Discharge body with discharge surface coated with graphene as well as preparation method and application of discharge body

Abstract

The invention relates to the field of discharge body preparation, in particular to a discharge body with a discharge surface coated with graphene and a preparation method and application of the discharge body. The discharge surface of the discharge body is coated with graphene, so that the work function of the discharge body is reduced, electrons are easier to leave a discharge tip, the discharge current is increased, and the discharge is stronger; and through chemical vapor deposition and selection of a solid carbon source and a gas carbon source, a multi-layer, low-defect and continuously-covered thick graphene layer is formed on the discharge surface of the discharge body, so that the discharge body is stable in discharge current and relatively long in service life in the discharge process.

Description

Technical Field

[0001] The present invention relates to the field of discharge body preparation, and particularly relates to a discharge body with a graphene-coated discharge surface, a preparation method thereof, and an application thereof. Background Art

[0002] Gas discharge phenomena have a wide range of applications in many fields, such as electrostatic precipitation, air purification, ozone generation, static elimination, gas sensing, ion wind heat dissipation, etc. As a key component for generating gas discharge, the gas discharge body needs to work in various complex air environments. Due to the local high temperature, strong oxidizing molecules, free radicals, etc. generated at the tip of the gas discharge, the gas tip is easily eroded due to melting, volatilization, reaction, etc., thereby affecting the gas discharge efficiency and lifespan.

[0003] Currently, metals are mainly used as electrodes for gas discharge. However, when strong discharge is required, it is desired that the metal has a low work function (i.e., electrons are easily excited out of the electrode); when the electrode is required to be corrosion-resistant and have a long lifespan, it is desired that the metal has a high oxidation potential (i.e., the electrode is easy to obtain electrons rather than lose electrons). Usually, a functional layer is covered on the discharge surface of the electrode to improve the discharge performance of the discharge surface.

[0004] Since graphene was successfully isolated from graphite by physicists Andre Geim and Konstantin Novoselov at the University of Manchester in the UK in 2004, and it was confirmed that monolayer graphene can exist alone, researchers have developed many graphene preparation methods, such as mechanical exfoliation method, epitaxial growth method, chemical reduction method, chemical vapor deposition method, etc. Among them, chemical vapor deposition (CVD) is the best method for preparing large-area and high-quality graphene. Existing research has attempted to use graphene to cover the discharge surface of the metal discharge body to increase the current of the discharge surface of the discharge body and improve the lifespan of the discharge surface. However, it is difficult to prepare a graphene layer with excellent quality in the prior art, resulting in limited improvement in the performance of the discharge surface of the discharge body.

[0005] The discharge surface of the existing gas discharge body is easily corroded under strong discharge conditions, resulting in large fluctuations in the discharge current and a short lifespan of the discharge body. Summary of the Invention

[0006] The purpose of the present invention is to overcome the problem that the discharge surface of the gas discharge body in the prior art is easily corroded under strong discharge conditions, resulting in large fluctuations in the discharge current and a short lifespan of the discharge body, thereby providing a discharge body with a graphene-coated discharge surface, a preparation method thereof, and an application thereof.

[0007] The solution adopted by the present invention is as follows:

[0008] The present invention provides a method for preparing a discharge body with a graphene-coated discharge surface, comprising the following steps: depositing thick-layer graphene on the discharge surface of the discharge body by chemical vapor deposition, thereby obtaining a discharge body with a graphene-coated discharge surface, wherein the carbon source for depositing the thick-layer graphene includes a solid carbon source and a gas carbon source.

[0009] In the present application, thick-layer graphene refers to graphene with more than 10 layers.

[0010] Preferably, the number of graphene layers of the thick-layer graphene is 10 - 1200.

[0011] Preferably, the material of the discharge body is selected from pure metals and alloys;

[0012] Preferably, the material of the discharge body is selected from nickel, copper, cobalt, ruthenium, iridium, and platinum;

[0013] Preferably, the material of the discharge body is selected from Ni-Mo alloy and Cu-Ni alloy;

[0014] Preferably, the shape of the discharge body is rod-shaped, filamentous, needle-shaped, or irregular;

[0015] Preferably, the discharge surface of the discharge body is the end face or side wall of a rod-shaped material, the end face or side wall of a filamentous material, the tip end face of a needle-shaped material, or the convex surface of an irregular body.

[0016] Preferably, the radius of curvature of the tip of the needle-shaped material is less than 1000 μm; for example, 3 μm, 4 μm, 5 μm, 6 μm, 10 μm, 100 μm, 200 μm, 500 μm, 800 μm, or 1000 μm.

