A method for preparing and collecting graphene

Abstract

The present invention relates to a method for preparing and collecting graphene, which comprises the following steps: S1, introducing a first carbon source gas into a liquid metal catalyst under the protection of a first carrier gas, and decomposing and growing graphene at high temperature; the liquid metal catalyst is a liquid transition metal catalyst; S2, controllably introducing a jet gas flow, while contacting the liquid metal catalyst, promptly bringing out the grown graphene, and collecting the graphene; the jet gas flow is a second carbon source gas and / or a second carrier gas. The present invention can effectively control the size and number of layers of graphene, and at the same time, the introduced jet gas flow brings out the grown graphene in time, and collects the graphene powder product in a collecting device. The method and system for preparing and collecting graphene of the present invention can continuously obtain high-quality graphene products.

Description

Technical Field

[0001] The invention belongs to the field of nano material preparation, and in particular relates to a method and system for preparing and collecting graphene. Background Art

[0002] Graphene is a wonderful carbon nanomaterial with several single atomic layers of two-dimensional crystal structure and many excellent properties. It has been attracting the attention of researchers in the past decade. Graphene with different numbers of layers and / or different particle sizes exhibits different properties and thus has different applications.

[0003] Synthesizing graphene with controllable layers is of great significance for both basic research and practical applications. Many researchers have been committed to improving the uniformity of graphene, especially obtaining uniform single-layer graphene. Among them, the preparation of graphene by chemical vapor deposition (CVD) has attracted widespread attention due to its controllable number of layers, high quality and few defects. The traditional chemical vapor deposition method involves multiple steps such as substrate preparation, two-dimensional material growth, separation from the catalyst and transfer to the target substrate. Due to the natural defects on the solid surface and the separation and transfer steps during the production process, the preparation of high-quality graphene has become a challenge.

[0004] The bubbling CVD method using liquid metal as a catalyst can directly prepare graphene powder without considering the substrate transfer problem, and has gradually received some attention in recent years. The existing bubbling CVD method generally uses methane-containing gas as raw material and molten liquid metal as catalyst; methane and inert gas enter the reactor through the air inlet, and the gas passes through the molten metal in the form of bubbles. Methane is decomposed into carbon atoms and hydrogen atoms under the catalytic action of the molten metal, and the carbon atoms aggregate and combine to form graphene. However, this method currently has the problem of graphene aggregating and further growing on the surface of the liquid metal, which affects the product quality and product collection. Summary of the invention

[0005] In order to solve the technical problems existing in the above-mentioned prior art, the present invention provides a method and system for preparing and collecting graphene. Through the preparation method and system of the present invention, the size and number of layers of graphene can be effectively controlled, and the product can be easily collected, which is conducive to high-quality, continuous large-scale production of graphene.

[0006] The present invention provides a method for preparing and collecting graphene, comprising the following steps:

[0007] S1, passing a first carbon source gas into a liquid metal catalyst under the protection of a first carrier gas, and decomposing and growing graphene at high temperature; the liquid metal catalyst is a liquid transition metal catalyst;

[0008] S2. Controllably introduce a jet gas flow to bring the grown graphene out in time while contacting the liquid metal catalyst, and collect the graphene; the jet gas flow is a second carbon source gas and / or a second carrier gas.

[0009] Preferably, the first carbon source gas and the second carbon source gas respectively include one or more of methane, ethane, ethylene, acetylene, carbon monoxide, carbon dioxide, ethanol, propylene, propane, butane, butadiene, pentane, pentene, benzene and toluene.

[0010] Preferably, the first carrier gas and the second carrier gas respectively include one or more of hydrogen, nitrogen, argon and helium.

[0011] Preferably, the method further comprises: injecting the tail gas after high-temperature decomposition and growth of graphene into the liquid metal catalyst in the form of airflow.

[0012] Preferably, the jet airflow is a periodic jet airflow; the periodic interval time of the controllably introducing the jet airflow is 1 min-2 h, preferably 10 min-50 min.

[0013] Preferably, the flow rate of the jet gas flow is 1-20 times the total flow rate of the first carbon source gas and the first carrier gas.

