KR102265375B1 - Graphene powder doped with nitrogen with high concentration obtained using arc discharge, method for manufacturing the same and method for manufacturing graphene film - Google Patents

Abstract

The disclosed graphene powder is obtained by evaporating carbon rods filled therein with graphite powder and graphene oxide, the nitrogen content is 3 wt% or more, and the content of quaternary nitrogen-carbon bonds is 30% or more.

Description

Graphene powder doped with high concentration of nitrogen obtained by arc discharge, manufacturing method thereof, and manufacturing method of graphene film TECHNICAL FIELD FILM}

The present invention relates to graphene, and more particularly, to a graphene powder doped with high concentration of nitrogen obtained by arc discharge, a manufacturing method thereof, and a manufacturing method of a graphene film.

Carbon with atomic symbol 6 has various allotropes. As carbon atoms are arranged in a hexagonal structure, fullerene having a 0-dimensional structure in the shape of a bucky ball, carbon nanotube having a one-dimensional structure, graphene having a two-dimensional structure, three-dimensional structure There are carbon allotropes (allotropes) having various structures, such as graphite having a structure. Among them, graphene has a closed band gap, so it exhibits a fast electron mobility of about 200,000 cm/Vs, and has a conductivity 100 times higher than that of silicon and copper. In addition, it has a strength of about 1100 Gpa, 200 times higher than that of steel, and thermal conductivity of about 500 W/mK at room temperature is 10 times higher than that of diamond. It has great application potential in various fields using the excellent mechanical and electrical properties of graphene.

There are various methods for producing graphene, representatively there are mechanical methods, chemical vapor deposition (CVD) methods, chemical methods for producing graphene by oxidizing graphite, and also graphene using arc discharge method. There is a manufacturing method.

The mechanical method is to exfoliate graphite with Scotch tape, and the exfoliated graphene has a size of several hundred μm, and pure graphene can be obtained without damage, but mass production is difficult, and it is applied only to graphite way you can do it.

The CVD method decomposes into carbon and hydrogen components by flowing hydrocarbon gas at a high temperature. Among the decomposed components, carbon is a method of forming graphene by reacting with the surface of a specific metal substrate. Although graphene produced by this method has few defects, the growth rate or number of layers differs depending on the metal substrate, and in order to transfer graphene to the desired substrate, a process of removing the metal substrate is required.

The chemical method uses a _{strong oxidizing agent such as hydrogen peroxide (H 2} O ₂ ) and sulfuric acid (H ₂ SO ₄ ) to make graphite into oxidized graphene oxide, and then uses functional groups bonded to graphene oxide. groups), it is a method of obtaining graphene by removing functional groups by a thermal reduction method or a chemical reduction method using a reducing agent. The thermal reduction method is a method for reducing by removing functional groups of graphene oxide by performing high-temperature heat treatment in an atmosphere such as hydrogen (H2) or argon (Ar), and the chemical method using a reducing agent is hydrazine (N ₂ H ₄ ) and This is a method of obtaining graphene through a reduction reaction by adding the same reducing agent.

The graphene synthesis method using arc discharge is a method of producing graphene by applying a high current between an anode and a cathode to cause inversion to evaporate a graphite rod of the anode, and a buffer gas in a reaction chamber Pure graphene powder can be prepared by using various gases such as hydrogen (H2) and hydrogen/helium (H2/He), where the buffer gas is produced by CVD and chemical methods. A large amount of graphene can be produced within a considerably shorter time than the time. N-doped graphene doped with nitrogen can be prepared using not only pure graphene but also various dopants, which provide active sites or increase conductivity to provide catalysts, supercapacitors, gas sensors, biosensors, fuels, etc. It can be applied to batteries, etc. However, it was difficult to doping more than ~1% with the existing dopant technology that supplies nitrogen in gaseous form from the outside.

1. Chinese Laid-Open Patent Publication No. 101993060 (2011. 3. 30) 2. Chinese Laid-Open Patent Publication No. 101717083 (June 2, 2011) 3. Chinese Laid-Open Patent Publication No. 102153076 (2011. 8. 17) 4. Republic of Korea Patent Registration No. 10-1438027 (2014. 08. 29)

1. Nano Research, Youngsheng Chen, 2010, 3(9):661-669 2. Appl Phys A (Materials Science & Processing), L. Guan, 2011, 102: 289-294 3. J. Phys. Chem. C, C. N. R. Rao, 2009, No. 11: Vol. 113 4. Nanotechnology, 2014, 25, 445601

The technical problem of the present invention is to provide a highly concentrated nitrogen-doped graphene powder that can be doped with nitrogen at a high concentration and can impart high conductivity by having high crystallinity.

