KR101159754B1 - Method of graphene synthesis via edge-functionalization of graphite - Google Patents

Abstract

The present invention is a method for producing graphene by the edge functionalization of graphite, the functionalized graphene having a functionalized organic material at the edge by preparing the organic material and graphite in the reaction medium containing the polymer phosphoric acid and a dehydrating agent, and then Functionalized graphene can be dispersed, centrifuged and reduced in a solvent, in particular heat treated, to obtain high purity, large area graphene and films. According to the present invention, graphene can be produced in large quantities at low cost while minimizing damage to graphite.

Description

Graphene synthesis by graphene edge functionalization {Method of graphene synthesis via edge-functionalization of graphite}

The present invention relates to a method for producing graphene by the edge functionalization of graphite, and more particularly, the edge position is functionalized by reacting graphite with organics in the presence of a weak acid, polyphosphoric acid (polyphosphoric acid). It relates to a method of producing pins, a method of obtaining graphene using the same, and a graphene obtained by such a method.

In general, graphite (graphite) is a material having a representative layered structure, a structure in which two-dimensional graphene (plateene) of plate-shaped carbon atoms connected in a hexagonal shape is laminated. Graphene is a representative single plate sheet composed of three carbon atoms bonded by SP ² hybrid orbital bonds, and is integrated in a hexagonal crystal lattice.

In graphite, the bond between carbon atoms in each layer of graphene is very strong as a covalent bond, but the bond between graphene and graphene is very weak compared to the covalent bond described above as a van der Waals bond.

Graphene refers to a single layer of graphite, that is, the (0001) plane monolayer of graphite, which has a very thin two-dimensional structure with a thickness of about 4 angstroms since the bond between graphene and graphene is weak as described above. There may be pins.

These graphenes have found very useful properties that differ from conventional materials.

The most notable feature is that when electrons move in graphene, the mass flows as if the mass of the electrons is zero, which means that the electrons flow at the speed of light travel in vacuum, that is, at the speed of light. In addition, such graphene is characterized by having an abnormal half-integer quantum hall effect on electrons and holes.

In addition, the electron mobility of the graphene is known to have a high value of about 20,000 to 50,000 cm 2 / Vs. Above all, in the case of carbon nanotubes similar to the graphene, since the yield is very low after the synthesis after purification, the final product is expensive even if synthesized using a cheap material, but graphite is very cheap. In the case of single-walled carbon nanotubes, not only the metal and semiconductor properties vary depending on the chirality and diameter, but also the band gaps are different even if they have the same semiconductor properties. In order to use the metallic properties, it is necessary to separate each single-walled carbon nanotube, which is known to be very difficult.

On the other hand, in the case of graphene, the electrical characteristics change according to the crystal orientation of the graphene having a given thickness, so that the user can express the electrical characteristics in the selection direction, so that the device can be easily designed. The characteristics of such graphene can be used very effectively in the future carbon-based electrical devices or carbon-based electromagnetic devices.

Due to such excellent characteristics of graphene, it is attracting attention as a material to replace the car wash silicon and ITO (INDIUM TIN OXIDE) transparent electrode.

Therefore, various methods for obtaining graphene have been continuously reported since 2004, which are mainly mechanical peeling, chemical peeling, SiC crystal pyrolysis, peel-reinsertion-expansion, chemical vapor deposition and epitaxy synthesis. Etc.

The mechanical peeling method uses the adhesion of the Scotch tape. When the cellophane tape is attached to the graphite sample and then the cellophane tape is peeled off, the graphene separated from the graphite adheres to the surface of the cellophane tape. However, in the case of such mechanical peeling method, the separated graphene is not always in the shape of torn paper, its size is only micrometer, so it is impossible to obtain a large area of graphene, and the final yield is extremely low. The problem is that many samples are low and not suitable for the required study.

Chemical exfoliation is a method of oxidizing graphite and crushing it with ultrasonic waves to form graphene oxide dispersed in an aqueous solution, and then reducing it back to graphene using a reducing agent such as hydrazine. However, since the oxidized graphene is not completely reduced and only about 70% is reduced, many defects remain in the graphene, thereby degrading excellent physical and electrical properties inherent to graphene.