[0014] The present invention provides a system for preparing and collecting graphene, comprising:

[0015] A reaction device with a liquid metal catalyst inside; the reaction device is provided with a plurality of gas inlets for introducing reaction gas and jet gas flow; the liquid metal catalyst is a liquid transition metal catalyst; the reaction gas includes a first carbon source gas and a first carrier gas, and the jet gas flow is a second carbon source gas and / or a second carrier gas; the reaction device has a heat preservation function, so that the first carbon source gas is decomposed at high temperature under the action of the liquid metal catalyst to grow graphene, and the jet gas flow takes out the grown graphene in time;

[0016] The material collecting device connected to the reaction device is used to collect the grown graphene.

[0017] Preferably, the gas inlet for introducing the reaction gas is located at the bottom, top or side of the reaction device; the gas inlet for the jet gas flow and the reaction gas are the same or different.

[0018] Preferably, the system further comprises: a gas recovery device connected to the material collecting device, for recovering tail gas after high temperature decomposition and growth of graphene.

[0019] Preferably, the system further comprises: a gas exhaust device connected to the material collecting device, for exhausting tail gas after high temperature decomposition and growth of graphene.

[0020] Compared with the prior art, the technical solution of the embodiment of the present invention first passes the mixed gas of the first carbon source gas and the first carrier gas into a reaction device equipped with a liquid metal catalyst (liquid transition metal catalyst) to decompose and grow graphene at high temperature; then a jet gas flow is controllably introduced to contact the liquid metal catalyst, and the time interval and / or flow rate of the jet gas flow are controlled to prevent the graphene from aggregating and overgrowing on the surface of the liquid metal catalyst, thereby effectively controlling the size and number of layers of the graphene. At the same time, the jet gas flow takes out the grown graphene in time, and the graphene powder product is collected in the collecting device. The method and system for preparing and collecting graphene of the present invention can continuously obtain high-quality graphene products. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 A flow chart of a method for preparing and collecting graphene according to some embodiments of the present invention;

[0023] Figure 2 A schematic diagram of a system structure for preparing and collecting graphene in some embodiments of the present invention;

[0024] Figure 3 This is an AFM image of the graphene powder product obtained in Example 1;

[0025] Figure 4 This is an AFM image of the graphene powder product obtained in Example 2;

[0026] Figure 5 This is an AFM image of the graphene powder product obtained in Example 3;

[0027] Figure 6 This is an AFM image of the graphene powder product obtained in Example 4;

[0028] Figure 7 This is an AFM image of the graphene powder product obtained in Example 5;

[0029] Figure 8 This is the AFM image of the graphene powder product obtained in Comparative Example 1;

[0030] Fig. 9 This is the AFM image of the graphene powder product obtained in Comparative Example 2;

[0031] Figure 2In the figure, 1 is a reaction device; 2 is a liquid metal catalyst; 3 is a plurality of gas inlets, including a first gas inlet 4a, a second gas inlet 4b, a third gas inlet 4c, and a fourth gas inlet 4d; 5 is a material receiving device, and 6 is a gas recovery device (the recovery connection relationship is not shown), and the gas recovery device can also be replaced by a gas discharge device. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with embodiments. Unless otherwise defined, all professional terms used hereinafter have the same meaning as those skilled in the art generally understand. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0033] The present invention provides a method for preparing and collecting graphene, comprising the following steps:

[0034] S1, passing a first carbon source gas into a liquid metal catalyst under the protection of a first carrier gas, and decomposing and growing graphene at high temperature; the liquid metal catalyst is a liquid transition metal catalyst;

[0035] S2. Controllably introduce a jet gas flow to bring the grown graphene out in time while contacting the liquid metal catalyst, and collect the graphene; the jet gas flow is a second carbon source gas and / or a second carrier gas.

[0036] Accordingly, the present invention provides a system for preparing and collecting graphene, comprising:

[0037] A reaction device with a liquid metal catalyst inside; the reaction device is provided with a plurality of gas inlets for introducing reaction gas and jet gas flow; the liquid metal catalyst is a liquid transition metal catalyst; the reaction gas includes a first carbon source gas and a first carrier gas, and the jet gas flow is a second carbon source gas and / or a second carrier gas; the reaction device has a heat preservation function, so that the first carbon source gas is decomposed at high temperature under the action of the liquid metal catalyst to grow graphene, and the jet gas flow takes out the grown graphene in time;

[0038] The material collecting device connected to the reaction device is used to collect the grown graphene.