Another technical object of the present invention is to provide a method for producing the graphene powder.

Another technical object of the present invention is to provide a method for manufacturing a graphene film using the graphene powder.

Graphene powder according to an embodiment for realizing the object of the present invention is obtained by evaporating a carbon rod filled therein with a raw material including graphite powder and graphene oxide by arc discharge, and the nitrogen content is 3 weight % or more, and the content of quaternary nitrogen-carbon bonds is 30% or more.

The method of manufacturing graphene powder according to an embodiment of the present invention includes the step of evaporating the carbon rod by causing an arc discharge in a carbon rod connected to the anode in which a raw material is filled therein, and the raw material is graphite powder and oxidation containing graphene.

According to one embodiment, the weight ratio of the graphite powder and the graphene oxide in the raw material is 3:1 to 1:2.

According to an embodiment, the raw material further includes a nitrogen doping material.

According to one embodiment, the nitrogen doping material is polyaniline (PANi), 4-aminobenzoic acid (4-aminobenzoic acid (C ₇ H ₇ NO ₂ )), bismuth hydroxide nitrate oxide (bismuth hydroxide nitrate oxide (Bi ₅₎ O(OH) ₉ (NO ₃ ) ₄ )), phenylhydrazine hydrochloride (C ₆ H ₈ N ₂ HCl)), 4-dimethylaminopyridine (4- (dimethylamino)pyridine (C ₇ H ₁₀ N _{2 )} )), ammonium iodide (H ₄ IN)), polyacrylonitrile, iron(III) nitrate enneahydrate(Fe(NO ₃ ) _3● 9H ₂ O)), nickel nitrate Hexahydrate (nickel(II) nitrate hexahydrate(N ₂ NiO _6● 6H ₂ O)), 1,4-diamine benzene (C ₆ H ₄ (NH ₂ ) ₂ ) and ammonium molybdate It includes at least one selected from the group consisting of tetrahydrate (ammonium molybdate tetrahydrate((NH ₄ ) ₆ Mo ₇ O _24● 4H _{2 O)).}

According to an embodiment, the nitrogen doping material includes polyaniline.

According to an embodiment, the raw material includes 40 to 60% by weight of the graphite powder, 20 to 40% by weight of the graphene oxide, and 20 to 40% by weight of the nitrogen doping material.

According to one embodiment, the arc discharge is carried out in a reaction chamber.

According to an embodiment, the pressure in the reaction chamber is 200 to 600 torr, and in the reaction chamber, hydrogen (H ₂ ), nitrogen (N ₂ ), hydrogen/helium (H ₂ /He), hydrogen/nitrogen (H _{2 )} At least one buffer gas selected from the group consisting of /N ₂ ), hydrogen/argon (H ₂ /Ar), and hydrogen/helium/ammonia (H ₂ /He/NH _{3 ) is provided.}

According to an embodiment, the voltage applied between the anode and the cathode is 10 to 50V, and the current is 90 to 160A.

According to one embodiment, the nitrogen content of the graphene powder is 3% by weight or more, and the content of quaternary nitrogen-carbon bonds is 30% or more.

According to one embodiment, the method for producing the graphene powder further comprises the steps of removing amorphous carbon by heat-treating the graphene powder, and further comprising sonicating the graphene powder in an organic solvent. .

According to an embodiment, the organic solvent includes at least one selected from the group consisting of acetone, toluene, dimethylformamide and ethanol.

The method for producing a graphene film according to an embodiment of the present invention includes the steps of centrifuging the sonicated solution, collecting a supernatant of the centrifuged solution, and filtering the supernatant on a filter paper. includes

According to the present invention, it is possible to obtain a graphene powder doped with nitrogen at a high concentration and the content of quaternary nitrogen-carbon bonds is maximized. The graphene powder has few defects, high crystallinity and high conductivity. Therefore, it is possible to greatly improve the performance and usability of graphene. In addition, according to the present invention, since graphene can be produced in a short time by controlling the pressure condition of the arc discharge, it is advantageous for mass production.

