A device and method for preparing thin-layer graphene

Abstract

The present invention provides a device and method for preparing thin-layer graphene, which includes a high-temperature molten metal pool and a gas injection device. The method utilizes a low-temperature gas jet to form a gas column with a certain height in the liquid molten metal of the high-temperature molten metal pool by means of the gas injection device, so that the cracking products (metal carbides) generated by the reaction of the high-temperature molten metal and gaseous hydrocarbons are in contact with the gas column. The gas column manufactured by the low-temperature gas jet provides conditions and space for graphene to precipitate. This is simpler and safer than a device that draws out the high-temperature molten metal for cooling and then returns it, and can save costs by 30%-50%. The resulting product has a large specific surface area, high crystallinity, a small number of layers (1-3 layers), and a low preparation cost, and the process can be operated continuously. In addition, due to the high-speed gas jet, a gas column area is formed in the molten metal pool, and graphene nanoribbons with a large aspect ratio can be prepared at the same time.

Description

Technical Field

[0001] The present invention relates to the technical fields of chemical vapor deposition and chemical liquid deposition and nanomaterial processing, and in particular to a device and method for preparing thin-layer graphene. Background Art

[0002] Graphene is a two-dimensional SP 2 Hybrid carbon materials offer advantages such as large surface area, good conductivity, or controllable band gaps. Powdered graphene can be used as capacitor electrode materials, as a conductive agent in lithium-ion batteries, and as an environmental adsorbent. Narrow graphene nanoribbons can be used as semiconductors and sensors. Magic-angle graphene materials with double or triple layers and controllable stacking angles are promising candidates for future superconductors. The preparation of high-quality thin-layer graphene has long been at the forefront of nanotechnology.

[0003] Currently, graphene is primarily produced using CVD-silicon or oxide-templated methods, or by graphite intercalation and exfoliation. Solid-phase catalytic CVD methods suffer from low carbon source conversion rates, high costs, and low purity. Furthermore, highly crystalline graphene requires a high-temperature growth environment. To avoid thermal cracking, methane is often used as the carbon source for growth, resulting in lower yields, high catalyst consumption, and high separation and purification costs.

[0004] Recently, significant progress has been made in the production of graphene from methane using high-temperature molten metal cracking. Graphene can be produced by heating copper, nickel, or their alloys at temperatures between 800 and 1400°C. High conversion rates have been reported. However, due to the high viscosity of the molten metal, the gas (in the form of bubbles) travels slowly and has a long residence time within it. Consequently, the resulting product is mostly multi-layer graphene, with inferior performance compared to thin-layer graphene. Summary of the Invention

[0005] In response to the above-mentioned problems existing in the prior art, the present invention provides a device and method for preparing thin-layer graphene. By using this device, thin-layer graphene products with large specific surface area, high crystallinity, and few layers (1-3 layers) can be obtained, and the preparation cost is low, and the process can be operated continuously.

[0006] The specific content of the invention is as follows:

[0007] In a first aspect, the present invention provides a device for preparing thin-layer graphene, the device comprising:

[0008] A high-temperature molten metal pool 1 containing liquid molten metal is divided into a liquid phase region 1-1 and a gas phase region 1-2 by the liquid surface of the liquid molten metal. The liquid phase region 1-1 is provided with a raw material inlet 3. The high-temperature molten metal pool 1 is used to crack gaseous hydrocarbons entering the liquid phase region 1-1 through the raw material inlet 3 under the action of the liquid molten metal, and form a graphene carbon layer on the metal surface to obtain metal carbide.

[0009] A gas injection device 2 is provided in the gas phase zone 1-2, and the gas injection device 2 includes a plurality of injection pipes 2-1, and the nozzles of the plurality of injection pipes 2-1 are provided on the side of the liquid phase zone 1-1 close to the high-temperature molten metal pool 1; the gas injection device 2 is used to spray an inert gas with a certain flow rate and flow rate through the nozzles of the plurality of injection pipes 2-1 toward the liquid phase zone 1-1, forming a plurality of gas columns with a width of 4-100 μm in the liquid phase zone 1-1, and the metal carbide contacts the gas columns, and is rapidly supercooled to precipitate a thin layer of graphene.

[0010] Optionally, the height between the nozzle and the liquid phase region 1 - 1 is 0.001-0.1 times the diameter of the high-temperature molten metal pool 1 .

[0011] Optionally, the gas phase zone 1-2 is further provided with a graphene product outlet 4 and a mixed gas outlet 5, and the mixed gas outlet 5 is connected to the gas injection device 2 for secondary utilization of the mixed gas collected in the gas phase zone 1-2 through the gas injection device 2.

[0012] In a second aspect, the present invention provides a method for preparing thin-layer graphene, which is applicable to the thin-layer graphene preparation device described in the first aspect above, and the method comprises:

[0013] Gaseous hydrocarbons are introduced into the liquid phase region 1-1 of the high-temperature molten metal pool 1 through the raw material inlet 3 at a pressure of 1-5 MPa. The gaseous hydrocarbons are cracked by the liquid molten metal and a graphene carbon layer is formed on the metal surface to obtain metal carbide.