[0017] Preferably, the solid carbon source is selected from at least one of polystyrene, graphite, sucrose, glucose, polymethyl methacrylate, and phenolic resin;

[0018] Preferably, the solid carbon source is selected from graphite paper;

[0019] Preferably, the gas carbon source is selected from at least one of methane, acetylene, ethylene, benzene, and propane.

[0020] Preferably, the carrier gas in the chemical vapor deposition is selected from hydrogen and argon;

[0021] Preferably, the flow rate of hydrogen is 1 - 10 sccm;

[0022] Preferably, the flow rate of argon is 300 - 600 sccm.

[0023] Preferably, the temperature for chemical vapor deposition of thick-layer graphene is 1100 - 1200 °C; the time is 60 - 120 min.

[0024] Preferably, in chemical vapor deposition, at least one surface of the solid carbon source is in contact with the discharge body;

[0025] Preferably, the solid carbon source is graphite paper. In chemical vapor deposition, the discharge body is placed on the surface of the graphite paper, and the orthographic projection of the discharge surface of the discharge body on the surface of the graphite paper is within the range of the surface of the graphite paper;

[0026] More preferably, the solid carbon source is folded graphite paper. The folded graphite paper has two opposite folding parts, and a clamping space is formed between the folding parts. In chemical vapor deposition, the discharge body is placed in the clamping space, and the orthographic projection of the discharge surface of the discharge body on the folding part is within the range of the surface of the folding part.

[0027] Preferably, the gas flow of the gas carbon source flows in the direction towards the discharge surface of the discharge body;

[0028] Preferably, the gas carbon source is selected from methane, and the flow rate of methane is 2 - 4.5 sccm.

[0029] Preferably, the two opposite folding parts of the folded graphite paper are connected by a crease line;

[0030] Preferably, the discharge body is a needle-shaped material; the length direction of the needle-shaped material is parallel to the crease line.

[0031] Preferably, before depositing graphene on the discharge surface of the discharge body, a process of cleaning the discharge surface of the discharge body is further included;

[0032] Preferably, after cleaning the discharge surface of the discharge body and before depositing graphene, a process of annealing the discharge body is further included;

[0033] More preferably, the annealing temperature is 1100 - 1120 °C, and the annealing time is 10 - 30 min;

[0034] More preferably, during the annealing process, the flow rate of argon is 400 - 500 sccm, and the flow rate of hydrogen is 50 - 100 sccm.

[0035] Preferably, a cooling process is further included after depositing graphene;

[0036] More preferably, the cooling process is a process of natural cooling of the discharge surface of the discharge body with the deposition equipment after depositing graphene.

[0037] It can be understood that the cooling process is that after depositing graphene on the discharge surface of the discharge body, the power supply of the deposition equipment is cut off, ventilation is maintained, and the discharge body is allowed to cool naturally in the deposition equipment.

[0038] The present invention also provides a discharge body with a graphene-coated discharge surface, which is prepared by using the method described above.

[0039] The present invention also provides a discharge body with a graphene-coated discharge surface prepared by the method described above, or the application of the discharge body with a graphene-coated discharge surface in electrostatic dust removal, air purification, ozone generation, static electricity elimination, gas sensing, and ion wind heat dissipation.

[0040] Advantages of the present invention:

[0041] The present invention provides a method for preparing a discharge body with a graphene-coated discharge surface, including the following steps: depositing thick-layer graphene on the discharge surface of the discharge body by chemical vapor deposition to obtain the discharge body with a graphene-coated discharge surface, wherein the carbon source for depositing the thick-layer graphene includes a solid carbon source and a gas carbon source.

[0042] In the present invention, by coating graphene on the discharge surface of the discharge body, the work function of the discharge body is reduced, so that electrons are more likely to leave the discharge tip, the discharge current increases, and the discharge is stronger; and by chemical vapor deposition and selecting a solid carbon source and a gas carbon source, a thick-layer graphene layer with multiple layers, low defects, and continuous coverage is formed on the discharge surface of the discharge body, which can make the discharge current of the discharge body stable during the discharge process and the service life longer. Description of the drawings

[0043] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0044] Figure 1 Schematic diagram of the shape of the discharge body;

[0045] Figure 2 Schematic diagram of the process of coating graphene on the discharge surface of the discharge body;

[0046] Figure 3 Comparison diagram of the optical microscope images of the tip surfaces of the discharge bodies of Example 1, Comparative Example 1, and Comparative Example 2;