1 is a flowchart illustrating a method of manufacturing graphene powder according to an embodiment of the present invention.
2 is a schematic cross-sectional view of an arc discharge device for producing graphene powder according to an embodiment of the present invention.
3 is a schematic diagram illustrating a carbon-nitrogen bond included in graphene.
4 is an SEM image and a TEM image of the graphene powder prepared according to Examples and Comparative Examples.
5 is a graph showing XPS results of graphene powders prepared according to Examples and Comparative Examples.
6A and 6B are graphs showing Raman spectroscopic analysis results of graphene powders prepared according to Examples and Comparative Examples.

In the present application, terms such as first and second may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It is to be understood that it does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

1 is a flowchart illustrating a method of manufacturing graphene powder according to an embodiment of the present invention. 2 is a schematic cross-sectional view of an arc discharge device for producing graphene powder according to an embodiment of the present invention.

Referring to FIG. 1, first, a raw material is filled in a carbon rod (S10). For example, the carbon rod may be a graphite rod made of graphite.

The carbon rod is not particularly limited as long as it has an internal space to be filled with a raw material. The inner space may have a hole shape extending along a longitudinal direction of the carbon rod. For example, the length of the carbon rod may be 10 to 50 cm, the outer diameter may be 1 to 20 mm, and the diameter of the inner hole may be 1 to 10 mm.

The raw material includes at least graphite powder and graphene oxide.

The graphite powder is not particularly limited as long as it is in the form of a graphite material.

The graphene oxide may be obtained by various methods. For example, the graphene oxide is obtained by oxidizing and exfoliating graphite with a strong acid (GO), reduced graphene oxide (rGO) obtained by reducing graphene oxide with a reducing agent, and mechanically exfoliating graphite Graphene oxide obtained by oxidizing graphene with an oxidizing agent may be included.

According to an embodiment of the present invention, by using graphite powder and graphene oxide as raw materials for arc discharge, the nitrogen content of the graphene powder can be greatly increased, and the content of quaternary nitrogen can be maximized. Accordingly, graphene powder having high crystallinity and high conductivity can be obtained.

According to an embodiment, a weight ratio of graphite powder and graphene oxide in the raw material may be 3:1 to 1:2. When the content of the graphene oxide is too small, the nitrogen doping content is lowered, and when it is excessive, the amorphous carbon increases and crystallinity may be reduced.

The raw material may further include a nitrogen doping material. The nitrogen doping material is not particularly limited as long as it can dope nitrogen into graphene, but preferably, it should be capable of binding to carbon constituting the hexagonal structure of graphene. For example, the nitrogen doping material is polyaniline (PANi), 4-aminobenzoic acid (4-aminobenzoic acid (C ₇ H ₇ NO ₂ )), bismuth hydroxide nitrate oxide (Bi ₅ O) (OH) ₉ (NO ₃ ) ₄ )), phenylhydrazine hydrochloride (C ₆ H ₈ N ₂ HCl)), 4-dimethylaminopyridine (4- (dimethylamino)pyridine (C ₇ H ₁₀ N ₂ ) ), ammonium iodide(H ₄ IN)), polyacrylonitrile, iron(III) nitrate enneahydrate(Fe(NO ₃ ) _3● 9H ₂ O)), nickel nitrate hexa hydrates (nickel(II) nitrate hexahydrate(N ₂ NiO _6● 6H ₂ O)), 1,4-diamine benzene(C ₆ H ₄ (NH ₂ ) ₂ ) and ammonium molybdate tetra It may include one or more selected from the group consisting of hydrates (ammonium molybdate tetrahydrate((NH ₄ ) ₆ Mo ₇ O _24● 4H _{2 O)).}

According to an embodiment, the nitrogen doping material may include polyaniline. Polyaniline has high temperature stability and can be decomposed at the synthesis temperature of graphene. When the nitrogen doping material is decomposed at too low a temperature, it is difficult to obtain a desired nitrogen doping effect.

For example, the content of the nitrogen doping material may be 50 wt% or less of the total weight of the raw material. When the content of the nitrogen doping material is excessive, the content of quaternary nitrogen may decrease and the content of pyridinic N or pyrrolic N may increase.

According to an embodiment, the raw material may include 40 to 60% by weight of graphite powder, 20 to 40% by weight of graphene oxide, and 20 to 40% by weight of a nitrogen doping material.

The carbon rod filled with the raw material is coupled to the electrode, and arc discharge is generated (S20).

