JP2019112237A - Graphene production method - Google Patents

Abstract

To provide a novel method for producing a relatively-low layer graphene that involves a reaction which can be completed at a relatively low temperature.SOLUTION: In the co-presence of a solvent, aluminum carbide is reacted with one kind or two or more kinds selected from carbon monoxide or a precursor thereof and carbon dioxide or a precursor thereof. Thus, the present invention has been perfected.

Description

  The present invention relates to a method of producing graphene.

Graphene has a two-dimensional structure composed of sp 2 carbon, and is called single-layer, two-layer, three-layer, multi-layer graphene or the like depending on the number of layers.

  Andre Geim and Konstantin Novoselov et al. Reported the physical properties of graphene separated by the exfoliation method in 2004, and measured their properties, and acquired the Nobel Prize in 2010 on the basis of their achievements. After that, various processes, physical properties, applications, etc. It has become explosively reported in the field.

  Besides the exfoliation method, various production methods such as a CO 2 reduction method, a SiC thermal decomposition method, graphene oxide, a chemical vapor deposition method (CVD), and the like have been studied.

  Chemical vapor deposition (CVD) is considered most promising as a method for producing large-area uniform graphene (Patent Document 1). However, heating up to 1000 ° C. or more is required, uniformity of the base copper surface is essential, and it has been difficult to say that this is a simple manufacturing method.

  The example which reduced CO2 by magnesium as a CO2 reduction method is disclosed (nonpatent literature 1). However, since the reaction proceeds explosively, it is difficult to control the reaction, and the obtained graphene is also 10 or more layers.

  On the other hand, there have also been some reports on aluminum carbide (Non-Patent Document 2, Non-Patent Document 3). However, it has an impression that it is difficult to use such as decomposition by water, oxygen, carbon monoxide and carbon dioxide, and the reaction is not completed due to the formation of an oxide film.

WO2011-25045

Journal of Materials Chemistry, 21, 9491-9493 (2011) Inorganic Materials, Vol. 4, 633-641 (1997) Journal of Applied Chemistry of the USSR, (36), 238-248 (1963)

  The problem to be solved by the present invention is to provide a novel method for producing relatively low-layer graphene which can be reacted at relatively low temperature.

  The present inventors came to complete the present invention as a result of earnest examination in order to solve the above-mentioned subject.

That is, the present invention includes the following aspects.
[1] A method for producing graphene, comprising reacting aluminum carbide with one or more selected from carbon monoxide or a precursor thereof and carbon dioxide or a precursor thereof in the presence of a solvent.
[2] The method for producing graphene according to claim 1, wherein the solvent is one or more selected from the group consisting of an organic solvent and an ionic liquid.
[3] The method for producing graphene according to claim 1 or 2, wherein the solvent is an organic solvent.
[4] The solvent is one or more selected from the group consisting of dimethylformamide, ethanol, acetonitrile, 2-propanol, methyl tert-butyl ether, tetrahydrofuran, dimethyl sulfoxide, and methanol. The manufacturing method of the graphene as described in any one of 1-3.
[5] The method for producing graphene according to any one of claims 1 to 4, wherein the solvent is one or more selected from the group consisting of dimethylformamide and ethanol.
[6] The method for producing graphene according to any one of claims 1 to 5, wherein the solvent is dimethylformamide.
[7] The method for producing graphene according to any one of claims 1 to 6, wherein the temperature of the reaction is −100 ° C. to 300 ° C.
[8] The method for producing graphene according to any one of claims 1 to 7, wherein the temperature of the reaction is −20 ° C. to 100 ° C.
[9] Graphene obtained by the method for producing graphene according to any one of claims 1 to 8.
[10] A product containing graphene according to claim 9.

 According to the method of the present invention, relatively low-layer graphene can be easily produced at a relatively low temperature (for example, around normal temperature and the like). In addition, the number of layers can be controlled by controlling the temperature and reaction of the CO 2 reduction method. In addition, it is significant that the use of a solvent makes it possible to separate graphene as a product from floating raw materials and by-products so as to be suspended or separated as a film.

It is a Raman spectrum measurement result of Example 1.

Hereinafter, the present invention will be described in detail.
The first aspect of the present invention is characterized in that aluminum carbide is reacted with one or more selected from carbon monoxide or a precursor thereof and carbon dioxide or a precursor thereof in the presence of a solvent. , A method of producing graphene.