[0039] See also Figure 1 and Figure 2 , Figure 1 Shown is a flow chart of a method for preparing and collecting graphene, Figure 2It is a schematic diagram of the system structure of an embodiment; the method comprises the following steps: S1: introducing a mixture of carbon-containing gas and carrier gas into a reactor filled with a liquid metal catalyst; S2: taking out graphene powder by airflow injection; by controlling the time of airflow injection, graphene is prevented from aggregating and further growing on the surface of liquid metal, and the size and number of layers of graphene can be effectively controlled, which is conducive to high-quality, continuous and large-scale production of graphene.

[0040] In the embodiment of the present invention, a solid transition metal catalyst can be placed in a reaction device 1 of a preparation system, preferably evacuated to exhaust air or passed with inert gas protection, and heated until the solid transition metal catalyst is melted into a liquid metal catalyst 2, and the heating temperature is in the range of 400-2000°C, such as 1000°C, 1300°C, 1400°C, 1600°C, etc. In the present invention, the liquid metal catalyst is a liquid transition metal catalyst, and the transition metal catalyst includes but is not limited to at least one of titanium, chromium, manganese, iron, cobalt, nickel, copper, zinc, palladium, silver, platinum, and gold, such as a copper-nickel alloy catalyst.

[0041] In the system for preparing and collecting graphene in the embodiments of the present invention, the reaction device 1 is a reaction vessel provided with a plurality of gas inlets, which has a closed cavity, contains a liquid metal catalyst, and can be kept warm for catalytic reaction; it can be a conventional reaction furnace erected vertically. Specifically, the reaction furnace in some embodiments of the present invention is heated by an induction coil, kept warm by a graphite furnace and a heat-insulating material, and measured by a thermocouple.

[0042] In the above-mentioned reaction device 1 with the liquid metal catalyst 2 installed therein, step S1 of the embodiment of the present invention introduces a mixture of the first carbon source gas and the first carrier gas through the first gas inlet 4a and / or the third gas inlet 4c, so that the carbon source gas is decomposed at high temperature to grow graphene under the catalysis of the contacting liquid metal catalyst.

[0043] Wherein, the first carbon source gas preferably includes one or more of methane, ethane, ethylene, acetylene, carbon monoxide, carbon dioxide, ethanol, propylene, propane, butane, butadiene, pentane, pentene, benzene and toluene, and can further be methane; the first carrier gas is an inert gas that can carry and protect the carbon-containing reaction gas, preferably including one or more of hydrogen, nitrogen, argon and helium, and specifically nitrogen can be used. The first air inlet 4a and the third air inlet 4c are located at the bottom of the reaction device 1, and can also be located at the top or the side, preferably uniformly arranged; the mixed gas of the first carbon source gas and the first carrier gas introduced contacts the liquid metal catalyst, and the flow rate of the mixed gas is preferably 0.5~2.5 Nm 3 / h, further 0.5~1.8 Nm 3 / h, the carbon source gas content in the mixed gas is 0.5%~8%, mainly introduced in the form of bubbling, and the inlet temperature of the mixed gas is room temperature (10-30℃). Usually, the inside of the reaction device 1 is slightly positive pressure (pressure 0-0.09Mpa), and the gas flow rate is 0.01-1m / s; the temperature of the specific reactor is a fixed value, which is used for heating and melting the catalyst and decomposing the carbon source gas. The carbon source gas decomposes and grows to form graphene after passing through the high-temperature molten metal.

[0044] At this time, it is preferred to periodically introduce a jet gas flow from the second air inlet 4b and / or the fourth air inlet 4d above the liquid surface, and the jet gas flow is the second carbon source gas and / or the second carrier gas; the first air inlet 4a, the second air inlet 4b, the third air inlet 4c and the fourth air inlet 4d belong to the gas inlet 3, and the second air inlet 4b and the fourth air inlet 4d can be introduced into the jet gas flow separately, and the air inlet position is the bottom, top or side of the reaction device 1, and can be selected to be introduced into the liquid metal catalyst or flow through the surface of the liquid metal catalyst, or can be combined with the first air inlet 4a or the third air inlet 4c to form the same gas inlet. In addition, the number of the second air inlet 4b and the fourth air inlet 4d is one or more, and there is no special restriction in this application, and multiple second air inlets or fourth air inlets can be evenly distributed. In some embodiments, the reaction furnace intake can be inserted into the reaction furnace (the first air inlet 4a) through the air inlet pipe or directly ventilated from the bottom of the reaction furnace (the third air inlet 4c).