SiC crystal pyrolysis is a method using the principle that when the SiC single crystal is heated, SiC on the surface is decomposed to remove Si and graphene is formed by the remaining carbon (C). However, in the case of such a pyrolysis method, there is a problem that SiC single crystal used as a starting material is very expensive, and it is very difficult to obtain graphene in a large area.

The exfoliation-reinsertion-expansion method involves inserting fuming sulfuric acid into graphite and placing it in a furnace at a very high temperature. As the sulfuric acid expands, the graphite expands by the gas and disperses it in a surfactant such as TBA, thereby making the graphene It is a method of manufacturing. The exfoliation-reinsertion-expansion also has a very low graphene yield, and due to the surfactants used, the interlayer contact resistance is large, thus failing to provide satisfactory electrical properties.

Chemical vapor deposition is a method of synthesizing graphene by using a transition metal that forms carbon and carbide alloys or adsorbs carbon well at a high temperature as a catalyst layer. This method is difficult to process, uses heavy metal catalysts, and there are many restrictions on mass production.

Epitaxy synthesis is based on the principle that carbon adsorbed or contained in crystals is grown to graphene along the surface of the substrate at high temperatures. The graphene prepared by this method has a relatively poor electrical property than graphene grown by mechanical peeling and chemical vapor deposition, and has a disadvantage in that the substrate is very expensive and the device is very difficult to manufacture.

In particular, with respect to the method for producing graphene using the above-described chemical vapor deposition method, there is a domestic registered patent No. 10-923304 "graphene sheet and its manufacturing method". This patent discloses a method for optimizing the CVD process among graphene manufacturing methods, but since the catalyst (graphitization catalyst) is used, a catalyst removal process by acid treatment is required, and the graphene manufacturing process is complicated. There is.

In addition, US Patent Publication No. 2010/0047154 "Method for producing graphene ribbon" is a method for producing a large amount of graphene ribbon, after cutting the finely chopped graphite, water is penetrated into the finely chopped graphite, water is infiltrated graphite It is disclosed a method for producing graphene after freezing and expanding. This publication discloses a method of physically cutting graphite and producing graphene using tensile stress due to volume expansion during freezing of water. In the production of graphene, an ultrasonic treatment process and a hydrophilic treatment process are disclosed. This is necessary, and there is a limitation that a piece of graphene in the form of a ribbon can be obtained, not a graphene sheet.

In order to solve various problems of the conventional graphene manufacturing method as described above, the present invention is a method for producing a graphene functionalized edge by reacting graphite with an organic material in the presence of a weak acid polymer phosphoric acid, by using the graphene It is an object to provide a method of obtaining and graphene obtained by this method.

An object of the present invention as described above, in the reaction medium containing a high molecular phosphoric acid and phosphorus pentoxide, the covalent bond between the graphene and the organic material to the bond of the edge position between the graphene forming the graphite by reacting the organic material and the graphite having a functional group And a functional group is one or more selected from the group consisting of a carboxylic acid group, an amide group, a sulfonic acid group, a carbonyl chloride group, and a carbonyl bromide group. Is achieved.

The organic material covalently bonded to the graphene acts as a wedge to peel off the graphene having the functionalized edge position in the graphite.

The organic substance is an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, and 3 to 3 carbon atoms except for the functional group. A cycloalkyl group having 10 members, an aryl group having 6 to 15 carbon atoms or an aralkyl group having 6 to 15 carbon atoms, and the alkyl group, alkenyl group, alkynyl group, cycloalkyl group, aryl group or aralkyl group Unsubstituted, halo, nitro, amino, cyano, mercapto, hydroxy, alkyl having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, formyl, alkylcarbonyl having 1 to 4 carbon atoms It is substituted with a substituent selected from the group consisting of, phenyl, benzoyl, phenoxy and combinations thereof.

Preferably, the organic material is unsubstituted, halo, nitro, amino, cyano, mercapto, hydroxy, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, formyl, 1 carbon Benzoic acid substituted with a substituent selected from the group consisting of 4 to 4 alkylcarbonyl, phenyl, benzoyl, phenoxy and combinations thereof.

