Preparation method of graphene material

Abstract

The invention discloses a preparation method of a graphene material. A carbon source, an oxidizing gas, a catalytic gas, an inert gas and an environment gas are used as raw material gases; the method comprises the following steps: heating a catalytic reactor to 800-1300 DEG C, introducing oxidizing gas to remove impurities in the reactor, and introducing inert gas to purge so as to ensure the purity of the gas during combustion; introducing a raw material gas carbon source, an oxidizing gas, a catalytic gas, an inert gas and an environment gas into the catalytic reactor, and reacting at 800-1300 DEG C; and performing high-temperature thermal annealing after the reaction, naturally cooling to room temperature after annealing, and cooling to obtain the graphene material. The graphene material prepared by the technical scheme is low in cost, high in yield, high in efficiency and environment-friendly; and large-scale batch production of the high-quality graphene material can be realized by using the method provided by the invention.

Description

1. Technical Field:

[0001] The present invention relates to the technical field of graphene material preparation, and in particular to a method for preparing graphene paper, graphene film or multilayer graphene generated by combustion, that is, the present invention relates to a new method for preparing graphene material. 2. Background technology:

[0002] Graphene is a carbon allotrope with a unique honeycomb structure. Its carbon atoms are tightly and regularly arranged through sp2 hybrid orbitals and p bonds to form a hexagonal two-dimensional crystal structure with a thickness of only one atomic layer. Graphene has high electron mobility, excellent mechanical strength, a large specific surface area, and good thermal conductivity, and has great application and research potential in the fields of electronics, energy, sensing, and catalysis. The properties of graphene are significantly affected by its structural characteristics, including the presence of defects and the number of layers. Single-layer graphene stacked with 3-10 layers can be considered few-layer graphene, while layers with more than 10 layers are considered multilayer graphene. Stacks of single or multilayer graphene can form graphene films and graphene papers.

[0003] Existing graphene production methods include mechanical exfoliation, chemical exfoliation and reduction, silicon carbide epitaxial growth, and chemical vapor deposition (CVD). These methods suffer from low production efficiency, complex steps, high costs, severe environmental pollution, and low product quality. 3. Summary of the invention:

[0004] The technical problem to be solved by the present invention is that the most widely used existing graphene production technology is chemical vapor deposition (CVD), which has the problems of high production cost, low yield, poor transferability, and the need for purification methods to remove residual catalysts. The present invention provides a low-cost, high-yield, high-efficiency, and environmentally friendly preparation method for rapidly generating high-quality, multi-type graphene materials through combustion, that is, the present invention provides a method for preparing graphene materials. Based on the principle of gas-phase catalysis, the present invention mixes a carbon source with an ambient gas, an oxidizing gas, a catalytic gas, and an inert gas. After mixing, the mixture is passed into a high-temperature catalytic reactor for a combustion reaction. By controlling the combustion and annealing time, multilayer graphene, graphene film, or graphene paper is prepared. The method of the present invention can be used to mass-produce high-quality graphene-based materials.

[0005] In order to solve the above problems, the technical solution adopted by the present invention is:

[0006] The present invention provides a method for preparing a graphene-based material, the preparation method comprising the following steps:

[0007] a. Using carbon source, oxidizing gas, catalytic gas, inert gas and ambient gas as raw material gas;

[0008] b. First, heat the catalytic reactor to 800-1300°C, then introduce oxidizing gas to remove impurities in the reactor, and then introduce inert gas for purging to ensure the purity of the gas during combustion;

[0009] c. introducing the raw gas carbon source, oxidizing gas, catalytic gas, inert gas and ambient gas in step a into a catalytic reactor and carrying out a combustion reaction at 800-1300°C;

[0010] d. After the reaction is completed, high temperature thermal annealing is performed, the annealing temperature is 1100-1300°C, and the annealing time is 10-120 minutes;

[0011] e. After annealing, the mixture is naturally cooled to room temperature, and a graphene-like material is obtained after cooling.

[0012] According to the above-mentioned method for preparing graphene-based materials, the graphene-based materials are graphene paper, graphene film or multilayer graphene.

[0013] According to the above-mentioned method for preparing graphene-like materials, the carbon source in step a is at least one of methane, ethane and ethylene; the oxidizing gas is oxygen; the catalytic gas is at least one of ammonia, ammonia water, methylamine and aniline; the inert gas is any one of helium, neon and argon; and the ambient gas is at least one of water, carbon dioxide and nitrogen.