[0014] A low-temperature inert gas with a certain flow rate and flow rate is sprayed toward the liquid phase region 1-1 through the nozzles of multiple injection pipes 2-1 of the gas injection device 2, forming multiple gas columns with a width of 4-100 μm in the liquid phase region 1-1. The metal carbide contacts the gas columns and is rapidly supercooled to precipitate a thin layer of graphene.

[0015] The mixed gas collected in the gas phase region 1-2 of the high-temperature molten metal pool 1 is sent to the gas injection device 2 through a circulation pipeline for gas recycling.

[0016] Optionally, the liquid molten metal is formed by melting mixed metal powder under the conditions of applying voltage and current, and the temperature of the molten metal is 600-1400 o C, the mixed metal powder is formed by mixing one or more of copper, nickel, iron, molybdenum and manganese with one or more of aluminum, gallium, magnesium and tin, and the particle size of the mixed metal powder is 1-100 μm.

[0017] Optionally, the molecular weight of the gaseous hydrocarbons is 16-300.

[0018] Optionally, the temperature of the inert gas is 25-300°C;

[0019] The inert gas includes one or more of hydrogen, nitrogen, helium and argon.

[0020] Optionally, the gas flow rate of the inert gas is 30-150 m / s.

[0021] Optionally, the height of the gas column is 2 / 3-4 / 5 of the height of the liquid phase region 1-1.

[0022] Optionally, the thin-layer graphene is graphene with 1-3 layers, a length of 0.5-200 μm, and a width of 2-20,000 nm.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] The present invention provides a thin-layer graphene preparation device, which includes: a high-temperature molten metal pool 1, in which liquid molten metal is contained, and the high-temperature molten metal pool 1 is divided into a liquid phase region 1-1 and a gas phase region 1-2 by the liquid surface of the liquid molten metal, and the liquid phase region 1-1 is provided with a raw material inlet 3; the high-temperature molten metal pool 1 is used to crack the gaseous hydrocarbons entering the liquid phase region 1-1 through the raw material inlet 3 under the action of the liquid molten metal, and form a graphene carbon layer on the metal surface to obtain metal carbide; the gas The gas injection device 2 is positioned within the gas phase region 1-2 and comprises multiple injection tubes 2-1, the nozzles of which are positioned near the liquid phase region 1-1 of the high-temperature molten metal pool 1. The gas injection device 2 is configured to inject an inert gas at a predetermined velocity and flow rate through the nozzles of the multiple injection tubes 2-1 into the liquid phase region 1-1, forming multiple gas columns with a width of 4-100 μm in the liquid phase region 1-1. This allows metal carbides to contact the gas columns, rapidly supercooling and precipitating thin layers of graphene. The present invention utilizes low-temperature gas jets, using the gas injection device 2 to form gas columns of a predetermined height within the liquid molten metal. These gas columns create the conditions and space for graphene precipitation. This method is simpler and safer than systems that draw high-temperature molten metal out for cooling and then return it, and can save 30%-50% in costs. Furthermore, the high-velocity gas jets create gas columns within the molten metal pool 1, providing ample space for the precipitation of graphene with a large aspect ratio. Therefore, this method can also produce nanographene ribbons with a large aspect ratio, and the cost is 90% lower than traditional chemical synthesis or laser etching methods.

[0025] The present invention also provides a method for producing thin-layer graphene. Hydrocarbons are introduced into the bottom of a molten metal pool 1, where they are cracked at high temperature to produce metal carbides. High-pressure, low-temperature inert gas is then injected into the molten metal pool 1 as high-velocity gas jets via a gas injection device 2. This creates multiple localized supercooled gas columns, promoting supercooling and condensation of the metal carbides, ultimately leading to the precipitation of graphene, which is then rapidly carried out of the molten metal pool 1. The mixed gas, consisting of unreacted hydrocarbons, hydrogen generated by cracking of gaseous hydrocarbons, and inert gas, accumulated in the gas phase region 1-2 of the molten metal pool 1, can be recycled through the gas injection device 2, improving gas utilization and reducing gas costs. The resulting graphene is a thin-layer graphene with 1-3 layers, a length of 0.5-200 μm, and a width of 2-20,000 nm. This method offers the advantages of a large specific surface area, high crystallinity, a small number of layers, continuous process operation, and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 A schematic diagram of a device for preparing thin-layer graphene provided by an embodiment of the present invention is shown;

[0028] Figure 2 The flowchart of the method for preparing thin-layer graphene provided by an embodiment of the present invention is shown.