More preferably, the organic material is 3-aminobenzoic acid, 4-aminobenzoic acid, 4- (4-aminophenyl) benzoic acid, 4- (3-aminophenyl) benzoic acid, 5-aminoisophthalic acid, 4- (4-amino Phenoxy) benzoic acid, 4- (3-aminophenoxy) benzoic acid, 3,4-diaminobenzoic acid, 3,5-diaminobenzoic acid, 2-phenoxybenzoic acid, 3-phenoxybenzoic acid, 4-phenoxybenzoic acid, 3,5-diphenoxybenzoic acid, 5-phenoxyisophthalic acid, 4-phenyl- (4-phenoxy benzoic acid), 4-phenoxy- (4-phenylbenzoic acid), 4-ethylbenzoic acid, 2-ethylbenzoic acid and 4 -Any one compound selected from the group consisting of ethylphenoxybenzoic acid.

The method for preparing the graphene functionalized with the edge position may further include dispersing the graphene functionalized with the edge position in a solvent and centrifuging to separate the graphene functionalized with the edge position from graphite. .

The solvent is water, methanol, ethanol, isopropyl alcohol, toluene, benzene, hexane, heptane, m-cresol, ethyl acetate, carbon disulfide, dimethyl sulfoxide, dichloromethane, dichlorobenzene, chloroform, carbon tetrachloride, acetone, tetrahydrofuran , Dimethylacetamide, N-methylpyrrolidone, dimethylformamide, acetic acid and mixtures thereof.

The centrifugation is carried out at a speed of 1,000 rpm to 15,000 rpm, preferably at a speed of 7,000 rpm to 12,000 rpm, for 30 seconds to 20 minutes, preferably for 2 to 15 minutes.

In addition, an object of the present invention, by reducing the edge position functionalized graphene obtained in accordance with the manufacturing method of the graphene functionalized edge position in the air or inert gas atmosphere, to remove the organic material functionalized the edge position It is achieved by the manufacturing method of graphene, including the one.

Preferably the reduction is heat treatment.

The heat treatment is performed for 30 minutes to 24 hours, preferably 2 hours to 6 hours at a temperature of 300 ℃ to 1,200 ℃, preferably 600 ℃ to 1000 ℃.

Graphene obtained by removing the organic material has a purity of 90% to 99%.

Graphene obtained by removing the organic material is composed of a single layer or a plurality of layers, and the thickness of the film is 0.3 nm to 1000 nm.

In addition, an object of the present invention is achieved by the graphene produced by the above-described manufacturing method, the film thickness is 0.3 nm to 1000 nm.

According to the present invention, in the reaction medium containing the polymer phosphoric acid and phosphorus pentoxide, by reacting the organic material having a variety of functional groups and graphite, the edge position of each graphene forming the graphite can be functionalized with the organic material, this organic material This wedge acts as an edge position functionalized graphene easily, and this edge position functionalized graphene is further processed (separation of edge functionalized graphene and removal of functionalized organics). The pins are easy to get.

In addition, the present invention can minimize the damage of the graphite and graphene by functionalizing the edge position of each graphene forming the graphite in the reaction medium of the polymer phosphoric acid / phosphorus pentoxide, which is milder than the conventional graphene manufacturing method as an organic material.

In addition, since the present invention satisfies the advantages of mass production of chemical exfoliation and high purity graphene of mechanical exfoliation at the same time, it is possible to mass produce graphene and to produce high purity graphene at low cost. have.

Therefore, the present invention is a method to further increase the application potential of graphene, and is widely used in various fields such as next-generation silicon, semiconductors, solar cell wafers, indium tin oxide (ITO) transparent electrodes, hydrogen storage bodies, optical fibers, and electrical devices. Can be utilized.

Figure 1 schematically shows a process for producing graphene according to the edge functionalization of graphite according to the present invention.
Figure 2 shows the manufacturing process of the graphene according to an embodiment of the present invention.
Figure 3 shows the experimental results for confirming the width, length and thickness of the graphene according to an embodiment of the present invention.
4 is a film photograph of a large-area graphene prepared on a quartz plate according to an embodiment of the present invention.

The present invention relates to a method for producing graphene, which is a high functional carbon material, in a simple and inexpensive mass, and to a graphene obtained by such a manufacturing method, and more particularly to graphene having functionalized edges by reacting graphite with an organic material. It relates to a method for producing, a method for obtaining graphene by removing the organic material on the graphene functionalized edges and a graphene obtained by the above methods. The present invention will be described in detail as follows.

