuum cavity to be gasified, so that the gas is used as catalytic gas, plasma decomposes the gas into C, H, N atoms and the like, wherein C, H, N atoms are dissolved in a molten anode molten pool due to small size, in the evaporation process, the anode C atoms or C atoms and Fe atoms are promoted to be evaporated in large quantity, and after the atoms leave a high-temperature region, the atoms collide with each other to form an N-doped nanosheet graphite structure or the surface of the atoms is loaded with Fe 2 O 3 An N-doped nano-platelet graphite structure of nanoparticles.
5. The invention introduces liquid acetonitrile (C) 2 H 3 N) as N source relative to N 2 And the gas is used as a nitrogen source, the acetonitrile storage is more convenient, a plurality of safety problems such as gas leakage do not exist, and the N doping amount of the obtained two-dimensional nano graphite sheet structure is more (2.16 at.% to 5.84 at.%), so that the formed graphite sheet has more folds, more disordered structure, more defects and active sites, and larger dielectric relaxation and magnetic loss, and the wave absorbing effect of the material is better.
6. In the range of 2GHz-18GHz, the nitrogen-doped nanosheet layer graphite structure prepared by the method has the advantages that the imaginary part epsilon 'of the dielectric constant is higher than the real part epsilon' (epsilon '/epsilon' > 1), and the dielectric loss performance is better; and when the nitrogenous sample is used as a wave absorbing agent, the nitrogenous sample has good wave absorbing performance in a high-frequency range (16 GHz-18 GHz) under the condition that the content proportion of the nitrogenous sample reaches 50%, the reflection loss approaches-10 dB (equivalent to 90% absorption), and the nitrogenous sample can be used as a very good wave absorbing material under the high-frequency condition.
7. In the range of 4GHz-18GHz, the load Fe prepared by the method of the invention 2 O 3 The nitrogen-doped nano-sheet graphite structure of the nano-particles has good dielectric loss performance, and the dielectric loss factor epsilon 'is far larger than the dielectric energy storage factor epsilon' (when the nitrogen-doped nano-sheet graphite structure contains 50wt.% of loaded nano-Fe 2 O 3 When the N of the particles is doped with the nanosheet graphite structure, epsilon "/epsilon' = 2.64-12.27). And is therefore a good dielectric loss material in this frequency range.
Drawings
FIG. 1X-ray diffraction spectra of N-doped nano-platelet graphite structure of example 1.
Fig. 2 is a transmission electron microscope image of the N-doped nanosheet graphite structure of example 1.
FIG. 3 scanning electron microscope (80000 magnification) of the N-doped nanosheet graphite structure of example 1.
FIG. 4X-ray photoelectron signature spectra of N-doped nanosheet graphite structure of example 1: (a) X-ray photoelectron signature spectrum of C1 s; (b) an X-ray photoelectron signature spectrum of N1 s.
Fig. 5 Raman spectrum of the N-doped nano-graphite sheet structure of example 1 (illustrating that the N-doped nano-graphite sheet has an ordered graphite structure and also has a largely disordered defect structure).
Fig. 6 shows a hysteresis loop of the N-doped nano-sheet graphite structure in example 1at room temperature of 300K.
FIG. 7 shows the variation of electromagnetic parameters with frequency for the nanosheet graphite structures of example 1 in different ratios, with (a) the variation of the real part of the permittivity with frequency, (b) the variation of the imaginary part of the permittivity with frequency, (c) the variation of the real part of the permeability with frequency, and (d) the variation of the imaginary part of the permeability with frequency.
Fig. 8 shows the variation of the reflection loss of the nano-sheet graphite structure of example 1 with frequency, (a) 40% of the reflection loss of the N-doped nano-sheet graphite structure with frequency, (b) 50% of the reflection loss of the N-doped nano-sheet graphite structure with frequency, and (c) 60% of the reflection loss of the N-doped nano-sheet graphite structure with frequency.
FIG. 9 surface loading of Nano Fe in example 2 2 O 3 X-ray diffraction spectra of N-doped nanosheet graphite structures of the particles.
FIG. 10 shows that nano Fe is loaded on the surface in example 2 2 O 3 Transmission electron microscopy of an N-doped nanosheet graphite structure of the particle, (a) a topography; the (b) and (c) are high resolution pictures.