[0029] Among them, Figure 1 The reference numerals involved are explained as follows:

[0030] 1-high-temperature molten metal pool, 1-1-liquid phase zone, 1-2-gas phase zone, 2-gas injection device, 2-1-injection pipe, 3-raw material inlet, 4-graphene product outlet, 5-mixed gas outlet. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means a limitation on the present invention and its application or use. Based on the embodiments of the present invention, any product that is identical or similar to the present invention and is obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts falls within the scope of protection of the present invention. In addition, all other embodiments obtained by ordinary technicians in this field without carrying out creative work fall within the scope of protection of the present invention.

[0032] Where specific experimental steps or conditions are not specified in the examples, the conventional experimental steps or conditions described in the prior art in the art may be used. Reagents and other instruments used, for which the manufacturer is not specified, are commercially available conventional reagent products. Furthermore, the accompanying drawings are merely schematic illustrations of embodiments of the present invention and are not necessarily drawn to scale. Identical reference numerals in the figures denote identical or similar parts, and their repeated descriptions will be omitted. Some block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0033] Technologies, methods, and apparatus known to ordinary technicians in the relevant field may not be discussed in detail, but where appropriate, such technologies, methods, and apparatus should be considered part of the authorization specification.

[0034] In the description of the present invention, it should be understood that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0035] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0036] Before describing in detail the device and method for preparing thin-layer graphene provided by the present invention, it is necessary to describe the related technologies as follows:

[0037] In the prior art, when producing graphene by cracking hydrocarbons with high-temperature molten metal, carbon atoms in the hydrocarbon gas source diffuse onto the surface of the hot metal substrate. These carbon atoms are arranged in a two-dimensional crystal structure, forming a carbon layer of graphene on the metal surface. To isolate the graphene product, the reaction chamber must be cooled to first cool the metal substrate and the graphene adhered thereto. Chemical solvents or mechanical means are then used to separate the metal substrate from the graphene. Furthermore, due to the high viscosity of the liquid molten metal and the time required for cooling, the resulting graphene product is mostly multi-layer graphene. Therefore, obtaining thin-layer graphene through the existing process of cracking hydrocarbons with high-temperature molten metal is quite difficult.

[0038] To this end, the present invention aims to provide an improved apparatus for producing graphene by cracking hydrocarbons using high-temperature molten metal. This invention integrates a high-temperature molten metal pool with a gas injection device. The gas injection device injects an inert gas with a certain flow rate and flow rate into the high-temperature molten metal pool, creating multiple localized supercooled gas columns. The cracking products (graphene) generated by the reaction of the high-temperature molten metal and gaseous hydrocarbons come into contact with the gas columns, rapidly supercooling and precipitating. This rapid separation method effectively reduces the thickness of the generated graphene layer, resulting in thin-layer graphene. Specific embodiments are as follows:

[0039] In a first aspect, the present invention provides a device for preparing thin-layer graphene. Figure 1 A schematic diagram of a thin-layer graphene preparation device provided by an embodiment of the present invention is shown in FIG. Figure 1 As shown, the device includes: a high-temperature molten metal pool 1 and a gas injection device 2.

[0040] The high temperature molten metal pool 1 contains liquid molten metal, which is generally formed by melting mixed metal powder under the conditions of applied voltage and current. The temperature of the molten metal is 600-1400 o C, the mixed metal powder is formed by mixing one or more of copper, nickel, iron, molybdenum and manganese with one or more of aluminum, gallium, magnesium and tin.

[0041] See also Figure 1 The high-temperature molten metal pool 1 is divided into a liquid phase region 1-1 and a gas phase region 1-2 by the liquid molten metal surface. Specifically, the liquid phase region 1-1 is the region not containing the liquid molten metal. A raw material inlet 3 is provided in the liquid phase region 1-1, specifically at the bottom of the high-temperature molten metal pool 1, to facilitate sufficient contact between the gaseous hydrocarbons and the high-temperature molten metal.

[0042] The high-temperature molten metal pool 1 is used to crack the gaseous hydrocarbons entering the liquid phase region 1-1 through the raw material inlet 3 under the action of liquid molten metal. The carbon atoms in the gaseous hydrocarbons diffuse on the surface of the high-temperature molten metal substrate and are arranged in a two-dimensional crystal structure to form a graphene carbon layer on the metal surface.

[0043] See also Figure 1 The gas injection device 2 is arranged in the gas phase zone 1-2, that is, located above the liquid phase zone 1-1. The gas injection device 2 includes a plurality of injection pipes 2-1, and the nozzles of the plurality of injection pipes 2-1 are arranged on the side of the liquid phase zone 1-1 close to the high-temperature molten metal pool 1.

[0044] The gas injection device 2 injects an inert gas of a predetermined velocity and flow rate into the liquid phase region 1-1 through the nozzles of multiple injection tubes 2-1 using high-speed gas jets. The high-speed gas flow forms multiple gas columns within the high-temperature molten metal in the liquid phase region 1-1. The number of gas columns formed corresponds to the number of injection tubes. These gas columns create multiple localized undercooling zones within the high-temperature molten metal, causing the graphene carbon layers in these zones to rapidly undercool and precipitate out of the metal surface.