[0045] The jet gas flow described in the embodiment of the present invention is a gas fluid with a certain flow rate formed by a controllable jet process, which contacts the liquid metal catalyst. By controlling the time interval and / or flow rate of the jet gas flow, the size and number of layers of the graphene are controlled, and the grown graphene is taken out in time to avoid further reaction, thereby collecting the graphene powder in the collecting device 5.

[0046] Specifically, the second carbon source gas includes one or more of methane, ethane, ethylene, acetylene, carbon monoxide, carbon dioxide, ethanol, propylene, propane, butane, butadiene, pentane, pentene, benzene and toluene, preferably the same type as the first carbon source gas; the second carrier gas includes one or more of hydrogen, nitrogen, argon and helium, preferably nitrogen. In step S2 of the embodiment of the present invention, the jet gas flow can be introduced periodically or non-periodically, preferably the jet gas flow is introduced periodically. The controllable introduction of the jet gas flow is a periodic injection, and the periodic time interval is preferably 1min-2h, and further preferably 10min-50min. In addition, the flow rate of the jet gas flow is preferably 1-20 times the total flow rate of the first carbon source gas and the first carrier gas mixture; in some embodiments, the flow rate of the jet gas flow may be 0.5~50 Nm 3 / h, further 0.5~30 Nm 3 / h, or 0.7~20 Nm 3 / h, 0.7~10 Nm 3 / h, etc., and the temperature of the jet gas flow is 0-700℃. A fixed product quality can be obtained according to the time interval of the jet gas; the injection cycle and speed of the jet gas flow will affect the product quality. The grown graphene has a low density and can be carried out by increasing the jet gas flow; if it is not carried out in time, the high temperature inside the reactor and the continued contact with the surface of the liquid metal catalyst will affect the quality of the graphene.

[0047] In an embodiment of the present invention, the graphene powder brought out is collected by a material collecting device 5, and the tail gas after the reaction is recovered by a gas recovery device 6, and the recovered tail gas can also be used for the jet gas flow in the above step. The feed end of the material collecting device 5 is connected to the reaction device 1, located at one end of the tail gas outlet of the reaction gas, and its gas outlet end is connected to the gas recovery device 6, without specific position requirements. In other embodiments, the gas recovery device 6 can be replaced by a gas discharge device to directly discharge the tail gas after the reaction.

[0048] Through the above-mentioned method and system for preparing and collecting graphene in the embodiment of the present invention, the size and number of layers of graphene can be effectively controlled, and the product can be easily collected, which is conducive to high-quality, continuous large-scale production of graphene.

[0049] In order to better illustrate the present invention, the following examples are further illustrated. Unless otherwise specified, the various reagents and raw materials used in the present invention are all commercially available products or products prepared by known methods. Among them, the reaction furnace is heated by an induction coil, and is insulated by a graphite furnace and a heat-insulating material, and the temperature is measured by a thermocouple.

[0050] Example 1

[0051] Put the solid copper-nickel alloy catalyst (purity not less than 99.9%) into the reaction furnace, evacuate the air, and heat to 1500℃ until the catalyst melts.

[0052] Inside the reaction furnace (furnace temperature at 1500-1600°C), a mixture of methane and nitrogen (methane volume content of 3-5%) is directly bubbled in from the bottom of the reaction furnace (third gas inlet 4c) at a flow rate of 0.7 Nm 3 / h; at this time, nitrogen is periodically injected from above the liquid surface at intervals of 120 minutes (1 inlet, the fourth inlet 4d is distributed on the top of the reactor, the temperature is 100°C), with a flow rate of 1.6 Nm 3 / h. The graphene powder is collected by the collecting device. The collected products are tested by atomic force microscopy, such as Figure 3As shown, the powder layer obtained at this time is relatively thick, about 8-12 layers. At the same time, the particle size results show that the particle size of graphene is relatively large at this time, reaching about D50=100 microns.