FIG. 11. Surface-loading of nano Fe in example 2 2 O 3 X-ray photoelectron signature spectra of N-doped nanosheet graphitic structure Fe2p 3/2 of the particles.
FIG. 12 surface loading of Nano Fe in example 2 2 O 3 Raman spectra of N-doped nanosheet graphitic structures of the particles.
FIG. 13 example 2 different ratios of Fe 2 O 3 The variation relation of electromagnetic parameters of the N-doped nanosheet graphite structure of @ C with frequency, (a) the variation relation of a real part of dielectric constant with frequency, (b) the variation relation of an imaginary part of dielectric constant with frequency, (C) the variation relation of a real part of magnetic permeability with frequency, (d) the variation relation of an imaginary part of magnetic permeability with frequency, (e) the variation relation of a dielectric loss factor epsilon '/epsilon' with frequency.
Detailed Description
All examples use inert gases (e.g. Ar gas or H) 2 ) Preparing N-doped nano-sheet graphite structure or surface-loaded nano Fe under the condition of only introducing liquid acetonitrile 2 O 3 An N-doped nano-sheet graphite structure of particles.
In the following examples, unless otherwise specified, a graphite electrode having a purity of 99.9wt% was used as a cathode, and a sacrificial anode target material was used which was a graphite rod having a purity of 99.9wt% or a high-purity graphite powder and a high-purity iron powder compact. The catalytic reaction gas used was acetonitrile.
Example 1
Preparing an N-doped nanosheet graphite structure by using a high-temperature plasma arc evaporation technology:
in the plasma arc discharge evaporation process, the consumed anode target material is a high-purity graphite rod with the diameter of 10mm, and the distance between the graphite cathode and the anode target material is 1.5mm. The cavity is vacuumized to 5 multiplied by 10 -3 And (2) introducing 30ml of liquid acetonitrile into the vacuum cavity after Pa, switching on a direct current power supply, adjusting the voltage to 18V-24V, generating plasma arc discharge between the anode target and the cathode to generate arc discharge current 60A, adjusting the working current and the voltage to keep relatively stable in the arc discharge process, keeping the arc for 90 minutes, preparing N-doped nano-sheet graphite in the atmosphere, and collecting a powdery N-doped nano-sheet graphite structure on the inner wall of the vacuum cavity after extracting reaction gas.
Fig. 1 shows an X-ray diffraction pattern (XRD) of the resulting N-doped nanosheet graphite structure, from which it can be seen as a standard peak of N-doped graphene.
Fig. 2 shows a transmission electron microscope photograph of the N-doped nanosheet graphite structure, and it can be seen from fig. 2 that the N-doped nanosheet graphite has a typical folded lamellar structure, is 100nm to 300nm in lamellar distribution, has 1 to 5 layers, and has uneven thickness distribution.
Fig. 3 shows a scanning electron micrograph of the N-doped nanosheet graphite structure, at 80000 x magnification, from which the typical folded lamellar structure characteristic can be seen.
Fig. 4 shows N-doped nanosheet graphite structures at different depths: (a) An X-ray photoelectron characteristic spectrum of C1s, and (b) an X-ray photoelectron characteristic spectrum of N1 s. From the map, the C element has no obvious difference in the binding energy spectrum characteristic peak at the outer surface and the inner depth of the lamellar graphite, which indicates that the C atoms are distributed more uniformly, and the N element has obvious difference in the binding energy spectrum characteristic peak at the outer surface and the inner depth of the lamellar graphite, which indicates that the N atoms are distributed more on the surface and less in the deeper part.
FIG. 5 shows Raman spectra of N-doped nanosheet graphite, indicating two characteristic scattering peaks, D and G, of graphite, each located at 1310.7cm -1 And 1572.8cm -1 The random graphite and the ordered graphite respectively represent the structure of the disordered graphite, and according to the analysis of the front transmission electron microscope photo, the disorder represents that the graphite shell has more defects, and the order represents the ordered distribution of carbon atoms in the graphite shell. And at 2631cm -1 The 2D peak is obvious, which proves the occurrence of the nano-sheet graphite and is the 2D peak is 2700cm from the standard value -1 Compared with the left shift, the sheet layer is thinner.