[0045] In some embodiments, the height between the nozzle of the injection pipe 2-1 and the liquid phase region 1-1 is 0.001-0.1 times the diameter of the high-temperature molten metal pool 1 to ensure that the formed gas column meets the required height.

[0046] See also Figure 1 The gas phase region 1-2 is further provided with a graphene product outlet 4 and a mixed gas outlet 5. The mixed gas outlet 5 is connected to the gas injection device 2. The mixed gas outlet 5 is used to pass the mixed gas composed of unreacted hydrocarbons, hydrogen generated by cracking of gaseous hydrocarbons, and inert gas collected in the gas phase region 1-2 through the gas injection device 2 for secondary utilization, thereby improving gas utilization and reducing gas costs.

[0047] The present invention utilizes a low-temperature gas jet, using a gas injection device 2 to form a gas column of a certain height within the liquid molten metal. This column creates the conditions and space for graphene precipitation. This is simpler and safer than devices that draw high-temperature molten metal out for cooling and then return it, saving 30%-50% in costs. Furthermore, the high-speed gas jet creates a gas column zone within the molten metal pool 1, providing ample space for the precipitation of graphene with a large aspect ratio. Therefore, this method can also produce nanographene ribbons with a large aspect ratio. It also reduces costs by 90% compared to traditional chemical synthesis or laser etching methods.

[0048] In a second aspect, the present invention provides a method for preparing thin-layer graphene. Figure 2 The flow chart of the method for preparing thin-layer graphene provided by the embodiment of the present invention is shown as follows: Figure 2 As shown, the method is applicable to the thin-layer graphene preparation device described in the first aspect above, and the method includes:

[0049] S1, introducing gaseous hydrocarbons into the liquid phase region 1-1 of the high-temperature molten metal pool 1 through the raw material inlet 3, the gaseous hydrocarbons are cracked by the liquid molten metal, and a graphene carbon layer is formed on the metal surface to obtain metal carbide;

[0050] S2. A low-temperature inert gas with a certain flow rate and flow rate is sprayed toward the liquid phase region 1-1 through the nozzles of the multiple injection pipes 2-1 of the gas injection device 2, forming multiple gas columns with a width of 4-100 μm in the liquid phase region 1-1. The metal carbide contacts the gas columns and is rapidly supercooled to precipitate thin layers of graphene.

[0051] S3. The mixed gas collected in the gas phase region 1-2 of the high-temperature molten metal pool 1 is sent to the gas injection device 2 through a circulation pipeline for gas recycling.

[0052] In specific implementation, before the gaseous hydrocarbon is introduced into the high temperature molten metal pool 1, a certain voltage and current are applied to the high temperature molten metal pool 1 containing the mixed metal powder to melt the mixed metal powder and form a temperature of 600-1400 oC liquid molten metal. The gaseous hydrocarbons have a molecular weight of 16-300 and are introduced into the liquid molten metal through the raw material inlet 3 at a pressure of 1-5 MPa. The gaseous hydrocarbons, in the form of tiny bubbles, come into contact with the high-temperature molten metal. The high-temperature molten metal cracks the hydrocarbons, generating hydrogen and forming a graphene carbon layer on the metal surface, resulting in metal carbide. Furthermore, an inert gas (temperature 25-300°C) composed of one or more of hydrogen, nitrogen, helium, and argon is sprayed onto the liquid molten metal through multiple injection pipes 2-1 provided in the gas injection device 2. In specific implementations, the gas velocity in the injection pipes 2-1 is controlled to 30-150 m / s, forming multiple gas columns with a width of 4-100 μm in the molten metal pool. The inert gas flow rate is controlled so that the height of the formed gas column is 2 / 3-4 / 5 of the height of the liquid phase region 1-1, ensuring sufficient contact area between the graphene and the gas column, allowing for rapid supercooling and precipitation. The result is a thin layer of graphene with 1-3 layers, a length of 0.5-200 μm, and a width of 2-20,000 nm. The mixed gas composed of unreacted hydrocarbons, hydrogen generated by cracking gaseous hydrocarbons, and inert gas accumulated in the gas phase region 1-2 of the high-temperature molten metal pool 1 can be fed into the gas injection device 2 through a circulation pipeline for recycling, thereby improving gas utilization and reducing gas costs.

[0053] In order to enable those skilled in the art to more clearly understand the present invention, the device and method for preparing thin-layer graphene according to the present invention are now described in detail through the following examples.

[0054] Example 1

[0055] according to Figure 1 As shown, the thin-layer graphene preparation device is assembled so that the distance between the lowermost end of the injection pipe of the gas injection device 2 and the liquid phase region 1-1 of the high-temperature molten metal pool 1 is 0.001 times the diameter of the high-temperature molten metal pool 1.