  The aluminum carbide used in the present invention is not particularly limited as long as the reaction proceeds. For example, powders, granules, thin films, those generated in the system as a reactant, and the like can be mentioned. From the viewpoint of good solubility in a solvent, powdery ones generated in a system are preferable.

  As carbon monoxide or a precursor thereof (hereinafter abbreviated as carbon monoxide etc.) used in the present invention, carbon monoxide gas and those which can generate carbon monoxide by reaction in the system are particularly preferable. It is not limited. For example, metal carbonyl such as carbon monoxide gas; hexacarbonyl tungsten, hexacarbonyl molybdenum, octacarbonyl dicobalt, tetracarbonyl nickel, pentacarbonyl iron and the like; and the like can be mentioned. One or more of these may be used. Among these, carbon monoxide gas is preferable from the viewpoint of being a clean system that does not require removal of impurities and the like.

  The lower limit value of the concentration of carbon monoxide gas in the entire gas used in the present invention is not particularly limited as long as the reaction proceeds. From the viewpoint of smooth progress of the reaction, 300 ppb is preferable, 500 ppb is more preferable, 1 ppm is more preferable, 100 ppm is still more preferable, 0.01% is particularly preferable, and 1% is particularly preferable.

  The upper limit of the concentration of carbon monoxide gas in the entire gas used in the present invention is not particularly limited as long as the reaction proceeds. From the viewpoint of smooth progress of the reaction, 50% is preferable, 60% is more preferable, 70% is more preferable, 80% is still more preferable, 90% is particularly preferable, and 100% is particularly preferable.

  The carbon dioxide or a precursor thereof (hereinafter abbreviated as carbon dioxide etc.) used in the present invention is not particularly limited as long as it can generate carbon dioxide by carbon dioxide gas and a reaction in the system. For example, carbon dioxide gas; carbonates such as ammonium carbonate, lithium carbonate, sodium carbonate, potassium carbonate, calcium carbonate, barium carbonate, magnesium carbonate, iron carbonate, copper carbonate, silver carbonate, etc .; dimethyl carbonate, diethyl carbonate, ethylene carbonate, Carbonates such as propylene carbonate and diphenyl carbonate; and the like. One or more of these may be used. Among these, carbon dioxide gas and carbonate are preferable from the viewpoint that clean system or high quality graphene can be obtained without removing impurities and the like, carbon dioxide gas, dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, Diphenyl carbonate is more preferable, carbon dioxide gas, diethyl carbonate, ethylene carbonate and diphenyl carbonate are more preferable, diethyl carbonate and diphenyl carbonate are still more preferable, and diethyl carbonate and diphenyl carbonate are particularly preferable.

  The lower limit value of the concentration of carbon dioxide gas in the entire gas used in the present invention is not particularly limited as long as the reaction proceeds. From the viewpoint of smooth progress of the reaction, 400 ppm is preferable, 600 ppm is more preferable, 1000 ppm is more preferable, 10000 ppm is still more preferable, 0.1% is particularly preferable, and 1% is particularly preferable.

  The upper limit of the concentration of carbon dioxide gas in the entire gas used in the present invention is not particularly limited as long as the reaction proceeds. From the viewpoint of smooth progress of the reaction, 50% is preferable, 60% is more preferable, 70% is more preferable, 80% is still more preferable, 90% is particularly preferable, and 100% is particularly preferable.

The solvent used in the present invention is not particularly limited as long as the reaction proceeds, and those showing a liquid state under the conditions (pressure, temperature, etc.) to be used fall widely in this category. For example, alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol and t-butanol; ketones such as acetone and methyl ethyl ketone; ethers such as diethyl ether, methyl tertiary butyl ether, tetrahydrofuran and dioxane Alkanes such as pentane, hexane, heptane, octane, etc .; aromatic solvents such as benzene, toluene, xylene etc .; amide solvents such as dimethylformamide, dimethylacetamide etc .; acetonitrile; organic solvents such as dimethylsulfoxide; Ammonium, pyridinium, piperidinium, morpholinium, benzotriazolium, pyrazolium, pyrrolidinium, pyrrolinium, imidazolium, phosphonium, sulfonium, etc. And _{^{thione, AlCl 4 -, NO 2 -}} , NO 3 -, I -, BF 4 -, PF 6 -, AsF 6 -, SbF 6 -, NbF 6 -, TaF 6 -, F (HF) 2.3 -, p _{^{-CH 3 PhSO 3 -, CH 3}} CO 2 -, CF 3 CO 2 -, CH 3 SO 3 -, CF 3 SO 3 -, (CF 3 SO 2) 3 C -, C 3 F 7 CO 2 -, C ₄ F ₉ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) (CF ₃ CO ₂ ) N ⁻ , (CN) ₂ N ⁻ And the like, and an ionic liquid comprising; and the like. One or more of these may be used.
In addition, as a cation used for an ionic liquid, as long as it shows liquid state in combination with each anion, you may have multiple substituents.
In the case of using carbonate ester and water in combination, it is preferable to use equimolar or less equimolar water to carbonate ester in consideration of decomposability of aluminum carbide.