[0047] Figure 4 Comparison diagram of the scanning electron microscope images of the tip surfaces of the discharge bodies of Example 1, Comparative Example 1, and Comparative Example 2;

[0048] Figure 5 Comparison diagram of the Raman spectra of the tip surfaces of the discharge bodies of Example 1, Comparative Example 1, and Comparative Example 2;

[0049] Figure 6 Diagram for measuring the thickness and number of layers of the thick-layer graphene film of the discharge body prepared in Example 1

[0050] Figure 7 Discharge performance diagrams of the discharge bodies with graphene-coated discharge surfaces prepared in Example 1, Comparative Example 1, and Comparative Example 2;

[0051] Description of the drawings: 1 - Discharge body substrate; 2 - Discharge surface of the discharge body. Detailed implementation manners

[0052] The following embodiments are provided to better further understand the present invention. They are not limited to the described optimal implementation manner, and do not limit the content and protection scope of the present invention. Any product that is the same as or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with those of other existing technologies falls within the protection scope of the present invention.

[0053] For those embodiments where specific experimental steps or conditions are not indicated, the operations or conditions of the conventional experimental steps described in the literature in this field can be followed. For the reagents or instruments whose manufacturers are not indicated, they are all conventional reagent products that can be obtained through commercial purchase.

[0054] In the embodiments of the present application, the shape of the discharge body substrate 1 (as Figure 1 shown) is rod-shaped, filamentous, needle-shaped, or irregular; the discharge surface 2 of the discharge body is the end face or side wall of the rod-shaped material, the end face or side wall of the filamentous material, the tip end face of the needle-shaped material, or the convex surface of the irregular body.

[0055] In the embodiment of the present application, a nickel needle is used as the discharge body, which is a cylindrical shape with a diameter of 0.9 mm, and one end is needle-shaped, and the curvature at the tip of the needle is 6.0 μm;

[0056] The CVD tube furnace used in the embodiments and comparative examples of the present application is an electric furnace with the model KLG-12-3Y produced by Tianjin Kaiheng Electric Heating Technology Co., Ltd.

[0057] Example 1

[0058] This embodiment provides a preparation method for a discharge body with a graphene-coated discharge surface, which specifically includes the following steps:

[0059] S1: Ultrasonically clean the nickel needle with acetone for 30 min to remove surface dirt, then ultrasonically clean it with isopropanol for 30 min to remove the remaining acetone on the surface of the nickel needle, then ultrasonically clean it with ethanol for 30 min to remove the isopropanol on the surface of the nickel needle, then ultrasonically clean it with pure water for 30 min to remove the ethanol on the surface of the nickel needle, and finally blow the surface of the ultrasonically cleaned nickel needle with a high-airflow nitrogen gun to remove the remaining moisture on the surface of the nickel needle;

[0060] S2: Take the folded graphite paper. The folded graphite paper has two opposite folding parts, and a clamping space is formed between the folding parts. Place the nickel needle in the clamping space (the orthographic projection of the tip of the nickel needle on the folding parts is within the surface range of each folding part, and the length direction of the nickel needle is parallel to the crease line). Place the nickel needle and the folded graphite paper together above the quartz plate and gently and slowly feed them into the CVD tube furnace chamber;

[0061] S3: Use argon to clean the CVD tube furnace chamber (to remove air); then introduce argon (the flow rate is 500 sccm) and hydrogen (the flow rate is 100 sccm) and heat up to 1100 °C (the heating time is 150 min). After maintaining the temperature for 25 min, reduce the argon flow rate to 300 sccm, reduce the hydrogen flow rate to 1 sccm, and introduce methane (the flow rate is 4.5 sccm, and the methane gas flow flows along the direction towards the tip of the nickel needle) to grow graphene with a layer thickness at 1100 °C for 120 min (the schematic diagram of the process of covering the graphene on the discharge surface of the discharge body is as Figure 2 shown); after the growth is completed, slowly cool it in the furnace (cut off the power supply of the CVD tube furnace and keep the gas introduction state unchanged) to obtain a discharge body with a graphene-coated discharge surface.