[0056] Mixed metal powder (90% copper, 5% aluminum, 5% tin, particle size range 1-5 μm) was placed in a high-temperature molten metal pool 1, and voltage and current were applied at a temperature of 850 o C, the metal powder turns into liquid molten metal, dividing the high-temperature molten metal pool 1 into a liquid phase region 1-1 and a gas phase region 1-2.

[0057] Gaseous hydrocarbons (molecular weight 16) are introduced into the bottom of the liquid molten metal through the raw material inlet 3 at a pressure of 1 MPa. The gaseous hydrocarbons react with the liquid metal in the form of extremely small bubbles, cracking the hydrocarbons to generate hydrogen and forming a graphene carbon layer on the metal surface to form metal carbide.

[0058] Inert gas (Ar, 25°C) is sprayed through the nozzles of multiple injection tubes 2-1 of gas injection device 2 toward the molten metal in liquid phase region 1-1. The gas velocity in the injection tubes of gas injection device 2 is controlled at 30 m / s, forming multiple gas columns with a width of 100 μm in the high-temperature molten metal pool 1. The inert gas flow rate is controlled so that the length of the gas columns occupies two-thirds of the height of liquid phase region 1-1.

[0059] The metal carbide comes into contact with the low-temperature inert gas column, rapidly supercooling and precipitating thin layers of graphene (1-3 layers, 0.5 μm in length, 2 nm in width). The thin graphene rapidly rises along the gas column to the gas phase region 1-2 above the high-temperature molten metal pool 1. Carried by the airflow, it exits the device through the graphene product outlet 4 of the high-temperature molten metal pool 1.

[0060] Incompletely converted hydrocarbons, hydrogen generated by cracking, and inert gases are collected in the gas phase zone 1-2 and leave the device through the mixed gas outlet 5. Part of the gas (30%) from the mixed gas outlet 5 is used for circulation operation and returned to the gas injection device 2 through the circulation pipeline for recycling.

[0061] Repeat the above steps to make the process continuous.

[0062] Example 2

[0063] according to Figure 1 As shown, the thin-layer graphene preparation device is assembled so that the distance between the lowermost end of the injection pipe of the gas injection device 2 and the liquid phase region 1-1 of the high-temperature molten metal pool 1 is 0.1 times the diameter of the high-temperature molten metal pool 1.

[0064] The mixed metal powder (100% nickel, particle size range 1-5 μm) was placed in a high temperature molten metal pool 1, and voltage and current were applied at a temperature of 1400 o C, the metal powder turns into liquid molten metal, dividing the high-temperature molten metal pool 1 into a liquid phase region 1-1 and a gas phase region 1-2.

[0065] Gaseous hydrocarbons (molecular weight 160-260) are introduced into the bottom of the liquid molten metal through the raw material inlet 3 at a pressure of 5 MPa. The gaseous hydrocarbons react with the liquid metal in the form of extremely small bubbles, cracking the hydrocarbons to generate hydrogen and forming a graphene carbon layer on the metal surface to form metal carbide.

[0066] Inert gas (H2, 300°C) is sprayed through the nozzles of multiple injection tubes 2-1 of gas injection device 2 toward the molten metal in liquid phase region 1-1. The gas velocity in the injection tubes of gas injection device 2 is controlled at 150 m / s, forming multiple gas columns with a width of 4 μm in the high-temperature molten metal pool 1. The inert gas flow rate is controlled so that the length of the gas columns occupies 4 / 5 of the height of liquid phase region 1-1.

[0067] The metal carbide comes into contact with the low-temperature inert gas column, rapidly supercooling and precipitating thin layers of graphene (1-3 layers, 50 μm long, 2 nm wide). The thin graphene rapidly rises along the gas column to the gas phase region 1-2 above the high-temperature molten metal pool 1. Carried by the airflow, it exits the device through the graphene product outlet 4 of the high-temperature molten metal pool 1.

[0068] Incompletely converted hydrocarbons, hydrogen generated by cracking, and inert gases are collected in the gas phase zone 1-2 and leave the device through the mixed gas outlet 5. Part of the gas (50%) from the mixed gas outlet 5 is used for circulation operation and returned to the gas injection device 2 through the circulation pipeline for recycling.

[0069] Repeat the above steps to make the process continuous.

[0070] Example 3

[0071] according to Figure 1 As shown, the thin-layer graphene preparation device is assembled so that the distance between the lowermost end of the injection pipe of the gas injection device 2 and the liquid phase region 1-1 of the high-temperature molten metal pool 1 is 0.05 times the diameter of the high-temperature molten metal pool 1.

[0072] The mixed metal powder (100% copper, particle size range 1-100 μm) was placed in a high temperature molten metal pool 1, and voltage and current were applied at a temperature of 900 o C, the metal powder turns into liquid molten metal, dividing the high-temperature molten metal pool 1 into a liquid phase region 1-1 and a gas phase region 1-2.