[0053] Example 2

[0054] Put the solid copper-nickel alloy catalyst (purity not less than 99.9%) into the reaction furnace, evacuate the air, and heat to 1500℃ until the catalyst melts;

[0055] Inside the reaction furnace (furnace temperature at 1500-1600°C), a mixture of methane and nitrogen (methane volume content of 5-7%) is introduced from the bottom of the reaction furnace through the inlet pipe (first inlet 4a) inserted into the reaction furnace, with a flow rate of 0.7Nm 3 / h; at this time, nitrogen is injected from above the liquid surface periodically at intervals of 15 minutes (1 air inlet, the second air inlet 4b is distributed on the side of the reactor, the temperature is 25°C), with a flow rate of 1.6 Nm 3 / h. The graphene powder is collected by the collecting device. Figure 4 At this time, the number of powder layers obtained is 1-2. At the same time, the particle size results show that the particle size of graphene is relatively large, reaching about D50=35 microns.

[0056] Example 3

[0057] Put the solid copper-nickel alloy catalyst (purity not less than 99.9%) into the reaction furnace, evacuate the air, and heat to 1500℃ until the catalyst melts;

[0058] Inside the reactor (furnace temperature at 1500-1600°C), a mixture of methane and nitrogen (methane volume content of 5-7%) is bubbled directly from the bottom of the reactor at a flow rate of 0.7 Nm 3 / h; at this time, nitrogen is injected periodically from above the liquid surface at intervals of 60 minutes (1 air inlet, the second air inlet 4b is distributed on the side of the reactor, the temperature is 25°C), with a flow rate of 0.7Nm 3 / h. The graphene powder is collected by the collecting device. Figure 5 At this time, the number of powder layers obtained is 6-10. At the same time, the particle size results show that the particle size of graphene is relatively large, reaching about D50=78 microns.

[0059] Example 4

[0060] Put the solid copper catalyst (purity not less than 99.9%) into the reaction furnace, evacuate the air, and heat to 1500℃ until the catalyst melts;

[0061] Inside the reactor (furnace temperature is 1500-1600℃), a mixture of methane and nitrogen (methane volume content is 5-7%) is introduced from the bottom of the reactor through an inlet pipe inserted into the reactor, with a flow rate of 0.7 Nm 3 / h; at this time, hydrogen is periodically injected from above the liquid surface at intervals of 20 minutes (1 air inlet, the second air inlet 4b is distributed on the side of the reactor, the temperature is 25°C), with a flow rate of 1.6 Nm 3 / h. The graphene powder is collected by the collecting device. Figure 6 At this time, the number of powder layers obtained is 2-4. At the same time, the particle size results show that the particle size of graphene is relatively large, reaching about D50=40 microns.

[0062] Example 5

[0063] Put the solid copper-nickel alloy catalyst (purity not less than 99.9%) into the reaction furnace, evacuate the air, and heat to 1500℃ until the catalyst melts;

[0064] Inside the reactor (furnace temperature is 1500-1600℃), a mixture of methane and nitrogen (methane volume content is 2-5%) is introduced from the bottom of the reactor through an inlet pipe inserted into the reactor, with a flow rate of 0.5 Nm 3 / h; at this time, the tail gas after the reaction is periodically injected at intervals of 1min (the tail gas is mainly composed of nitrogen, 1 air inlet, the second air inlet 4b is distributed on the side of the reactor, the temperature is 400℃), the flow rate is 10 Nm 3 / h. The graphene powder is collected by the collecting device. Figure 7 At this time, the number of powder layers obtained is 3-5. At the same time, the particle size results show that the particle size of graphene is relatively small, reaching about D50=10 microns.

[0065] Comparative Example 1

[0066] Put the solid copper-nickel alloy catalyst into the reaction furnace, evacuate the air, and heat to 1500°C until the catalyst melts;

[0067] Inside the reactor (furnace temperature is 1500-1600℃), a mixture of methane and nitrogen (methane volume content is 3-5%) is directly introduced from the bottom of the reactor at a flow rate of 0.7 Nm 3 / h; no jet airflow is introduced at this time. The powder is collected by the collecting device. The collected product is tested by atomic force microscopy, such as Figure 8 At this time, the number of layers of the powder obtained is relatively thick, about 18-30 layers. At the same time, the particle size results show that the particle size of graphene is relatively large at this time, reaching about D50=150 microns.