Fig. 6 indicates the weak ferromagnetic properties of N-doped nanosheet graphite at room temperature, with a saturation magnetization of 0.288emu/g and a coercivity of 153Oe at room temperature.
Fig. 7 shows electromagnetic properties measured at room temperature of 40wt.%,50wt.%,60wt.% of N-doped nanosheet graphite mixed with 60wt.%,50wt.%,40wt.% of paraffin (a medium that does not absorb electromagnetic waves), with a real part of permittivity ∈ 'ranging from 10 to 52 in the 2-18GHz range, an imaginary part of permittivity ∈ "ranging from 10.2 to 74.6 in the 2-18GHz range, a real part of complex permeability μ' ranging from 0.83 to 1.08 in the 2-18GHz range, and an imaginary part of complex permeability μ" ranging from-0.19 to 0.18 in the 2-18GHz range, respectively. Wherein epsilon '/epsilon' > 1 indicates good dielectric loss characteristics, and the ratio (epsilon '/epsilon') is larger than other types of graphene and nano-graphite sheet structures.
Fig. 8 shows the curves of the reflection loss of 40wt.%,50wt.% and 60wt.% N-doped nanosheet graphite as a function of frequency, and the curves show that the nitrogen-containing sample has better wave-absorbing performance in the high-frequency range (16 GHz-18 GHz) and the reflection loss approaches-10 dB (equivalent to 90% absorption) when the nitrogen-containing sample is used in a proportion of 50% from 40wt.% to 60 wt.%. The material has good wave-absorbing effect in a high-frequency range and can be used as a wave-absorbing material in a high-frequency range. But at the same time, the loss is not high but the bandwidth is still quite large at 2GHz-16GHz, and the thinner the nano graphite sheet is, the better the wave absorbing effect is, which shows that the nano sheet layer structure can be in the high frequency range of 2GHz-18GHz and possibly more than 18GHz, and has excellent thin, light, wide frequency band and strong wave absorbing performance.
Example 2
Preparation of surface-loaded nano Fe by high-temperature plasma arc evaporation technology 2 O 3 Particle N-doped nanosheet graphite structure:
in the plasma arc discharge evaporation process, the consumed anode target material is a cylinder which is formed by briquetting high-purity graphite powder (95 at.%) and high-purity iron powder (5 at.%) and has the diameter of 40mm and the thickness of 10mm, and the distance between the graphite cathode and the anode target material is 1.5mm. The cavity is vacuumized to 5 multiplied by 10 -3 After Pa, introducing 30ml of liquid acetonitrile into a plasma arc discharge cavity, switching on a direct current power supply, adjusting the voltage to be 22V-32V, generating arc discharge between an anode target material and a cathode, wherein the current for generating the arc discharge is 60A, adjusting the working current and the voltage to keep relatively stable in the arc discharge process, keeping the arc for 40 minutes, and preparing the surface-loaded nano Fe in the reaction atmosphere 2 O 3 After reaction gas is pumped out from the particle N-doped nano-sheet graphite, powdery nano-Fe loaded on the surface is collected on the inner wall of the vacuum cavity 2 O 3 A particulate N-doped nanosheet graphite structure.
FIG. 9 shows the obtained surface-supported nano Fe 2 O 3 The X-ray diffraction pattern (XRD) of the particle N-doped nano-sheet graphite structure shows that the nano-sheet graphite has characteristic peaks and Fe 2 O 3 Phases and also parts of the smaller impurity phases appear.
FIG. 10 shows the surface loading of nano-Fe 2 O 3 The transmission electron micrograph of the N-doped nano-sheet graphite negative structure of the particles shows that the whole morphology is Fe uniformly dispersed on the thin sheet 2 O 3 Particles are distributed in a flaky shape of 100nm-300nm, the number of layers is 1-3, and the thickness distribution is uniform; the particle size distribution is 5nm-30nm, the particle size is relatively uniform, and the average particle size is about 15 nm.