An arc discharge device may be used for arc discharge of the carbon rod. Referring to FIG. 2 , the arc discharge device includes a reaction chamber 60 , an anode 40 and a cathode 70 disposed in the reaction chamber 60 . For example, the carbon rod 30 may be coupled to the anode 40 . The arc discharge device may further include a first connection part 10 for injecting and discharging a buffer gas into the reaction chamber 60 and a second connection part 20 for injecting and discharging cooling water. In addition, a motor 50 for rotating the carbon rod 30 may be coupled to the anode 40 .

For example, the buffer gas injected into the reaction chamber 60 is not particularly limited, but hydrogen (H ₂ ), nitrogen (N ₂ ), hydrogen/helium (H ₂ /He), hydrogen/nitrogen (H _{2 )} /N ₂ ), hydrogen/argon (H ₂ /Ar), and hydrogen/helium/ammonia (H ₂ /He/NH ₃ ) may be one or more selected from the group consisting of.

For example, the voltage applied between the anode 40 and the cathode 70 may be 10 to 50V, and the current may be 90 to 160A. In addition, the pressure in the reaction chamber 60 may be 200 to 600 torr. According to an embodiment, the voltage applied between the anode 40 and the cathode 70 may be 30V, the current may be 150A, and the pressure in the reaction chamber 60 may be 550torr.

When the pressure in the reaction chamber 60 increases, the arc discharge temperature increases, so that high-quality arc graphene can be manufactured. However, when the pressure is excessively high, the quality of graphene may be deteriorated because amorphous carbon and impurities are generated.

When the carbon rod 30 is coupled to the anode 40 and a high current is applied between the anode 40 and the cathode 70 to generate a discharge, electrons protruding from the cathode 70 are transferred to the anode 40 It collides with the carbon rod 30 coupled to the carbon rod 40 and evaporates. The evaporated materials move to a lower temperature and recombine, and in this process, carbon is deposited on the surface to form graphene. In this case, nitrogen doping may be performed by nitrogen-carbon bonding.

When the nitrogen (N) is bonded to carbon, it may have three types of bonding structures. For example, as shown in FIG. 3 , there are quaternary, pyridinic and pyrrolic forms in the bonding structure of carbon and nitrogen. Among them, a nitrogen-doped quaternary structure among three benzene ring structures in which carbon is a hexagonal structure is As more is formed, graphene with fewer defects or improved electrical conductivity can be obtained.

According to embodiments of the present invention, it is possible to obtain a graphene powder doped with nitrogen at a high concentration, and the content of quaternary nitrogen-carbon bonds is maximized. The graphene powder has few defects, high crystallinity and high conductivity. Therefore, it is possible to greatly improve the performance and usability of graphene. In addition, according to the present invention, since graphene can be produced in a short time by controlling the pressure condition of the arc discharge, it is advantageous for mass production.

For example, the nitrogen content of the graphene powder may be 3% by weight or more, and the content of quaternary nitrogen-carbon bonds may be 30% or more. For example, the nitrogen content of the graphene powder may be 3% to 10% by weight, and the content of quaternary nitrogen-carbon bonds may be 30% to 50%.

When the graphene powder is used as a supercapacitor electrode, it can have a much higher charge per unit area of ^{63 μFcm -2 than currently available materials.} The graphene powder may be applied to the manufacture of capacitors, catalysts, gas sensors, biosensors, fuel cells, and the like.

The method for producing graphene may further include an additional processing step for improving the performance of the graphene powder, or may be used in a method for producing a graphene film using the graphene powder.

The method of manufacturing graphene according to an embodiment may further include thermally refining the graphene. The thermal refining step has an effect of removing impurities included as by-products in the production of graphene.

In the thermal purification step, it is preferable to purify the prepared graphene within a temperature range of 380 to 450° C. for 20 to 90 minutes. When the temperature range is maintained below 380°C in the thermal refining step, there is a problem in that amorphous carbon cannot be completely removed, and when maintained above 450°C, not only amorphous carbon but also graphene can be removed.

The method of manufacturing graphene according to an embodiment may further include annealing the graphene. The annealing step may have the effect of removing impurities included as by-products in the production of graphene, and supplementing the graphene produced with a hexagonal structure.

The annealing step is preferably performed on the prepared graphene in an inert gas and a mixed gas atmosphere.

The temperature at which the annealing is performed in the annealing step is preferably in the range of 800 to 1,000° C., for example, may be annealed for 2 to 12 hours. When the annealing temperature is excessively low, it is difficult to convert the defects of graphene into a hexagonal structure, and when the annealing temperature is excessively high, energy may be excessively consumed or the graphene structure may be changed to a graphite structure.