[0062] Example 2

[0063] This example provides a method for preparing a discharge body with a graphene-coated discharge surface, which specifically includes the following steps:

[0064] S1: Ultrasonically clean the nickel needle with acetone for 30 min to remove surface dirt, then ultrasonically clean it with isopropanol for 30 min to remove the remaining acetone on the surface of the nickel needle, then ultrasonically clean it with ethanol for 30 min to remove the isopropanol on the surface of the nickel needle, then ultrasonically clean it with pure water for 30 min to remove the ethanol on the surface of the nickel needle, and finally blow the surface of the ultrasonically cleaned nickel needle with a high-airflow nitrogen gun to remove the remaining moisture on the surface of the nickel needle;

[0065] S2: Take the folded graphite paper. The folded graphite paper has two opposite folding parts, and a clamping space is formed between the folding parts. Place the nickel needle in the clamping space (the orthographic projection of the tip of the nickel needle on the folding parts is within the surface range of each folding part, and the length direction of the nickel needle is parallel to the crease line). Place the nickel needle and the folded graphite paper together above the quartz plate and gently and slowly feed them into the CVD tube furnace chamber;

[0066] S3: Clean the CVD tube furnace chamber with argon (to exclude air); then introduce argon (flow rate: 600 sccm) and hydrogen (flow rate: 50 sccm), heat up to 1200 °C (heating time: 150 min), after holding for 25 min, reduce the argon flow rate to 300 sccm, reduce the hydrogen flow rate to 10 sccm, and introduce methane (flow rate: 2 sccm, and the methane gas flow is in the direction towards the tip of the nickel needle) to grow graphene with a certain layer thickness at 1200 °C for 60 min; after the growth is completed, slowly cool it in the furnace (cut off the power supply of the CVD tube furnace and keep the gas introduction state unchanged) to obtain a discharge body with a graphene-coated discharge surface.

[0067] Example 3

[0068] This example provides a method for preparing a discharge body with a graphene-coated discharge surface, which specifically includes the following steps:

[0069] S1: Ultrasonically clean the nickel needle with acetone for 30 min to remove surface dirt, then ultrasonically clean it with isopropanol for 30 min to remove the remaining acetone on the surface of the nickel needle, then ultrasonically clean it with ethanol for 30 min to remove the isopropanol on the surface of the nickel needle, then ultrasonically clean it with pure water for 30 min to remove the ethanol on the surface of the nickel needle, and finally blow the surface of the ultrasonically cleaned nickel needle with a high-airflow nitrogen gun to remove the remaining moisture on the surface of the nickel needle;

[0070] S2: Take a folded graphite paper, where the folded graphite paper has two opposite folded parts, and a clamping space is formed between the folded parts. Place the nickel needle in the clamping space (the orthographic projection of the tip of the nickel needle on the folded parts is within the surface range of each folded part, and the length direction of the nickel needle is parallel to the crease line), and place the nickel needle and the folded graphite paper together above the quartz plate, and smoothly and slowly feed them into the CVD tube furnace chamber;

[0071] S3: Clean the CVD tube furnace chamber with argon (to exclude air); then introduce argon (flow rate: 400 sccm) and hydrogen (flow rate: 100 sccm), heat up to 1150 °C (heating time: 150 min), after holding for 25 min, reduce the argon flow rate to 300 sccm, reduce the hydrogen flow rate to 1 sccm, and introduce methane (flow rate: 5 sccm, and the methane gas flow is in the direction towards the tip of the nickel needle) to grow graphene with a certain layer thickness at 1150 °C for 120 min; after the growth is completed, slowly cool it in the furnace (cut off the power supply of the CVD tube furnace and keep the gas introduction state unchanged) to obtain a discharge body with a graphene-coated discharge surface.

[0072] Comparative Example 1

[0073] This comparative example provides a method for preparing a discharge body with a graphene-coated discharge surface, which specifically includes the following steps:

[0074] S1: Ultrasonically clean the nickel needles with acetone for 30 min to remove surface dirt, then ultrasonically clean with isopropanol for 30 min to remove the remaining acetone on the nickel needle surface, then ultrasonically clean with ethanol for 30 min to remove the isopropanol on the nickel needle surface, then ultrasonically clean with pure water for 30 min to remove the ethanol on the nickel needle surface, and finally blow the surface of the nickel needles obtained after ultrasonic cleaning with a high-airflow nitrogen gun to remove the remaining moisture on the nickel needle surface;

[0075] S2: Place the nickel needles above the quartz plate and gently and slowly feed them into the CVD tube furnace chamber;

[0076] S3: Use argon to clean the CVD tube furnace chamber (to remove air); then introduce argon (flow rate: 500 sccm) and hydrogen (flow rate: 100 sccm), heat up to 1100 °C (heating time: 150 min), keep the temperature for 120 min, then reduce the argon flux to 300 sccm, reduce the hydrogen flow rate to 1 sccm, introduce pure gas methane 4.5 sccm, and grow graphene at 1100 °C for 120 min; after the growth is completed, slowly cool down with the furnace (cut off the power supply of the CVD tube furnace and keep the gas introduction state unchanged) to obtain a discharge body with a graphene-coated discharge surface.