  The source of the solvent used in the present invention is not limited, and it may be added to the system separately, or may be one produced from the reaction, or one introduced from a separately added one.

  Among these, organic solvents and ionic liquids are preferable, and organic solvents are more preferable, from the viewpoint that the graphene to be formed may be a lower layer, and dimethylformamide, ethanol, acetonitrile, 2-propanol, methyl tertiary butyl ether, tetrahydrofuran, dimethylate are more preferable. Sulfoxide and methanol are more preferred, dimethylformamide, ethanol, acetonitrile, 2-propanol, methyl tertiary butyl ether, tetrahydrofuran and dimethyl sulfoxide are even more preferred, dimethylformamide, ethanol acetonitrile and 2-propanol are particularly preferred, and dimethylformamide is particularly preferred .

  It is considered that the difference in the layer state depending on the solvent type is due to the difference in the solvency of aluminum carbide or the difference in the structure upon solvation.

  The lower limit of the amount used for carbon monoxide and the like and / or aluminum carbide such as carbon dioxide used in the present invention is not particularly limited as long as the reaction proceeds. From the viewpoint of securing the reactivity in a predetermined time, 0.0001 molar equivalent is preferable, 0.001 molar equivalent is more preferable, 0.01 molar equivalent is more preferable, and 0.1 molar equivalent is still more preferable.

  The upper limit of the amount used for carbon monoxide and the like and / or aluminum carbide such as carbon dioxide used in the present invention is not particularly limited as long as the reaction proceeds. From the viewpoint of resource saving, 10000 molar equivalents are preferable, 1000 molar equivalents are more preferable, 100 molar equivalents is more preferable, 10 molar equivalents is still more preferable, 2 molar equivalents is particularly preferable, and 1 molar equivalent is particularly preferable.

The lower limit value of the concentration of the aluminum carbide used in the present invention to the solvent is not particularly limited as long as the reaction proceeds. From the viewpoint of easily forming a film, 1 × 10 ⁻²³ mass% is preferable, 0.0001 mass% is more preferable, 0.001 mass% is more preferable, 0.01 mass% is still more preferable, and 0.1 mass % Is particularly preferred.

  The upper limit value of the concentration of the aluminum carbide used in the present invention to the solvent is not particularly limited as long as the reaction proceeds. From the viewpoint of good separation of the raw material and the product, 99.999999 mass% is preferable, 70 mass% is more preferable, 50 mass% is more preferable, 30 mass% is still more preferable, 10 mass% is particularly preferable preferable.

  The lower limit value of the reaction temperature of the present invention is not particularly limited as long as the reaction proceeds. From the viewpoint of easy control of the time until completion of the reaction, -273 ° C is preferable, -100 ° C is more preferable, -40 ° C is more preferable, -20 ° C is still more preferable, 0 ° C is particularly preferable, and 10 ° C is particularly preferable preferable.

  The upper limit of the reaction temperature of the present invention is not particularly limited as long as the reaction proceeds. The time until reaction completion is easy to manage, it is preferably 1000 ° C., more preferably 500 ° C., still more preferably 300 ° C., still more preferably 200 ° C., particularly preferably 150 ° C., particularly preferably 100 ° C. preferable.

The lower limit value of the reaction pressure in the present invention is not particularly limited as long as the reaction proceeds. From the viewpoint of easy reaction management and efficient production, 1 × 10 ^-23 Pascal is preferable, 10 Pascal is more preferable, 100 Pascal is more preferable, and 1000 Pascal is still more preferable.

The upper limit of the reaction pressure in the present invention is not particularly limited as long as the reaction proceeds. From the viewpoint of easy reaction management and efficient production, 1 × 10 ²⁰ Pascals is preferable, 1 × ^{10 10} Pascals is more preferable, 1 × 10 ⁹ Pascals is more preferable, 1 × 10 ⁸ Pascals is further more preferable, and 1 × 10 ⁷ Pascals is particularly preferable.