In addition, the annealing is performed in an inert gas and mixed gas atmosphere, and the inert gas and mixed gas are selected from the group consisting of argon, argon/hydrogen, argon/nitrogen, ammonia, argon/ammonia, helium and helium/hydrogen. There may be more than one.

The method of manufacturing graphene according to an embodiment may further include ultrasonically treating the graphene.

The ultrasonication step is a process of preparing a dispersion solution by dispersing the prepared graphene in an organic solvent, and treating the dispersion solution with ultrasonic waves. The organic solvent is not limited as long as it can prepare a dispersion solution when the prepared graphene is added, but it is preferable that the prepared graphene is contained in an amount of 0.01 to 0.1 parts by weight based on 100 parts by weight of the organic solvent. . When the content of graphene included in the organic solvent is excessive, agglomeration may occur, and when too small, conductivity may be reduced.

For example, the organic solvent may be at least one selected from the group consisting of acetone, toluene, dimethylformamide and ethanol.

For example, the ultrasonic treatment time may be between 20 seconds and 5 hours. The graphene is uniformly dispersed through the ultrasonic treatment to form an excellent network between the dispersed graphenes, so that the finally manufactured graphene may have high conductivity. However, if the ultrasonic treatment time is excessively long, defects may be formed in the graphene.

The method for producing a graphene film according to an embodiment may include centrifuging the sonicated graphene dispersion solution and filtering the supernatant of the centrifuged dispersion solution on a filter paper to form a graphene film. have.

A filtering operation is required to produce a graphene film from a graphene dispersion solution, and in order to facilitate the filtering operation, the filter paper preferably has a pore size in an appropriate range. In addition, it is preferable that the material of the filter paper can be used as a support substrate of the graphene film.

For example, the pore size of the filter paper may be 0.1 to 0.3 μm, and the material of the filter paper may be one or more selected from the group consisting of PVDF (polyvinylidenedifluoride), PTFE (polytetrafluoroethylene) and AAO (anodic aluminum oxide).

Hereinafter, specific examples of the present invention will be described in more detail through specific examples.

Examples and Comparative Examples

Fill the raw material by mixing graphite (99.9%, KOJUNDO, powder size 50μm), graphene oxide (GO), and polyaniline (PANi) in the following weight ratio on an empty 6mm diameter carbon rod (10DC305, DAEHAN CARBON) and arc discharge was performed to prepare graphene.

Comparative Example 1: NAG1: (Graphite/GO/PANi = 1/0/0),

Example 1: NAG2: (Graphite/GO/PANi = 1/1/0),

Example 2: NAG3: (Graphite/GO/PANi = 2/1/1)

The arc discharge was performed at a voltage of 30V and a current of 150A, and as a buffer gas, a hydrogen / helium mixed gas was flowed at 100:400 sccm and NH ₃ gas at 400 sccm into the reaction chamber while maintaining the chamber pressure while maintaining 550 torr through arc discharge. Graphene powder was prepared.

4 is an SEM image and a TEM image of the graphene powder prepared according to Examples and Comparative Examples. (a), (b), (c) are SEM images of Comparative Example 1, Example 1 and Example 2, respectively, (d), (e), (f) are Comparative Example 1, Example 1 and Example 2, respectively TEM image of Example 2.

Referring to FIG. 4 , it can be seen that graphene powder was formed through arc discharge in Examples and Comparative Examples.

The graphene powder obtained according to Examples 1, 2 and Comparative Example 1 was heat-treated at 450° C. in air to remove amorphous carbon, dispersed by ultrasonication in an organic solvent (ethanol), and the graphite was submerged due to the density difference. The supernatant was collected and graphene was collected on filter paper to form a film.

5 is a graph showing XPS results of graphene powders prepared according to Examples and Comparative Examples. Table 1 below shows the nitrogen doping concentration and the nitrogen-carbon bonding structure content obtained by analyzing the XPS results.

Table 1

5 and Table 1, in the case of Comparative Example 1, the nitrogen concentration was 3% below, and 100% of pyrrolic N was obtained, but in Examples 1 and 2 in which graphene oxide was added as a raw material, It can be seen that the nitrogen concentration was greater than 3%, and the content of quaternary N exceeded 30%.

In addition, in the case of Example 2 in which a nitrogen doping material (polyaniline) was added, it can be confirmed that the nitrogen concentration was further increased.