[0077] Comparative Example 2

[0078] This comparative example provides a method for preparing a discharge body with a graphene-coated discharge surface, which specifically includes the following steps:

[0079] S1: Ultrasonically clean the nickel needles with acetone for 30 min to remove surface dirt, then ultrasonically clean with isopropanol for 30 min to remove the remaining acetone on the nickel needle surface, then ultrasonically clean with ethanol for 30 min to remove the isopropanol on the nickel needle surface, then ultrasonically clean with pure water for 30 min to remove the ethanol on the nickel needle surface, and finally blow the surface of the nickel needles obtained after ultrasonic cleaning with a high-airflow nitrogen gun to remove the remaining moisture on the nickel needle surface;

[0080] S2: Take a folded graphite paper. The folded graphite paper has two opposite folded parts, and a clamping space is formed between the folded parts. Place the nickel needles in the clamping space (the orthographic projection of the tip of the nickel needle on the folded parts is within the surface range of each folded part, and the length direction of the nickel needle is parallel to the crease line), place the nickel needles and the folded graphite paper together above the quartz plate, and gently and slowly feed them into the CVD tube furnace chamber;

[0081] S3: Clean the CVD tube furnace chamber with argon (to remove air); then introduce argon (flow rate: 500 sccm) and hydrogen (flow rate: 100 sccm), and heat up to 1100 °C (heating time: 150 min). After holding for 25 min, reduce the argon flow rate to 300 sccm and reduce the hydrogen flow rate to 1 sccm, and grow thick-layer graphene at 1100 °C for 120 min. After the growth is completed, slowly cool the furnace with the power off while keeping the gas flow unchanged to obtain a discharge body with a graphene-coated discharge surface.

[0082] Test Example

[0083] 1. Use optical microscopy, scanning electron microscopy, and Raman spectroscopy to analyze the discharge bodies with graphene-coated discharge surfaces prepared in Examples 1, 2, 3 and Comparative Examples 1, 2.

[0084] 1.1 Figure 3 In (a) is the optical microscope image of the tip surface of the discharge body in Example 1, (b) is the optical microscope image of the tip surface of the discharge body in Comparative Example 1, and (c) is the optical microscope image of the tip surface of the discharge body in Comparative Example 2. Figure 4 In (a) is the scanning electron microscope image of the tip surface of the discharge body in Example 1, (b) is the scanning electron microscope image of the tip surface of the discharge body in Comparative Example 1, and (c) is the scanning electron microscope image of the tip surface of the discharge body in Comparative Example 2.

[0085] It can be seen that the thick-layer graphene obtained by the technical solution of the present application can completely cover, while only using a solid carbon source cannot continuously cover the tip surface of the discharge body (island distribution); only using a gas carbon source will have a locally uncovered area at the tip surface of the tip (shown in the local enlarged view of (b)). Figure 3 In the local enlarged view of (b).

[0086] 1.2 Figure 5 In (a) is the Raman spectrum of the tip surface of the discharge body in Example 1, (b) is the Raman spectrum of the tip surface of the discharge body in Comparative Example 1, and (c) is the Raman spectrum of the tip surface of the discharge body in Comparative Example 2. It can be seen that the thick-layer graphene in Comparative Example 1 and Comparative Example 2 both have obvious D peaks (structures of amorphous carbon), indicating that there are a large number of defects in the thick-layer graphene.

[0087] 2. Layer number determination

[0088] As Figure 6 shown, it is the thickness of the thick-layer graphene film prepared by the inventive method of Example 1. The test method is to measure the film after etching the nickel of the discharge body and transferring the film to the surface of a silicon wafer. The result shows that the thickness of the graphene film is 300 nm, corresponding to about 900 layers of graphene.