[0073] Gaseous hydrocarbons (molecular weight 78-120) are introduced into the bottom of the liquid molten metal through the raw material inlet 3 at a pressure of 2 MPa. The gaseous hydrocarbons react with the liquid metal in the form of extremely small bubbles, cracking the hydrocarbons to generate hydrogen and forming a graphene carbon layer on the metal surface to form metal carbide.

[0074] Inert gas (50% H₂ and 50% N₂, 25-300°C) is sprayed through the nozzles of multiple injection tubes 2-1 of gas injection device 2 toward the molten metal in liquid phase region 1-1. The gas velocity in the injection tubes of gas injection device 2 is controlled at 70 m / s, forming multiple gas columns with a width of 10 μm in the high-temperature molten metal pool 1. The inert gas flow rate is controlled so that the length of the gas columns occupies 3 / 4 of the height of liquid phase region 1-1.

[0075] The metal carbide comes into contact with the low-temperature inert gas column, rapidly supercooling and precipitating a thin layer of graphene (1-3 layers, 20 μm in length, 20,000 nm in width). The thin graphene rapidly rises along the gas column to the gas phase region 1-2 above the high-temperature molten metal pool 1. Carried by the airflow, it exits the device through the graphene product outlet 4 of the high-temperature molten metal pool 1.

[0076] Incompletely converted hydrocarbons, hydrogen generated by cracking, and inert gases are collected in the gas phase zone 1-2 and leave the device through the mixed gas outlet 5. Part of the gas (100%) from the mixed gas outlet 5 is used for circulation operation and returned to the gas injection device 2 through the circulation pipeline for recycling.

[0077] Repeat the above steps to make the process continuous.

[0078] Example 4

[0079] according to Figure 1 As shown, the thin-layer graphene preparation device is assembled so that the distance between the lowermost end of the injection pipe of the gas injection device 2 and the liquid phase region 1-1 of the high-temperature molten metal pool 1 is 0.002 times the diameter of the high-temperature molten metal pool 1.

[0080] Mixed metal powder (87% copper, 10% nickel, 3% magnesium, particle size range 2-10 μm) was placed in a high-temperature molten metal pool 1, and voltage and current were applied at a temperature of 1020 o C, the metal powder turns into liquid molten metal, dividing the high-temperature molten metal pool 1 into a liquid phase region 1-1 and a gas phase region 1-2.

[0081] Gaseous hydrocarbons (molecular weight 16-44 and 200-300) are introduced into the bottom of the liquid molten metal through the raw material inlet 3 at a pressure of 1.5 MPa. The gaseous hydrocarbons react with the liquid metal in the form of extremely small bubbles, cracking the hydrocarbons to produce hydrogen and forming a graphene carbon layer on the metal surface to form metal carbide.

[0082] Inert gas (He, 60°C) is sprayed through the nozzles of multiple injection tubes 2-1 of gas injection device 2 toward the molten metal in liquid phase region 1-1. The gas velocity in the injection tubes of gas injection device 2 is controlled to 100 m / s, forming multiple gas columns with a width of 20 μm in the high-temperature molten metal pool 1. The inert gas flow rate is controlled so that the length of the gas columns occupies 3 / 4 of the height of liquid phase region 1-1.

[0083] The metal carbide comes into contact with the low-temperature inert gas column, rapidly supercooling and precipitating thin layers of graphene (1-3 layers, 200 μm long, 2 nm wide). The thin graphene rapidly rises along the gas column to the gas phase region 1-2 above the high-temperature molten metal pool 1. Carried by the airflow, it exits the device through the graphene product outlet 4 of the high-temperature molten metal pool 1.

[0084] Incompletely converted hydrocarbons, hydrogen generated by cracking, and inert gases are collected in the gas phase zone 1-2 and leave the device through the mixed gas outlet 5. Part of the gas (70%) from the mixed gas outlet 5 is used for circulation operation and returned to the gas injection device 2 through the circulation pipeline for recycling.

[0085] Repeat the above steps to make the process continuous.

[0086] Example 5

[0087] according to Figure 1 As shown, the thin-layer graphene preparation device is assembled so that the distance between the lowermost end of the injection pipe of the gas injection device 2 and the liquid phase region 1-1 of the high-temperature molten metal pool 1 is 0.07 times the diameter of the high-temperature molten metal pool 1.

[0088] Mixed metal powder (40% nickel, 10% molybdenum, 50% magnesium, particle size range 20-45 μm) was placed in a high-temperature molten metal pool 1, and voltage and current were applied at a temperature of 1320 o C, the metal powder turns into liquid molten metal, dividing the high-temperature molten metal pool 1 into a liquid phase region 1-1 and a gas phase region 1-2.

[0089] Gaseous hydrocarbons (molecular weight 16) are introduced into the bottom of the liquid molten metal through the raw material inlet 3 at a pressure of 2.5 MPa. The gaseous hydrocarbons react with the liquid metal in the form of extremely small bubbles, cracking the hydrocarbons to generate hydrogen and forming a graphene carbon layer on the metal surface to form metal carbide.