FIG. 11 shows the surface loading of nano-Fe 2 O 3 Fe2p in N-doped nano-sheet graphite structure of particles 3/2 Outside ofThe surface X-ray photoelectron characteristic spectrum is Fe as shown by the position of the characteristic peak of the spectrum 2 O 3 Fe2p of 3/2 Characteristic peak.
FIG. 12 shows the surface loading of nano-Fe 2 O 3 The Raman spectrum of the N-doped nano-sheet graphite structure of the particles indicates two characteristic scattering peaks D and G of graphite, which are respectively located at 1310.7cm -1 And 1570.6cm -1 The random graphite and the ordered graphite respectively represent the disordered graphite structure, and the disorder represents that the graphite shell has more defects and the ordered represents the ordered distribution of carbon atoms in the graphite shell according to the analysis of the front transmission electron microscope photo. And at 2624.5cm -1 The 2D peak is obvious, which proves the occurrence of the nano-sheet graphite and is the 2D peak is 2700cm from the standard value -1 Compared with the left shift, the sheet layer is thinner.
Fig. 13 shows 40wt.% and 50wt.% of nano-Fe supported, respectively 2 O 3 The N-doped nanosheet graphite structure of the particles, mixed with 60wt.%,50wt.% paraffin (medium that does not absorb electromagnetic waves), has an electromagnetic property measured at room temperature with a real part of permittivity ε ' ranging from 5 to 42 in the range of 4GHz to 18GHz and an imaginary part of permittivity ε "ranging from 20 to 117 in the range of 4 to 18GHz, and it is apparent that the dielectric loss factor (∈"/ε ') ranges from 1.1 to 1.86 or from 2.64 to 12.27, respectively, is quite large, with a real part of complex permeability μ ' ranging from 0.6 to 1.05 in the range of 4GHz to 18GHz and an imaginary part of complex permeability μ "ranging from-0.15 to 0.24 in the range of 4 to 18 GHz.
Example 3
Preparation of surface-loaded nano Fe by high-temperature plasma arc evaporation technology 2 O 3 Particle N-doped nanosheet graphite structure:
in the plasma arc discharge evaporation process, the consumed anode target material is a cylinder which is formed by briquetting high-purity graphite powder (96 at.%) and high-purity iron powder (4 at.%) and has the diameter of 40mm and the thickness of 10mm, and the distance between the graphite cathode and the anode target material is 2mm. The vacuum pumping of the cavity reaches 6.6 multiplied by 10 -3 After Pa, introducing 25ml of liquid acetonitrile into the plasma arc discharge cavity, switching on a direct current power supply, adjusting the voltage to 18V-40V, generating arc discharge between the anode target and the cathode,the current for generating arc discharge is 80A, the working current and the voltage are regulated to be relatively stable in the arc discharge process, the arc holding time is 30 minutes, and the surface-loaded nano Fe is prepared in the reaction atmosphere 2 O 3 After reaction gas is pumped out from the particle N-doped nano-sheet graphite, powdery nano-Fe loaded on the surface is collected on the inner wall of the vacuum cavity 2 O 3 A particulate N-doped nanosheet graphite structure.
Example 4
Preparation of surface-loaded nano Fe by high-temperature plasma arc evaporation technology 2 O 3 Particle N-doped nanosheet graphite structure:
in the plasma arc discharge evaporation process, the consumed anode target material is a cylinder which is formed by briquetting high-purity graphite powder (97 at.%) and high-purity iron powder (3 at.%) and has the diameter of 40mm and the thickness of 10mm, and the distance between a graphite cathode and the anode target material is 1.5mm. The vacuum pumping of the cavity reaches 6.0 multiplied by 10 -3 After Pa, introducing 20ml of liquid acetonitrile into a plasma arc discharge cavity, switching on a direct current power supply, adjusting the voltage to be 25V-55V, generating arc discharge between an anode target material and a cathode, wherein the current for generating the arc discharge is 100A, adjusting the working current and the voltage to keep relatively stable in the arc discharge process, keeping the arc for 18 minutes, and preparing the surface-loaded nano Fe in the reaction atmosphere 2 O 3 After reaction gas is pumped out from the particle N-doped nano-sheet layer graphite, powdery nano Fe loaded on the surface of the nano-sheet layer graphite is collected on the inner wall of the vacuum cavity 2 O 3 A particulate N-doped nanosheet graphite structure.