[0089] 3. Discharge performance test

[0090] The test method is as follows: The discharge bodies with graphene-coated discharge surfaces prepared in Example 1 and Comparative Examples 1 and 2 are used as anodes, a stainless steel plate is used as the cathode, and a positive high-voltage power supply is adopted. The test environment is a normal atmospheric pressure environment at room temperature. The distance between the tip of the discharge body and the stainless steel plate anode is 15 mm, and the test voltage is 10 kV. The test results are as Figure 7 shown. The discharge body with the graphene-coated discharge surface prepared in Example 1 can still maintain good current stability after continuous discharge for 800 hours, while the discharge bodies with the graphene-coated discharge surfaces in Comparative Example 2 and Comparative Example 1 show a trend of current decay within 300 hours of discharge.

[0091] Obviously, the above examples are only given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or variations derived therefrom are still within the protection scope of the present invention.

Claims

1. A preparation method of a discharge body with a graphene-coated discharge surface, characterized in that, It includes the following steps: depositing a thick layer of graphene on the discharge surface of the discharge body by chemical vapor deposition, that is, obtaining a discharge body with a graphene-coated discharge surface, wherein the carbon sources for depositing the thick layer of graphene include solid carbon sources and gas carbon sources.

2. The preparation method according to claim 1, characterized in that, The number of layers of the thick-layer graphene is 10 - 1200.

3. The preparation method according to claim 1 or 2, characterized in that, The material of the discharge body is selected from pure metals and alloys; Preferably, the material of the discharge body is selected from nickel, copper, cobalt, ruthenium, iridium or platinum; Preferably, the material of the discharge body is selected from Ni-Mo alloy and Cu-Ni alloy; Preferably, the shape of the discharge body is rod-shaped, filamentous, needle-shaped or irregular; Preferably, the discharge surface of the discharge body is the end face or side wall of a rod-shaped material, the end face or side wall of a filamentous material, the tip end face of a needle-shaped material, or the convex surface of an irregular body; Preferably, the discharge surface of the discharge body is the tip end face of a needle-shaped material; Preferably, the radius of curvature of the tip of the needle-shaped material is less than 1000 μm; Preferably, the solid carbon source is selected from at least one of polystyrene, graphite, sucrose, glucose, polymethyl methacrylate, and phenolic resin; Preferably, the solid carbon source is selected from graphite paper; Preferably, the gas carbon source is selected from at least one of methane, acetylene, ethylene, benzene, and propane.

4. The preparation method according to any one of claims 1-3, characterized in that, The carrier gas in the chemical vapor deposition is selected from hydrogen and argon; Preferably, the flow rate of hydrogen introduced is 1 - 10 sccm; Preferably, the flow rate of argon introduced is 300 - 600 sccm.

5. The preparation method according to any one of claims 1-4, characterized in that, The temperature for chemical vapor deposition of the thick layer of graphene is 1100 - 1200 °C; the time is 60 - 120 min.

6. The preparation method according to any one of claims 1-5, characterized in that, In the chemical vapor deposition, at least one surface of the solid carbon source is in contact with the discharge body; Preferably, the solid carbon source is graphite paper. In the chemical vapor deposition, the discharge body is placed on the surface of the graphite paper, and the orthographic projection of the discharge surface of the discharge body on the surface of the graphite paper is within the range of the surface of the graphite paper; More preferably, the solid carbon source is folded graphite paper, the folded graphite paper has two opposite folding parts, a clamping space is formed between the folding parts, the discharge body is placed in the clamping space in the chemical phase deposition, and the orthographic projection of the discharge surface of the discharge body on the folding part is within the range of the surface of the folding part.

7. The preparation method according to any one of claims 1-6, characterized in that, The gas flow of the gas carbon source flows in the direction towards the discharge surface of the discharge body; Preferably, the gas carbon source is selected from methane, and the flow rate of methane introduced is 2 - 5 sccm.

8. The preparation method according to any one of claims 1-7, characterized in that, Before depositing graphene on the discharge surface of the discharge body, it further includes a process of cleaning the discharge surface of the discharge body; Preferably, after cleaning the discharge surface of the discharge body and before depositing graphene, it further includes a process of annealing the discharge body; More preferably, the annealing temperature is 1100 - 1120 °C, and the annealing time is 10 - 30 min; More preferably, during the annealing process, the flow rate of argon introduced is 300 - 600 sccm, and the flow rate of hydrogen introduced is 50 - 100 sccm.

9. A discharge body with a graphene-coated discharge surface, characterized in that, Prepared by the method according to any one of claims 1 - 8.

10. Application of the discharge body with a graphene-coated discharge surface prepared by the method according to any one of claims 1 - 8 or the discharge body with a graphene-coated discharge surface according to claim 9 in electrostatic dust removal, air purification, ozone generation, static elimination, gas sensing, and ion wind heat dissipation.

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