In the method for producing a graphene functionalized at the edge position of the present invention, in the reaction medium containing the polymer phosphoric acid and phosphorus pentoxide, the graphene bonds the edge position between the graphenes forming the graphite by reacting graphite with an organic substance having a functional group. And a covalent bond between the organic substance and the organic substance, wherein the functional group is at least one selected from the group consisting of a carboxylic acid group, an amide group, a sulfonic acid group, a carbonyl chloride group, and a carbonyl bromide group.

The polymer phosphoric acid is a weak acid, the pH is 1 to 4, more preferably 2 to 3. The polymer phosphoric acid does not weaken the inherent properties of graphite because it functions as a weak acid but does not affect the original structure of the graphite. In addition, these polymer phosphates are easy to remove because they are soluble in water.

The phosphorus pentoxide is a dehydrating agent that removes water generated by the reaction of organic matter and phosphoric acid. Since phosphorus pentoxide reacts with water and is converted into polymer phosphoric acid, it has the advantage of being easy to remove because it does not affect other reactions and dissolves well in water except promoting the reaction of graphite and organic matter.

The reaction medium comprises the aforementioned polymeric phosphoric acid in an amount of 65% to 85% by weight, preferably in an amount of 74% to 83% by weight, and phosphorus pentoxide in an amount of 15% to 35% by weight, preferably Preferably in an amount from 17% to 26% by weight.

The functional group of the organic substance having the functional group is at least one selected from the group consisting of a carboxylic acid group, an amide group, a sulfonic acid group, a carbonyl chloride group and a carbonyl bromide group.

Preferably, the functional group of the organic material is at least one selected from the group consisting of -COOH, -CONH ₂ , -CONR'H, -CONR'R ", -SO ₃ H, -COCl and -COBr, wherein R 'And R' are each independently an alkyl group having 1 to 5 carbon atoms, an aryl group having 6 to 10 carbon atoms or an aralkyl group having 6 to 10 carbon atoms, and the alkyl group, aryl group or Aralkyl groups are unsubstituted, halo, nitro, amino, cyano, mercapto, hydroxy, alkyl having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, formyl, having 1 to 4 carbon atoms And substituted with a substituent selected from the group consisting of alkylcarbonyl, phenyl, benzoyl, phenoxy and combinations thereof.

The organic substance having the functional group may be an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, and a carbon atom, except for the functional group. A cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 15 carbon atoms or an aralkyl group having 6 to 15 carbon atoms, and the alkyl group, alkenyl group, alkynyl group, cycloalkyl group, aryl group, Or an aralkyl group is unsubstituted, halo, nitro, amino, cyano, mercapto, hydroxy, alkyl having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, formyl, 1 to 4 carbon atoms And substituted with a substituent selected from the group consisting of individual alkylcarbonyl, phenyl, benzoyl, phenoxy and combinations thereof.

Preferably, the organic material is unsubstituted, halo, nitro, amino, cyano, mercapto, hydroxy, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, formyl, 1 carbon Benzoic acid substituted with a substituent selected from the group consisting of 4 to 4 alkylcarbonyl, phenyl, benzoyl, phenoxy and combinations thereof.

More preferably, the organic material is 3-aminobenzoic acid, 4-aminobenzoic acid, 4- (4-aminophenyl) benzoic acid, 4- (3-aminophenyl) benzoic acid, 5-aminoisophthalic acid, 4- (4-amino Phenoxy) benzoic acid, 4- (3-aminophenoxy) benzoic acid, 3,4-diaminobenzoic acid, 3,5-diaminobenzoic acid, 2-phenoxybenzoic acid, 3-phenoxybenzoic acid, 4-phenoxybenzoic acid, 3,5-diphenoxybenzoic acid, 5-phenoxyisophthalic acid, 4-phenyl- (4-phenoxy benzoic acid), 4-phenoxy- (4-phenylbenzoic acid), 4-ethylbenzoic acid, 2-ethylbenzoic acid and 4 -Any one compound selected from the group consisting of ethylphenoxybenzoic acid.

In the reaction medium containing the polymeric phosphoric acid and phosphorus pentoxide, the organic material and the graphite are reacted in a weight ratio of 2: 1 to 1: 5, preferably in a weight ratio of 3: 2 to 1: 3.