[0014] According to the above-mentioned method for preparing graphene-based materials, the catalytic reactor in step b is a quartz tube furnace.

[0015] According to the above-mentioned method for preparing graphene-based materials, in step b, the catalytic reactor is heated to 1000-1100°C.

[0016] According to the above-mentioned method for preparing graphene-like materials, when the raw gas carbon source, oxidizing gas, catalytic gas, inert gas and ambient gas are introduced into the catalytic reactor in step c, the flow rate of the carbon source is 50-150 sccm, the flow rate of the oxidizing gas is 10-300 sccm, the total flow rate of the catalytic gas is 0.1-20 sccm, the total flow rate of the inert gas is 10-300 sccm, and the flow rate of the ambient gas is 100-800 sccm.

[0017] According to the above-mentioned method for preparing graphene-based materials, the reaction time in step c is 1 to 120 minutes (preferably 5 to 60 minutes).

[0018] According to the above-mentioned method for preparing graphene materials, the proportion of carbon in graphene paper, graphene film or multilayer graphene is ≥90%, and the proportion of oxygen and hydrogen are both ≤10%.

[0019] According to the above-mentioned method for preparing graphene-based materials, when the obtained graphene-based materials are graphene paper or graphene film, the surface resistance of the graphene paper and the graphene film is 1 to 500 Ω / sq.

[0020] The positive beneficial effects of the present invention are:

[0021] 1. The present invention is used to prepare graphene materials. Its production raw materials are mainly various cheap gases. The production equipment is a general quartz tube furnace. The production process time is short. In addition, the graphene paper, graphene film and multilayer graphene generated in the reactor are easy to peel off, and the production cost is low. The schematic diagram of the quartz tube furnace structure is shown in the attached figure. Figure 6 shown.

[0022] 2. The use of the technical solution of the present invention to prepare graphene materials does not require the use of any large amount of chemical reagents, is very environmentally friendly, and is beneficial to environmental protection.

[0023] 3. The technical solution of the present invention is used to prepare graphene materials. Different types of graphene products can be produced by controlling the reaction conditions, such as graphene paper, graphene films and multilayer graphene with different thicknesses. The obtained products are shown in the attached figure. Figure 7 shown.

[0024] 4. The graphene material prepared by the method of the present invention has high quality and integrity, a surface resistance of up to 80Ω / sq, and a size of up to 6cm×6cm.

[0025] In summary, the use of the technical solution of the present invention to prepare graphene materials has low cost, high output, high efficiency, and is environmentally friendly. The present invention is based on the principle of gas-phase catalysis. A carbon source is mixed with an ambient gas, an oxidizing gas, a catalytic gas, and an inert gas. After mixing, the mixture is passed into a high-temperature catalytic reactor for combustion reaction. By controlling the combustion reaction time and annealing time, multilayer graphene, graphene film, or graphene paper is prepared. And the method of the present invention can be used to mass-produce high-quality graphene materials. 4. Description of the accompanying drawings:

[0026] Figure 1 A physical image of the graphene paper sample prepared in Example 1 of the present invention;

[0027] Depend on Figure 1 It can be seen that the graphene paper product prepared in Example 1 of the present invention has greater dimensional integrity and a smooth surface.

[0028] Figure 2 Scanning electron microscope image of the graphene paper prepared in Example 1 of the present invention;

[0029] Depend on Figure 2It can be seen that under the microscopic microscope, it can be observed that there are almost no wrinkles and protrusions on the surface of the prepared graphene paper, and the gaps are typical multi-layer graphene layered structures, showing good mechanical order.

[0030] Figure 3 Scanning electron microscope image of a cross section of the graphene film obtained in Example 2 of the present invention;

[0031] Depend on Figure 3 It can be seen that the typical layered structure shows that the graphene layers are well stacked, and it also confirms that the material inherits the good conductive properties of graphene.

[0032] Figure 4 Raman spectrum of the graphene film prepared in Example 2 of the present invention;

[0033] Figure 4 In the graphene, there are two obvious characteristic peaks: the D peak (1350 cm-1) representing the structural defects of graphene and the G peak (1585 cm-1) representing the graphite crystal, which proves the formation of graphene.

[0034] Figure 5 X-ray photoelectron spectroscopy (XPS) analysis chart of the multilayer graphene prepared in Example 3 of the present invention;

[0035] Depend on Figure 5 It can be seen that elemental analysis shows that the C content of the multilayer graphene is greater than 95%, and the O and N content is less than 3%, indicating that the multilayer graphene prepared by the present invention is of high quality and has few defects.