6A and 6B are graphs showing Raman spectroscopic analysis results of graphene powders prepared according to Examples and Comparative Examples. Table 2 below shows the results of Raman spectroscopy.

Table 2

Referring to Figures 6a, 6b and Table 1, compared to graphite (Pristine Arc G), in the order of Example 2 > Example 1 > Comparative Example 1, the shift of G and 2D peaks was large, which is nitrogen doping It means that the internal strain increased by , and through this, it can be confirmed that high-concentration nitrogen doping was made uniformly.

Table 3 below shows the surface area change and nitrogen content change after the purification process of Comparative Examples 1 and 2. Referring to Table 3, according to the present invention, it can be confirmed that the increase in the surface area is larger and the decrease in the nitrogen content is small after the purification process, and through this, it can be seen that graphene having a small content of amorphous carbon is obtained.

Table 3

Although described above with reference to the embodiments, those skilled in the art can variously modify and change the present invention within the scope without departing from the spirit and scope of the present invention described in the claims below You will understand.

The present invention can be applied to the manufacture of energy materials, electronic materials, capacitors, catalysts, gas sensors, biosensors, fuel cells, and the like.

Claims (14)

delete Including the step of evaporating the carbon rod by causing an arc discharge to the carbon rod filled with the raw material inside and connected to the anode,
The raw material includes graphite powder and graphene oxide,
The weight ratio of the graphite powder and the graphene oxide in the raw material is 3:1 to 1:2,
The method for producing a graphene powder, characterized in that the nitrogen content of the graphene powder is 3% by weight or more, and the content of quaternary nitrogen-carbon bonds is 30% or more. delete The method of claim 2, wherein the raw material further comprises a nitrogen doping material. According to claim 4, wherein the nitrogen doping material is polyaniline (PANi), 4-aminobenzoic acid (4-aminobenzoic acid (C ₇ H ₇ NO ₂ )), bismuth hydroxide nitrate oxide (bismuth hydroxide nitrate oxide (Bi ₅₎ O(OH) ₉ (NO ₃ ) ₄ )), phenylhydrazine hydrochloride (C ₆ H ₈ N ₂ HCl)), 4-dimethylaminopyridine (4- (dimethylamino)pyridine (C ₇ H ₁₀ N _{2 )} )), ammonium iodide (H ₄ IN)), polyacrylonitrile, iron(III) nitrate enneahydrate(Fe(NO ₃ ) _3● 9H ₂ O)), nickel nitrate Hexahydrate (nickel(II) nitrate hexahydrate(N ₂ NiO _6● 6H ₂ O)), 1,4-diamine benzene (C ₆ H ₄ (NH ₂ ) ₂ ) and ammonium molybdate A method for producing graphene powder, comprising at least one selected from the group consisting of tetrahydrate (ammonium molybdate tetrahydrate ((NH ₄ ) ₆ Mo ₇ O _24● 4H _{2 O)).} The method of claim 5, wherein the nitrogen doping material comprises polyaniline. The graphene powder of claim 5, wherein the raw material comprises 40 to 60 wt% of the graphite powder, 20 to 40 wt% of the graphene oxide, and 20 to 40 wt% of the nitrogen doping material manufacturing method. The method of claim 2, wherein the arc discharge is performed in a reaction chamber. The method of claim 8, wherein the pressure in the reaction chamber is 200 to 600 torr, and in the reaction chamber, hydrogen (H ₂ ), nitrogen (N ₂ ), hydrogen/helium (H ₂ /He), hydrogen/nitrogen (H _{2 )} /N ₂ ), hydrogen / argon (H ₂ /Ar), hydrogen / helium / ammonia (H ₂ /He / NH ₃ ) Graphene powder, characterized in that provided with at least one buffer gas selected from the group consisting of manufacturing method. The method of claim 2, wherein the voltage applied between the anode and the cathode is 10 to 50V, and the current is 90 to 160A. delete 3. The method of claim 2,
removing the amorphous carbon by heat-treating the graphene powder; and
Method for producing graphene powder, characterized in that it further comprises the step of ultrasonically treating the graphene powder in an organic solvent. The method of claim 12, wherein the organic solvent comprises at least one selected from the group consisting of acetone, toluene, dimethylformamide and ethanol. centrifuging the sonicated solution of claim 12;
collecting a supernatant of the centrifuged solution; and
Method for producing a graphene film comprising the step of filtering the supernatant on a filter paper.

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