[0068] Comparative Example 2

[0069] Put the solid copper catalyst into the reaction furnace, evacuate the air, and heat to 1500℃ until the catalyst melts;

[0070] Inside the reactor (furnace temperature is 1500-1600℃), a mixture of methane and nitrogen (methane volume content is 3-5%) is directly introduced from the bottom of the reactor at a flow rate of 0.7 Nm 3 / h; When the graphene powder is accumulated to a height of 10-20cm from the molten metal catalyst liquid level, air is blown from the second air inlet 4b on the side of the reactor. The powder is collected by the collecting device. The collected product is tested by atomic force microscopy, such as Fig. 9 At this time, the number of layers of the powder obtained is relatively thick, about 20-30 layers. At the same time, the particle size results show that the particle size of graphene is relatively large at this time, which can reach about D50=200 microns. If the graphene powder is piled up to a certain height, the number of layers of graphene is relatively thick and the particle size is relatively large.

[0071] As can be seen from the above embodiments, the embodiments of the present invention first pass the mixed gas of the first carbon source gas and the first carrier gas into a reaction device equipped with a liquid metal catalyst to decompose and grow graphene at high temperature; then controllably pass a jet gas flow into contact with the liquid metal catalyst, and by controlling the time interval and / or flow rate of the jet gas flow, graphene is prevented from aggregating and overgrowing on the surface of the liquid metal catalyst, and the size and number of layers of graphene can be effectively controlled. At the same time, the jet gas flow takes out the grown graphene in time, and continuously collects it in the receiving device, so that a high-quality graphene powder product can be obtained, which is conducive to high-quality, continuous and large-scale production of graphene.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing and collecting graphene, characterized in that: The following steps are involved: S1, passing a first carbon source gas into the interior or surface of a liquid metal catalyst under the protection of a first carrier gas, and decomposing and growing graphene at high temperature; the liquid metal catalyst is a liquid transition metal catalyst; S2, periodically introduce a jet gas flow, regulate the growth time of graphene by controlling the gas flow injection time, and take out the grown graphene to collect graphene with controllable quality and size; the jet gas flow is a second carbon source gas and / or a second carrier gas; the first carrier gas and the second carrier gas respectively include one or more of hydrogen, nitrogen, argon and helium; the jet gas flow is a periodic jet gas flow; the periodic interval time of the periodic introduction of the jet gas flow is 1min-2h; the flow rate of the jet gas flow is 1-20 times the total flow rate of the first carbon source gas and the first carrier gas; the gas inlet for introducing the reaction gas is located at the bottom, top or side of the reaction device, and a mixed gas of the first carbon source gas and the first carrier gas is introduced, and the carbon source gas content in the mixed gas is 0.5% to 8%; the gas inlet of the jet gas flow is located at the side of the reaction device, and is different from the gas inlet of the reaction gas; The system used in the method includes: A reaction device with a liquid metal catalyst inside; the reaction device is provided with a plurality of gas inlets for introducing reaction gas and jet gas flow; the reaction gas includes a first carbon source gas and a first carrier gas, the reaction device has a heat preservation function, and the inside of the reaction device is slightly positively pressurized, with a pressure of 0-0.09MPa, so that the first carbon source gas is decomposed at high temperature under the action of the liquid metal catalyst to grow graphene; The collecting device connected to the reaction device is used to collect the grown graphene.

2. The method for preparing and collecting graphene according to claim 1, characterized in that: The first carbon source gas and the second carbon source gas respectively include one or more of methane, ethane, ethylene, acetylene, carbon monoxide, carbon dioxide, ethanol, propylene, propane, butane, butadiene, pentane, pentene, benzene and toluene.

3. The method for preparing and collecting graphene according to any one of claims 1 to 2, characterized in that: The method further comprises: injecting the tail gas after high-temperature decomposition and growth of graphene into the liquid metal catalyst in the form of air flow.

4. The method according to claim 1, characterized in that The system also includes: a gas recovery device connected to the material collecting device, which is used to recover the tail gas after high-temperature decomposition and growth of graphene.

5. The method according to claim 1, characterized in that: The system also includes: a gas exhaust device connected to the material collecting device, which is used to exhaust the tail gas after the high-temperature decomposition and growth of graphene.

Images