[0036] Figure 6 A schematic diagram of the structure of a quartz tube furnace used in preparing graphene materials in the present invention;

[0037] The quartz tube furnace used in the present invention mainly includes a temperature controller and an electric heating furnace, and the production equipment can be obtained from a wide range of sources.

[0038] Figure 7 The graphene paper, graphene film and multilayer graphene products prepared by the present invention;

[0039] The present invention can produce a variety of products by controlling different reaction conditions, which illustrates the wide applicability of the present invention. V. Specific implementation methods:

[0040] The present invention is further described below with reference to the following examples, but the scope of protection of the technical solution of the present invention is not limited thereto.

[0041] Example 1:

[0042] The preparation method of the graphene paper of the present invention has the following detailed steps:

[0043] a. Using methane (carbon source), oxygen (oxidizing gas), ammonia (catalytic gas), argon (inert gas) and nitrogen (ambient gas) as raw material gases;

[0044] b. First, heat the quartz tube furnace to 1100°C, then introduce oxygen at a flow rate of 200 sccm for 10 minutes, and then introduce ambient nitrogen at a flow rate of 500 sccm for 10 minutes to remove impurities in the furnace to ensure the purity of the gas during combustion;

[0045] c. Then, the raw material gases methane, oxygen, ammonia, argon, and nitrogen used in step a were introduced into a quartz tube furnace, with the gas flow rates of methane 95 sccm, oxygen 112 sccm, ammonia 1.35 sccm, argon 27 sccm, and nitrogen 515 sccm, respectively; a combustion reaction was carried out at 1100° C. The introduction time of each raw material was 40 minutes, and the pressure in the quartz tube furnace was normal;

[0046] d. After the reaction is completed, turn off all gas supplies, seal all inlets of the quartz tube furnace, and control the temperature of the quartz tube furnace to maintain at 1100°C for 60 minutes for high temperature annealing;

[0047] e. After annealing, it is naturally cooled to room temperature within 180 minutes. Highly conductive graphene paper is generated on the inner wall of the quartz tube furnace. The product can be naturally detached by air blowing.

[0048] The sample prepared in Example 1 has good surface flatness, large area and strong conductivity. Figure 1 As shown in the figure, its conductivity is measured by a multifunctional digital four-probe tester and its square resistance is 60 to 90Ω / sq. The scanning electron microscope image of its fragment is shown in the attached figure. Figure 2 As shown, it exhibits good flatness and layered structure.

[0049] Example 2:

[0050] The method for preparing the graphene film of the present invention has the following detailed steps:

[0051] a. Using methane (carbon source), oxygen (oxidizing gas), ammonia (catalytic gas), argon (inert gas) and carbon dioxide (ambient gas) as raw materials;

[0052] b. First, heat the quartz tube furnace to 1100°C, then introduce oxygen at a flow rate of 150 sccm for 5 minutes, and then introduce ambient nitrogen at a flow rate of 400 sccm for 10 minutes to remove impurities in the furnace to ensure the purity of the gas during combustion;

[0053] c. Then, the raw materials methane, oxygen, ammonia, argon, and carbon dioxide used in step a were introduced into a quartz tube furnace at flow rates of 95 sccm for methane, 136 sccm for oxygen, 2 sccm for ammonia, 27 sccm for argon, and 628 sccm for carbon dioxide. The reaction was carried out at 1100°C, with each raw material introduction time of 15 minutes. The quartz tube furnace was maintained at atmospheric pressure.

[0054] d. After the reaction is completed, turn off all gas supplies, seal all inlets of the quartz tube furnace, and control the temperature of the quartz tube furnace to maintain at 1100°C for 30 minutes for high temperature annealing;

[0055] e. After annealing, cool naturally to room temperature within 120 minutes. A highly conductive graphene film will form on the inner wall of the quartz tube furnace. The product can be naturally detached by air blowing.

[0056] The sample prepared in Example 2 has good surface flatness, large area, and strong conductivity. Its conductivity is measured by a multifunctional digital four-probe tester and its square resistance is 10-70Ω / sq. The thickness of the graphene film cross section is about 650nm. The scanning electron microscope image is shown in the attached figure. Figure 3 As shown in the figure, it shows a good stacking and layered structure. Figure 4 ) can identify obvious D peak, G peak and 2D peak, and the intensity ratio of D peak to G peak (I D / I G ) is approximately 0.9.