At this time, the reaction temperature is 100 to 160 ℃, preferably 120 to 140 ℃, if the reaction temperature is less than 100 ℃ there is a problem that the reaction does not occur, if the reaction temperature exceeds 160 ℃ a lot of side reactions There is.

The reaction time is 12 hours to 120 hours, preferably 60 hours to 84 hours. When the reaction time is less than 12 hours, the reaction is not completed, and when the reaction time exceeds 120 hours, no further reaction proceeds.

0.01-40 parts by weight of graphite is added to 100 parts by weight of the reaction medium to carry out the reaction.

By the reaction of the organic material with the above-described graphite, graphene having an edge position functionalized with the organic material is produced. That is, in the reaction medium containing the polymer phosphoric acid and phosphorus pentoxide, the bond of the edge position between the graphene, which is each layer of the graphite to form the graphite by reacting the graphite with the organic substance, is replaced by the covalent bond between the functional group of the organic substance and the graphene edge carbon. Organic matter bound to the graphene of the graphite acts as a wedge serves to peel the graphene from the graphite.

1 shows an example of the reaction of the present invention as described above, in which the organic material having a functional group is reacted with graphite in a reaction medium including high molecular weight phosphoric acid and phosphorus pentoxide, and the graphene edge position of each layer of graphite is functionalized as an organic material. This wedge acts as a schematic representation of the separation of graphene.

FIG. 2 shows an example of the reaction of the present invention in more detail, showing a reaction of the present invention using p-aminobenzoic acid as an organic material having a functional group in a reaction medium containing polymer phosphoric acid and phosphorus pentoxide.

As such, when the organic material and the graphite are reacted in the reaction medium containing the polymer phosphoric acid and phosphorus pentoxide, the graphene functionalized at the edge is produced as described above, but the polymer product of the phosphoric acid and phosphorus pentoxide, including the graphite and the organic material which are not reacted in the reaction product, is This coexists.

In order to remove the polymeric phosphoric acid, phosphorus pentoxide, and unreacted organics from the reaction product in which various compounds coexist, the reaction product is washed with water, followed by washing with alcohol such as methanol. Thereafter, the washings may be dried using a method such as freeze drying.

When lyophilization is performed, the resulting edge position is dried while maintaining the space between the functionalized graphenes, and thus, when the lyophilisate obtained through the lyophilization is dissolved in the solvent again, the solvent is more likely to be functionalized between the graphenes. It can penetrate and, as a result, the functionalized graphene melts better, making the subsequent process easier.

In the freeze-dried product, since the unreacted graphite and the graphene functionalized at the edge are mixed, the dried material is dispersed in a solvent and centrifuged to separate the graphene functionalized at the edge.

The solvent depends on the type of organic matter bound to the edge position in graphene where the edge position is functionalized, such solvents being water, methanol, ethanol, isopropyl alcohol, toluene, benzene, hexane, heptane, m- Consisting of cresol, ethyl acetate, carbon disulfide, dimethyl sulfoxide, dichloromethane, dichlorobenzene, chloroform, carbon tetrachloride, acetone, tetrahydrofuran, dimethylacetamide, N-methylpyrrolidone, dimethylformamide, acetic acid and mixtures thereof It is selected from the group.

The centrifugation is performed at a speed of 1,000 rpm to 15,000 rpm, preferably at a speed of 7,000 rpm to 12,000 rpm, for 30 seconds to 20 minutes, and preferably for 2 to 15 minutes, so that the edge position is functionalized. To separate. If the centrifugation speed is less than 1,000 rpm, or if the centrifugation time is less than 30 seconds, the separation is not performed properly, and if the centrifugation speed exceeds 15,000 rpm or the centrifugation time exceeds 20 minutes, the centrifuge tube There is a risk of breaking.

The manufacturing method of the graphene of this invention includes reducing the graphene functionalized by the edge position obtained by the said method in air, an inert gas atmosphere, and removing the organic substance which functionalized the said edge position.

Nitrogen, argon, helium or neon gas may be used as the inert gas.

The reduction is performed by a method such as ultrasonic wave, plasma or heat treatment.

Reduction by heat treatment is preferred among the above reduction methods.