The lower limit value of the reaction time of the present invention is not particularly limited as long as the reaction proceeds. From the viewpoint of productivity and easy reaction control, 1 hour is preferable, 1 minute is more preferable, 1 second is more preferable, 0.01 second is still more preferable, 0.0001 second is particularly preferable, 1 × 10 ^-23 seconds Is particularly preferred.

The upper limit of the reaction time of the present invention is not particularly limited as long as the reaction proceeds. From the viewpoint of productivity and easy reaction management, 1 × 10 ²⁰ hours is preferable, 200 hours is more preferable, 100 hours is further preferable, 10 hours is still more preferable, and 1 hour is particularly preferable.

  The reaction system of the present invention is not particularly limited as long as the reaction proceeds. For example, a fluid system, a stirring system, and a stationary system are mentioned. Among these, from the viewpoint of good film formability, the stirring method and the stationary method are preferable, and the stationary method is more preferable. From the viewpoint that reaction completeness is good due to contact between aluminum carbide raw materials, stirring blades, and vessel walls, the flow method and the stirring method are preferable, and the stirring method is more preferable. From the viewpoint of achieving both reaction completion and film formation, it is more preferable to use a flow method or a stirring method in which the speed is lowered to approach a stationary method.

  Various additives may be used in the system of the present invention as long as the reaction is not affected.

  In the system of the present invention, various films, metals and the like may be coexistent for the purpose of promoting crystal growth on the surface.

  Graphene obtained by the present invention is a racket, a shaft, a rod, a hammock, a speaker, and other such daily items; semiconductors such as transistors; batteries such as solar cells and thin film batteries; capacitors; conductive materials; composite materials; It can be used as a product of wiring, electronic parts of etc .; transportation equipment of automobile body, train body, aircraft body, ship hull etc., structures of bridges, buildings, dams, levees etc., etc.

  Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited by the examples.

〔Evaluation method〕
1. Layer number evaluation The product was measured by laser Raman spectrum using NAS-4100 manufactured by JASCO. The intensities of the D band (around 1340 cm-1), the G band (around 1580 cm-1), and the 2D band (around 2680 cm-1) were read and used as I _D , I _G , and I _{2 D} , respectively. Then, I _{2 D} / I _G was evaluated as ◎ at 1.1 or more, 未 満 at less than 1.1 at 1.0 or more, ○ at less than 1.0, and 0.5 or more at 、 0.5 0.5. In general, the ratio is considered to be a single layer in the vicinity of 2, two layers in the vicinity of 1, three layers in the vicinity of 0.5, and four layers or less in the vicinity of 0.5.
2. Evaluation of Crystallinity Degree In the same manner as above, I _D / (I _D + I _G + I _{2 D} ) is determined, ◎ less than 10%, で at 10% or more and less than 20% ○, Δ at 20% or more and less than 31%, 31% or more It was evaluated as ▲.
3. Evaluation of Reaction Completeness In the same manner as described above, the maximum peak intensity IA (860 cm −1) of the raw material aluminum carbide was obtained. In the case of I _A / (I _G + I _2D ), those less than 1 were evaluated as ○, and 1 or more as x.

Comparative Example 1
After nitrogen replacement in a glove box, 11.3 mg (78.5 μmol) of aluminum carbide is collected on a glass slide, lightly cured in a plastic case (100 mm x 60 mm x 25 mm) with a low sealing property, and put in a zippered plastic bag Closed. The plastic bag was taken out and transferred to a 10 L desiccator, and after carbon dioxide gas replacement three times, the zipper of the plastic bag was opened and carbon dioxide gas replacement was repeated again three times. Then, after standing for 115 hours at room temperature as a closed system of the desiccator, a solid substance was sampled and a laser Raman spectrum was measured. As a result, the aluminum carbide peak remained as a main peak and partially confirmed graphene formation.

[Example 1] Solvent examination After nitrogen substitution in a glove box, 100 mg (0.69 mmol) of aluminum carbide is collected in a container, and 246 mg (2.08 mmol, 3.0 molar equivalents vs. aluminum carbide) of diethyl carbonate and water 37 1 mL of dimethylformamide containing 5 mg (2.08 mmol, 3.0 molar equivalents vs. aluminum carbide) was sequentially added, a stir bar was added, and the Teflon seal was covered 3 times to cover. The container was taken out of the glove box and stirred with a magnetic stirrer at room temperature for 94 hours, and then the black suspension was sampled and the Raman spectrum was measured. As a result, generation of graphene without the coexistence of aluminum carbide peak could be confirmed.