[0090] Inert gas (20% Ar and 80% H2, 300°C) is sprayed through the nozzles of multiple injection tubes 2-1 of gas injection device 2 toward the molten metal in liquid phase region 1-1. The gas velocity in the injection tubes of gas injection device 2 is controlled at 80 m / s, forming multiple gas columns with a width of 80 μm in the high-temperature molten metal pool 1. The inert gas flow rate is controlled so that the length of the gas columns occupies 4 / 5 of the height of liquid phase region 1-1.

[0091] The metal carbide comes into contact with the low-temperature inert gas column, rapidly supercooling and precipitating a thin layer of graphene (1-2 layers, 40 μm in length, 200 nm in width). The thin graphene rapidly rises along the gas column to the gas phase region 1-2 above the high-temperature molten metal pool 1. Carried by the airflow, it exits the device through the graphene product outlet 4 of the high-temperature molten metal pool 1.

[0092] Incompletely converted hydrocarbons, hydrogen generated by cracking, and inert gases are collected in the gas phase zone 1-2 and leave the device through the mixed gas outlet 5. Part of the gas (30%) from the mixed gas outlet 5 is used for circulation operation and returned to the gas injection device 2 through the circulation pipeline for recycling.

[0093] Repeat the above steps to make the process continuous.

[0094] Example 6

[0095] according to Figure 1 As shown, the thin-layer graphene preparation device is assembled so that the distance between the lowermost end of the injection pipe of the gas injection device 2 and the liquid phase region 1-1 of the high-temperature molten metal pool 1 is 0.004 times the diameter of the high-temperature molten metal pool 1.

[0096] Mixed metal powder (5% iron, 20% copper, 20% tin, 55% magnesium, particle size range 20-100 μm) is placed in a high-temperature molten metal pool 1, and voltage and current are applied at a temperature of 600 o C, the metal powder turns into liquid molten metal, dividing the high-temperature molten metal pool 1 into a liquid phase region 1-1 and a gas phase region 1-2.

[0097] Gaseous hydrocarbons (molecular weight 16-92) are introduced into the bottom of the liquid molten metal through the raw material inlet 3 at a pressure of 3 MPa. The gaseous hydrocarbons react with the liquid metal in the form of extremely small bubbles, cracking the hydrocarbons to generate hydrogen and forming a graphene carbon layer on the metal surface to form metal carbide.

[0098] Inert gas (N2, 30°C) is sprayed through the nozzles of multiple injection tubes 2-1 of gas injection device 2 toward the molten metal in liquid phase region 1-1. The gas velocity in the injection tubes of gas injection device 2 is controlled at 120 m / s, forming multiple gas columns with a width of 6 μm in the high-temperature molten metal pool 1. The inert gas flow rate is controlled so that the length of the gas columns occupies 3 / 4 of the height of liquid phase region 1-1.

[0099] The metal carbide comes into contact with the low-temperature inert gas column, rapidly supercooling and precipitating a thin layer of graphene (1-3 layers, 10 μm in length, 10 nm in width). The thin graphene rapidly rises along the gas column to the gas phase region 1-2 above the high-temperature molten metal pool 1. Carried by the airflow, it exits the device through the graphene product outlet 4 of the high-temperature molten metal pool 1.

[0100] Incompletely converted hydrocarbons, hydrogen generated by cracking, and inert gases are collected in the gas phase zone 1-2 and leave the device through the mixed gas outlet 5. Part of the gas (40%) from the mixed gas outlet 5 is used for circulation operation and returned to the gas injection device 2 through the circulation pipeline for recycling.

[0101] Repeat the above steps to make the process continuous.

[0102] Example 7

[0103] according to Figure 1 As shown, the thin-layer graphene preparation device is assembled so that the distance between the lowermost end of the injection pipe of the gas injection device 2 and the liquid phase region 1-1 of the high-temperature molten metal pool 1 is 0.08 times the diameter of the high-temperature molten metal pool 1.

[0104] Mixed metal powder (75% copper, 10% gallium, 10% magnesium, 5% manganese, with a particle size range of 70-100 μm) was placed in a high-temperature molten metal pool 1, and voltage and current were applied at a temperature of 990 o C, the metal powder turns into liquid molten metal, dividing the high-temperature molten metal pool 1 into a liquid phase region 1-1 and a gas phase region 1-2.

[0105] Gaseous hydrocarbons (molecular weight 16-28) are introduced into the bottom of the liquid molten metal through the raw material inlet 3 at a pressure of 4 MPa. The gaseous hydrocarbons react with the liquid metal in the form of extremely small bubbles, cracking the hydrocarbons to generate hydrogen and forming a graphene carbon layer on the metal surface to form metal carbide.