The heat treatment is performed for 30 minutes to 24 hours, preferably 2 hours to 6 hours at a temperature of 300 ℃ to 1,200 ℃, preferably 600 ℃ to 1,000 ℃. If the heat treatment temperature exceeds 1,200 ℃ or the treatment time exceeds 24 hours, there is a problem that the graphene is damaged, and if the heat treatment temperature is less than 300 ℃ or the treatment time is less than 30 minutes, it is difficult to remove the organic matter there is a problem.

Organic matter is removed from the graphene functionalized at the edge position by such a heat treatment, thereby obtaining pure graphene having a thickness of 0.3 to 1,000 nm.

Graphene obtained by removing the organic material has a purity of 90% to 99%, preferably 95 to 99%, more preferably 98% to 99%.

Graphene obtained by removing the organic material is composed of a single layer or a plurality of layers, and the thickness of the film is 0.3 nm to 1000 nm.

Hereinafter, the present invention will be described in detail with reference to examples, but these examples are only presented to more clearly understand the present invention, and are not intended to limit the scope of the present invention. It will be determined within the scope of the technical idea of the claims.

Example  1-1: Edge position is functionalized Graphene  Produce

Sigma-Aldrich Corporation polyphosphoric acid _{(115% H 3 PO 4 basis} ) is put into a high molecular acid (PPA) and phosphorus pentoxide (P ₂ O ₆₎ graphite 5g and amino acid 5g in the reaction medium 250g each containing 200g and 50g 130 The reaction was carried out at 72 ° C. for 72 hours to replace the edge positions of the graphenes with covalent bonds of carbon and aminobenzoic carbonyl groups at the edges of graphene to functionalize the edges of graphene.

Thereafter, the graphene having the functionalized edge position was precipitated in water, recovered again, and treated with Soxhlet for 3 days in water and methanol for 3 days, such as polymer phosphoric acid, phosphorus pentoxide and unreacted amino benzoic acid. Unreacted reaction was removed.

Thereafter, the lip-functionalized graphene, isolated from the non-reactants described above, was lyophilized.

Example  1-2: Edge position is functionalized Graphene  Produce

Sigma-Aldrich Corporation polyphosphoric acid _{(115% H 3 PO 4 basis} ) a polymeric acid (PPA) and phosphorus pentoxide (P ₂ O ₆₎ and the graphite 5g of 4- (2, 4 in the reaction medium, each containing 250g and 200g 50g 5 g of, 6-trimethylphenoxy) benzamide was added and reacted at 130 ° C. for 72 hours to form a bond between the edges of the graphene and carbon (4-, 2,4,6-trimethyl). The edge position of graphene was functionalized by substitution with a covalent bond to the carbonyl group of phenoxy) benzamide.

Thereafter, the edge-functionalized graphene was precipitated in water, recovered again, and treated with Soxhlet for 3 days in water and 3 days in methanol, to obtain high molecular weight phosphorus, phosphorus pentoxide and unreacted 4- (2 Unreacted materials, such as, 4,6-trimethylphenoxy) benzamide, were removed.

Thereafter, the lip-functionalized graphene, isolated from the non-reactants described above, was lyophilized.

Example  2: edge position is functionalized Graphene  detach

0.5 g of the freeze-dried product obtained according to Example 1-1 was dispersed in 500 ml of N-methylpyrrolidone solvent and stirred for 24 hours.

The dispersed lyophilisate was then centrifuged at 10,000 rpm for 10 minutes using a centrifuge to separate the graphene with the edge position functionalized from the lyophilisate. The graphene functionalized at the edge position thus obtained was 2 micrometers wide and 10 micrometers long.

In this regard, referring to Figure 3, the graph showing the width, length and thickness of the graphene, the width of the graphene peeled off using Atomic Force Microscope (AFM) is 2 micrometers, 10 micrometers or more in length It can be confirmed that, and only the edge of the molecular wedge-shaped functional group can be seen that.

Example  3: high purity Graphene  Produce

In order to obtain high purity graphene by removing the organic matter bound to the most position in the graphene functionalized in the edge position obtained in Example 2, heat treatment is performed.

That is, the edge position functionalized graphene is heat treated at 900 ° C. for about 1 hour to remove organic covalently bonded to the edge position of the graphene, thereby obtaining high purity graphene. The high purity of the graphene formed at this time is 98.3% and the thickness was 0.8 to 5 nm (see Fig. 3).