[Examples 2 to 8]
In Example 1, dimethylformamide was changed to various solvents, reacted for each time, and the same operation was performed. The results are shown in Table 1.
From these results, particularly in the case of dimethylformamide, formation of single-layer graphene could be confirmed. In addition, even if other solvents were used, the completeness of reaction was high in all the houses, and formation of graphene having three or less layers was confirmed.

[Example 9]
After nitrogen substitution in a glove box, 100 mg (0.69 mmol) of aluminum carbide is collected in a container, and 246.3 mg (2.08 mmol, 3.0 molar equivalents vs. aluminum carbide) of diethyl carbonate and 37.5 mg of water (2. Add 1 mL of 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide containing 08 mmol, 3.0 molar equivalents vs. aluminum carbide), add a stir bar, cover the Teflon seal 3 times and cover Did. The container was taken out of the glove box and stirred with a magnetic stirrer for 89 hours at room temperature, and then the black suspension was sampled and the Raman spectrum was measured. As a result, it was possible to confirm the formation of graphene.
(I _2D / I _G = 1.01, I _D / (I _D + I _G + I _2D ) = 5%)

[Example 10]
After nitrogen substitution in a glove box, 9.9 mg (68.8 μmol) of aluminum carbide is collected in a container, and 444.6 mg (2.08 mmol, 30.2 molar equivalent vs. aluminum carbide) of diphenyl carbonate and 1 mL of dimethylformamide are sequentially obtained. The solution was added, a stirrer was added, and the Teflon seal was covered 3 times to cover. The vessel was removed from the glove box and stirred with a magnetic stirrer for 90 hours at room temperature. As a result of sampling and measurement of a Raman spectrum, generation of graphene could be confirmed.
(I _2D / I _G = 2.24, I _D / (I _D + I _G + I _2D ) = 7%)

[Example 11]
In a container from which 488.7 mg (1.39 mmol, 2.01 molar equivalents vs. aluminum carbide) of hexacarbonyl tungsten was collected, after replacing with nitrogen in a glove box, 100 mg (0.69 mmol) of aluminum carbide measured with a medicine sheet was placed, A solution of 171.2 mg of acetonitrile (4.17 mmol, 6.04 molar equivalent vs. aluminum carbide) in 1.0 ml of tetrahydrofuran was added and a stir bar was also added to cap. The vessel was removed from the glove box and magnetically stirred at room temperature for 91 hours. As a result of sampling and measurement of a Raman spectrum, generation of graphene could be confirmed.
(I _2D / I _G = 0.64, I _D / (I _D + I _G + I _2D ) = 19%)

Graphene obtained by the present invention is a racket, a shaft, a rod, a hammock, a speaker, and other such daily items; semiconductors such as transistors; batteries such as solar cells and thin film batteries; capacitors; conductive materials; composite materials; Electronic parts for wiring, etc .; Transportation equipment for automobile bodies, train bodies, aircraft bodies, ship hulls, etc .; Structures for bridges, buildings, dams, levees, etc .; .

Claims (8)

A method for producing graphene, comprising reacting aluminum carbide with one or more selected from carbon monoxide or a precursor thereof and carbon dioxide or a precursor thereof in the presence of a solvent. The method for producing graphene according to claim 1, wherein the solvent is one or more selected from the group consisting of an organic solvent and an ionic liquid. The said solvent is an organic solvent, The manufacturing method of the graphene of Claim 1 or 2 characterized by the above-mentioned. 4. The method according to claim 1, wherein the solvent is one or more selected from the group consisting of dimethylformamide, ethanol, acetonitrile, 2-propanol, methyl tert-butyl ether, tetrahydrofuran, dimethyl sulfoxide, and methanol. The manufacturing method of the graphene as described in any one of these. The method for producing graphene according to any one of claims 1 to 4, wherein the solvent is one or more selected from the group consisting of dimethylformamide and ethanol. The method for producing graphene according to any one of claims 1 to 5, wherein the solvent is dimethylformamide. The temperature of the said reaction is -100 degreeC-300 degreeC, The manufacturing method of the graphene as described in any one of Claims 1-6 characterized by the above-mentioned. The temperature of the said reaction is -20 degreeC-100 degreeC, The manufacturing method of the graphene as described in any one of Claims 1-7 characterized by the above-mentioned.

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