According to the experimental result, in the examples 3 and 4, some experimental parameters are changed, so that the finally obtained surface is loaded with nano Fe 2 O 3 The dielectric loss factor (. Epsilon. "/ε ') of the particulate N-doped nanosheet graphite only reached 2.83 to 8.62 or 2.69 to 5.84 in the range of 4GHz to 18GHz, respectively, and it was apparent that the dielectric loss effect was inferior to that of example 2 (. Epsilon."/ε' was 2.64 to 12.27).
TABLE 1 Fe obtained under different experimental conditions 2 O 3 Dielectric property (epsilon '/epsilon') corresponding relation table of N-doped nanosheet graphite of @ C (wherein the sample accounts for 50 percent, and paraffin wax is adopted50％)
Figure GDA0002612332700000091
Comparative example 1
In the plasma arc discharge evaporation process, the consumed anode target material is a high-purity graphite rod with the diameter of 10mm, and the distance between the graphite cathode and the anode target material is 1.5mm. The cavity is vacuumized to 5 multiplied by 10 -3 And (2) introducing reaction gases of argon 10kPa and acetonitrile 30ml into the vacuum cavity after Pa, switching on a direct current power supply, adjusting the voltage to be 24V-28V, generating arc discharge between the anode target material and the cathode to generate arc discharge current 60A, adjusting the working current and keeping the voltage relatively stable in the arc discharge process, and keeping the arc for 48 minutes. After the reaction gas is pumped out, the powdered common N-doped graphite is collected on the inner wall of the vacuum cavity.
Comparative example 2
Zhou Yuanliang et al also introduced H by plasma arc method with graphite rods as cathodes and anodes 2 (15KPa)/N 2 (10 KPa)/Ar (15 KPa) is used as an arc starting gas and a nitrogen source, and finally the nitrogen-doped two-dimensional nano graphite sheet structure with the N doping amount of 4.6at.% is obtained. However, the dielectric dissipation factor, i.e., the ratio of the imaginary part ε "(loss) of the dielectric constant to the real part ε' (stored energy) of the dielectric constant, is only 0.28-0.46 at 2-18 GHz. The nitrogen-doped nano-sheet graphite structure prepared by the method has a dielectric loss factor of more than 1 and a dielectric loss capacity far greater than that of the work.
Comparative example 3
Nan Zhou et al synthesized nano-Fe-loaded by a simple hydrothermal method 2 O 3 A particulate N-doped nanosheet graphite structure comprising graphite, potassium permanganate, sodium nitrate, sulfuric acid, hydrogen peroxide, urea, ethanol, and FeSO 4 ·7H 2 O and the like. The dielectric dissipation factor, i.e. the imaginary part ε ″ (loss) and permittivityThe ratio of real parts of electric constants epsilon' (stored energy) is only about 0.2-0.5 within 2-18GHz, which is far less than the invention (can reach 2.64-12.27).
The above embodiments are only for illustrating the technical idea and features of the present invention, and the purpose of the present invention is to enable those skilled in the art to understand the content of the present invention and implement the present invention, and not to limit the protection scope of the present invention by this means. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims (7)

1. Preparation of nitrogen-doped nano-sheet graphite structure or loaded Fe 2 O 3 A method of nitrogen doping of nano-particles into a nano-sheet graphite structure, characterized by: the high-temperature plasma arc evaporation technology is adopted for preparation, a high-purity graphite rod is used as a cathode, the high-purity graphite rod or a mixed block of high-purity Fe powder and high-purity graphite powder is used as an anode, after the electric arc furnace is vacuumized, no other reaction gas is needed to be filled, only liquid acetonitrile is introduced, the liquid acetonitrile enters a vacuum cavity and is used as a carbon source and a nitrogen source, and after plasma arc discharge is finished, sediment on the inner wall of the reaction cavity is collected to obtain the high-temperature plasma arc evaporation material;
wherein: the distance between the cathode and the anode target material is kept between 1mm and 5 mm; the vacuum degree of the electric arc furnace is better than 8 multiplied by 10 -3 Pa; the current of arc discharge is 60A-400A, and the voltage is 17V-100V; the electric arc holding time is 5min-120min, and the liquid acetonitrile filling amount is 5ml-60ml;
the cathode is of a bar body structure of ϕ mm- ϕ mm, one end, close to the anode, of a cathode graphite rod is conical, and the anode is of a bar body structure of ϕ mm- ϕ mm.