The present invention has been described above with reference to the illustrated examples, but this is only an example and the present invention can perform various modifications and other embodiments that are obvious to those skilled in the art. Understand the facts.

Claims (14)

As the manufacturing method of the graphene functionalized edge position,
In a reaction medium containing 65% to 85% by weight of polymeric phosphoric acid and 15% to 35% by weight of phosphorus pentoxide, organic matter having a functional group and graphite are reacted to show the binding of the edge positions between the graphenes forming the graphite. Wherein the functional group comprises at least one member selected from the group consisting of carboxylic acid groups, amide groups, sulfonic acid groups, carbonyl chloride groups, and carbonyl bromide groups. Method of preparing graphene. The method of claim 1, wherein the organic covalently bonded to the graphene acts as a wedge to release the graphene having a functionalized edge position from the graphite. According to claim 1, wherein the organic material is an alkyl group having 1 to 5 carbon atoms, Alkenyl group having 2 to 5 carbon atoms, Alkynyl group having 2 to 5 carbon atoms other than the functional group , A cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 15 carbon atoms, or an aralkyl group having 6 to 15 carbon atoms, and the alkyl group, alkenyl group, alkynyl group, cycloalkyl group, The aryl group or aralkyl group is unsubstituted, halo, nitro, amino, cyano, mercapto, hydroxy, alkyl having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, formyl, and carbon atoms 1 Preparation of edge-functionalized graphene, characterized in that substituted with a substituent selected from the group consisting of 4 to 4 alkylcarbonyl, phenyl, benzoyl, phenoxy and combinations thereof Law. The method of claim 1, wherein the organic material is unsubstituted, halo, nitro, amino, cyano, mercapto, hydroxy, alkyl having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, formyl, carbon atoms Method for producing a graphene functionalized edge position characterized in that the benzoic acid substituted with a substituent selected from the group consisting of 1 to 4 alkylcarbonyl, phenyl, benzoyl, phenoxy and combinations thereof. The method of claim 1, wherein the organic material is 3-aminobenzoic acid, 4-aminobenzoic acid, 4- (4-aminophenyl) benzoic acid, 4- (3-aminophenyl) benzoic acid, 5-aminoisophthalic acid, 4- (4- Aminophenoxy) benzoic acid, 4- (3-aminophenoxy) benzoic acid, 3,4-diaminobenzoic acid, 3,5-diaminobenzoic acid, 2-phenoxybenzoic acid, 3-phenoxybenzoic acid, 4-phenoxybenzoic acid , 3,5-diphenoxybenzoic acid, 5-phenoxyisophthalic acid, 4-phenyl- (4-phenoxy benzoic acid), 4-phenoxy- (4-phenylbenzoic acid), 4-ethylbenzoic acid, 2-ethylbenzoic acid and Method of producing a graphene functionalized edge position, characterized in that any one compound selected from the group consisting of 4-ethylphenoxybenzoic acid. The method of claim 1, further comprising dispersing the graphene functionalized at the edge position in a solvent and centrifuging to separate the graphene functionalized at the edge position from graphite. Way. The method of claim 6, wherein the solvent is water, methanol, ethanol, isopropyl alcohol, toluene, benzene, hexane, heptane, m-cresol, ethyl acetate, carbon disulfide, dimethyl sulfoxide, dichloromethane, dichlorobenzene, chloroform, carbon tetrachloride And acetone, tetrahydrofuran, dimethylacetamide, N-methylpyrrolidone, dimethylformamide, acetic acid, and mixtures thereof. The method of claim 6, wherein the centrifugation is performed at a speed of 1,000 rpm to 15,000 rpm for 30 seconds to 20 minutes. Preparing a graphene having an edge position functionalized by the method of claim 6;
Reducing the graphene in an air or inert gas atmosphere to remove the organic material functionalizing the edge position. The method of claim 9, wherein the reduction is heat treatment. The method of claim 10, wherein the heat treatment is performed at a temperature of 300 ° C. to 1,200 ° C. for 30 minutes to 24 hours. The method of claim 9, wherein the graphene obtained by removing the organic material has a purity of 90% to 99%. The method of claim 9, wherein the graphene obtained by removing the organic material is a single layer or a plurality of layers, and the thickness of the film is 0.3 nm to 1000 nm.
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