[0106] Inert gas (He, 50°C) is sprayed through the nozzles of multiple injection tubes 2-1 of gas injection device 2 toward the molten metal in liquid phase region 1-1. The gas velocity in the injection tubes of gas injection device 2 is controlled to 80 m / s, forming multiple gas columns with a width of 50 μm in the high-temperature molten metal pool 1. The inert gas flow rate is controlled so that the length of the gas columns occupies two-thirds of the height of liquid phase region 1-1.

[0107] The metal carbide comes into contact with the low-temperature inert gas column, rapidly supercooling and precipitating a thin layer of graphene (1-3 layers, 5 μm in length, 1000 nm in width). The thin graphene rapidly rises along the gas column to the gas phase region 1-2 above the high-temperature molten metal pool 1. Carried by the airflow, it exits the device through the graphene product outlet 4 of the high-temperature molten metal pool 1.

[0108] Incompletely converted hydrocarbons, hydrogen generated by cracking, and inert gases are collected in the gas phase zone 1-2 and leave the device through the mixed gas outlet 5. Part of the gas (70%) from the mixed gas outlet 5 is used for circulation operation and returned to the gas injection device 2 through the circulation pipeline for recycling.

[0109] Repeat the above steps to make the process continuous.

[0110] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0111] For simplicity of description, the method embodiments are described as a series of actions. However, those skilled in the art should be aware that the present invention is not limited by the order of the actions described, as certain steps can be performed in other orders or simultaneously according to the present invention. Furthermore, those skilled in the art should also be aware that the embodiments described in this specification are preferred embodiments, and the actions and components involved are not necessarily required for the present invention.

[0112] The above is a detailed introduction to a thin-layer graphene preparation device and method provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A thin-layer graphene preparation device, characterized in that: The device comprises: a high-temperature molten metal pool containing liquid molten metal, the high-temperature molten metal pool being divided into a liquid phase region and a gas phase region by the liquid surface of the liquid molten metal, the liquid phase region being provided with a raw material inlet; the high-temperature molten metal pool being used to crack gaseous hydrocarbons entering the liquid phase region through the raw material inlet under the action of the liquid molten metal to obtain metal carbides; A gas injection device is disposed in the gas phase region and includes a plurality of injection pipes, wherein the nozzles of the plurality of injection pipes are disposed on a side of the liquid phase region near the high-temperature molten metal pool; the gas injection device is used to inject an inert gas having a certain flow rate and flow rate into the liquid phase region through the nozzles of the plurality of injection pipes, thereby forming a plurality of gas columns with a width of 4-100 μm in the liquid phase region. The metal carbide contacts the gas columns, and is rapidly supercooled to precipitate a thin layer of graphene; The height between the pipe mouth and the liquid phase region is 0.001-0.1 times the diameter of the high-temperature molten metal pool.

2. The thin-layer graphene preparation device according to claim 1, characterized in that: The gas phase zone is further provided with a graphene product outlet and a mixed gas outlet, and the mixed gas outlet is communicated with the gas injection device for recycling the mixed gas collected in the gas phase zone through the gas injection device.

3. A method for preparing thin-layer graphene, characterized in that: The method is applicable to the thin-layer graphene preparation device according to any one of claims 1 to 2, and the method comprises: The gaseous hydrocarbons are introduced into the liquid phase of the high-temperature molten metal pool through the raw material inlet at a pressure of 1-5 MPa. The gaseous hydrocarbons are cracked under the action of the liquid molten metal to obtain metal carbides. A low-temperature inert gas with a certain flow rate and flow rate is sprayed toward the liquid phase region through the nozzles of multiple injection pipes of a gas injection device, forming multiple gas columns with a width of 4-100 μm in the liquid phase region. The metal carbide contacts the gas columns and is rapidly supercooled to precipitate a thin layer of graphene. The mixed gas collected in the gas phase region of the high-temperature molten metal pool is sent to the gas injection device through a circulation pipeline for gas recycling; The height of the gas column is 2 / 3-4 / 5 of the height of the liquid phase region.

4. The method for preparing thin-layer graphene according to claim 3, wherein The liquid molten metal is formed by melting mixed metal powder under applied voltage and current conditions. The temperature of the molten metal is 600-1400°C. The mixed metal powder is a mixture of one or more of copper, nickel, iron, molybdenum and manganese and one or more of aluminum, gallium, magnesium and tin. The particle size of the mixed metal powder is 1-100 μm.

5. The method for preparing thin-layer graphene according to claim 3, wherein: The molecular weight of the gaseous hydrocarbons is 16-300.

6. The method for preparing thin-layer graphene according to claim 3, wherein: The inert gas includes one or more of nitrogen, helium and argon.

7. The method for preparing thin-layer graphene according to claim 3 or 6, characterized in that: The temperature of the inert gas is 25-300°C; The gas flow rate of the inert gas is 30-150 m / s.

8. The method for preparing thin-layer graphene according to claim 3, wherein: The thin-layer graphene has 1-3 layers, a length of 0.5-200 μm, and a width of 2-20000 nm.

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