[0057] Example 3:

[0058] The preparation method of multilayer graphene of the present invention has the following detailed steps:

[0059] a. Using methane (carbon source), oxygen (oxidizing gas), ammonia (catalytic gas), argon (inert gas) and carbon dioxide (ambient gas) as raw materials;

[0060] b. First, heat the quartz tube furnace to 1100°C, then introduce oxygen at a flow rate of 100 sccm for 5 minutes, and then introduce ambient nitrogen at a flow rate of 300 sccm for 10 minutes to remove impurities in the furnace to ensure the purity of the gas during combustion;

[0061] c. Then, the raw material gases methane, oxygen, ammonia, argon, and carbon dioxide used in step a were introduced into a quartz tube furnace, with the flow rates of methane 95 sccm, oxygen 112 sccm, ammonia 1.57 sccm, argon 27 sccm, and carbon dioxide 515 sccm; a combustion reaction was carried out at 1100° C. The introduction time of each raw material was 7 minutes, and the pressure in the quartz tube furnace was normal;

[0062] d. After the reaction is completed, turn off all gas supplies and seal all inlets of the quartz tube furnace; cool naturally to room temperature within 120 minutes;

[0063] e. After cooling to room temperature, 500 sccm of nitrogen was introduced again for 10 minutes to remove impurity gases in the quartz tube furnace; all inlets of the quartz tube furnace were sealed and reheated, and the temperature was increased to 1100°C at a heating rate of 10°C / min; the constant temperature was maintained for 30 minutes and then thermally annealed, and then naturally cooled to room temperature within 120 minutes; multilayer graphene was generated on the inner wall of the quartz tube furnace, and the sample was analyzed by X-ray photoelectron spectroscopy (XPS) (see Appendix for details). Figure 5 The sample obtained had a main component carbon content of 96%, and oxygen and nitrogen content of 2.5% and 1.5% respectively, indicating good quality.

Claims

1. A method for preparing a graphene material, characterized in that: The preparation method comprises the following steps: a. Using carbon source, oxidizing gas, catalytic gas, inert gas and environmental gas as raw material gas; b. First, the catalytic reactor is heated to 800-1300°C, and then the oxidizing gas is introduced to remove impurities in the reactor, and then the inert gas is introduced for purging to ensure the purity of the gas during combustion; c. introducing the raw gas carbon source, oxidizing gas, catalytic gas, inert gas and ambient gas in step a into a catalytic reactor and carrying out a combustion reaction at 800-1300° C.; d. After the reaction is completed, high temperature thermal annealing is performed, the annealing temperature is 1100-1300°C, and the annealing time is 10-120min; e. After annealing, the mixture is naturally cooled to room temperature, and a graphene-like material is obtained after cooling.

2. The method for preparing the graphene-based material according to claim 1, characterized in that: The graphene material is graphene paper, graphene film or multilayer graphene.

3. The method for preparing graphene-based materials according to claim 1, characterized in that: In step a, the carbon source is at least one of methane, ethane and ethylene; the oxidizing gas is oxygen; the catalytic gas is at least one of ammonia, ammonia water, methylamine and aniline; the inert gas is any one of helium, neon and argon; and the ambient gas is at least one of water, carbon dioxide and nitrogen.

4. The method for preparing the graphene-based material according to claim 1, characterized in that: The catalytic reactor in step b is a quartz tube furnace.

5. The method for preparing graphene-based materials according to claim 1, characterized in that: In step b, the catalytic reactor is heated to 1000-1100°C.

6. The method for preparing graphene-based materials according to claim 1, characterized in that: In step c, when the raw gas carbon source, oxidizing gas, catalytic gas, inert gas and ambient gas are introduced into the catalytic reactor, the flow rate of the carbon source is 50-150 sccm, the flow rate of the oxidizing gas is 10-300 sccm, the total flow rate of the catalytic gas is 0.1-20 sccm, the total flow rate of the inert gas is 10-300 sccm, and the flow rate of the ambient gas is 100-800 sccm.

7. The method for preparing graphene-based materials according to claim 1, characterized in that: The reaction time in step c is 1 to 120 minutes.

8. The method for preparing graphene-based materials according to claim 1, characterized in that: The proportion of carbon element in graphene paper, graphene film or multilayer graphene is ≥90%, and the proportion of oxygen element and the proportion of hydrogen element are both ≤10%.

9. The method for preparing graphene-based materials according to claim 1, characterized in that: When the obtained graphene material is graphene paper or graphene film, the surface resistance of the graphene paper and the graphene film is 1 to 500 Ω / sq.

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