2. Preparation of nitrogen-doped nanosheet graphite structure or supported Fe as claimed in claim 1 2 O 3 A method of nitrogen doping of nano-particles into a nano-sheet graphite structure, characterized by: the percentage content of nitrogen-doped atoms in the obtained product is 2.16 at-5.84 at.%.
3. Preparation of nitrogen-doped nanosheet graphite structure or supported Fe as claimed in claim 1 2 O 3 A method of nitrogen doping of nano-particles into a nano-sheet graphite structure, characterized by: the amount of acetonitrile used was 30ml.
4. Preparation of nitrogen-doped nanosheet graphite structure or supported Fe as claimed in claim 1 2 O 3 A method of nitrogen doping of nano-particles into a nano-sheet graphite structure, characterized by: the purity of the high-purity graphite rod or the high-purity graphite powder is more than or equal to 99.9wt%, and the purity of the high-purity Fe powder is more than or equal to 99.9wt%.
5. Preparation of nitrogen-doped nanosheet graphite structure or supported Fe as claimed in claim 1 2 O 3 A method of nitrogen doping of nano-particles into a nano-sheet graphite structure, characterized by: when the anode target material is a mixed block of high-purity Fe powder and high-purity graphite powder, the contents of the two are as follows: 1at.% to 10at.% of high-purity Fe powder, and 90at.% to 99at.% of high-purity graphite powder.
6. Nitrogen-doped nano-sheet graphite structure or Fe-loaded nano-sheet graphite prepared by adopting method of any one of claims 1 to 5 2 O 3 Nanoparticle nitrogen-doped nanosheet graphite, characterized by: in the range of 2GHz-18GHz, the ratio of the imaginary part epsilon 'of the dielectric constant to the real part epsilon' of the dielectric constant of the nitrogen-doped nano-sheet graphite structure is more than 1, and the graphite structure is loaded with Fe 2 O 3 The ratio of the imaginary part epsilon 'of the dielectric constant of the nitrogen-doped nano-sheet layer graphite to the real part epsilon' of the dielectric constant of the nano-particles can reach 2.64-12.27.
7. The nitrogen-doped nano-sheet graphite structure or Fe-supported nano-sheet graphite structure of claim 6 2 O 3 The nitrogen-doped nano-sheet graphite of the nano-particles is applied as a wave-absorbing material of a frequency band between 4GHz and 18GHz at room temperature.
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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108793126A (en) * 2018-06-05 2018-11-13 华南理工大学 A kind of pyridine N doping porous graphene that defect is controllable and preparation and application
CN109970047A (en) * 2019-03-27 2019-07-05 昆明理工大学 A method of graphene quantum dot is prepared by carbon nanohorn

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103276486B (en) * 2004-11-09 2017-12-15 得克萨斯大学体系董事会 The manufacture and application of nano-fibre yams, band and plate
DE102009019747A1 (en) * 2009-05-02 2010-11-04 Bayer Technology Services Gmbh Process for the preparation of carbon materials with nitrogen modification starting from carbon nanotubes
TWI676593B (en) * 2018-04-26 2019-11-11 國立交通大學 Graphite Composite Conductive Bar Material And Method For Producing Graphene Using The Same

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108793126A (en) * 2018-06-05 2018-11-13 华南理工大学 A kind of pyridine N doping porous graphene that defect is controllable and preparation and application
CN109970047A (en) * 2019-03-27 2019-07-05 昆明理工大学 A method of graphene quantum dot is prepared by carbon nanohorn

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Submerged liquid plasma - low energy synthesis of nitrogen-doped graphene for electrochemical applications;Senthilnathan, J.等;《JOURNAL OF MATERIALS CHEMISTRY A》;20140102;第2卷(第10期);第3332-3337页 *
氮掺杂石墨烯制备方法综述;唐涛等;《广西物理》;20151231;第36卷(第1期);第27-31页 *

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