CN114053985A

CN114053985A - Preparation device and method of single-walled carbon nanotube

Info

Publication number: CN114053985A
Application number: CN202111322714.0A
Authority: CN
Inventors: 陈名海; 常艺; 梁晨; 袁鑫鑫; 徐乐乐; 杨劲松; 陶宇轩
Original assignee: Jiangxi Copper Technology Research Institute Co ltd
Current assignee: Jiangxi Copper Technology Research Institute Co ltd
Priority date: 2021-11-09
Filing date: 2021-11-09
Publication date: 2022-02-18

Abstract

The invention belongs to the technical field of new materials, and particularly relates to a device and a method for preparing a single-walled carbon nanotube. The preparation device comprises a catalyst evaporation cavity, a catalyst screening device, a chemical vapor deposition cavity and a gas-solid separation cavity which are connected in series; the preparation method comprises the following steps: the catalyst is evaporated by a high-temperature evaporation gun arranged in the catalyst evaporation cavity to form tiny catalyst particles, the tiny catalyst particles enter a catalyst screener under the drive of carrier gas, the size of the catalyst particles is screened by utilizing an alternate baffle structure of the screener, effective fine particles enter a chemical vapor deposition growth cavity and are combined with active carbon atoms cracked by reaction gas to generate single-walled carbon nanotubes, large-size particles are effectively removed by introducing the catalyst screener, by-products such as multi-walled carbon nanotubes and the like are prevented from entering the chemical deposition cavity by large particles, and the content and the purity of the single-walled carbon nanotubes are effectively improved. The method realizes the regulation and control of the high-quality single-wall carbon nanotube structure, can be used for continuous batch preparation, and has great commercial value.

Description

Preparation device and method of single-walled carbon nanotube

Technical Field

The invention belongs to the technical field of new materials, and particularly relates to a preparation device and a process method of a single-walled carbon nanotube.

Background

According to the theory of the growth mechanism of the single-walled carbon nanotube, the size of the catalyst is generally considered to be decisive for the growth of the single-walled carbon nanotube, so that how to obtain the catalyst with small, uniform and stable size is a prerequisite for the preparation of the single-walled carbon nanotube. In order to avoid the aggregation and growth of the catalyst particles in a high-temperature environment, an inorganic carrier can be adopted, the catalyst particles are adsorbed or filled in pores or interlayer gaps of a carrier material, and the growth of the catalyst particles is restrained through a physical space. QW Li uses light magnesium oxide as a carrier, an iron catalyst is adsorbed on the surface of the QW Li, and a conventional chemical vapor deposition method is adopted to prepare the single-wall carbon nano tube (Li Qingwen, Yan Hao, Cheng Yan, Zhang Jin, Liu Zhongfan, A scalable CVD synthesis of high purity single-walled carbon nanotubes with porous MgO as support material, J. Mater. chem., 2002, 12, 1179-1183). The Weifei team of the Qinghua university reports that vermiculite and layered double-metal hydroxide templates are used as carriers, metal iron particles are loaded in lamellar gaps, and a fluidized bed technology is used for preparing the single-walled carbon nanotube. (Meng-Qiang ZHao, Qiang Zhang, Jia-Qi Huang, sting-Qi Nie, Fei Wei, layer double hydroxide as catalysts for the effect growth of high quality single-walled Carbon nanotubes in a fluidized bed reactor, Carbon 48 (2010) 3260) 3270). The invention of Chinese patent CN201811447415.8 discloses a method for preparing single-walled carbon nanotubes by a floating chemical method, which takes diluted solution of organic metal compounds such as ferrocene and the like as a catalyst to be injected into a reactor, and is a preparation method of single-walled carbon nanotubes without carriers. However, the methods have common problems that the methods are only suitable for preparing the single-walled carbon nanotubes under the condition of low catalyst concentration, the catalyst concentration is increased, the aggregation and growth of the catalyst are often caused, and a large amount of multi-walled carbon nanotubes are formed in the product. Therefore, the efficiency and activity of the catalyst preparation become key problems restricting the scale preparation of the single-walled carbon nanotube.

The inventor discloses two methods for preparing single-wall carbon nanotubes based on the combination of high-temperature physical evaporation and chemical vapor deposition in Chinese patent inventions 201910533219.0 and 202011003243.2. The metal catalyst is evaporated into fine catalyst particles by taking high-temperature plasma arc as a high-temperature heat source, and the fine catalyst particles are combined with a cracked organic carbon source at high temperature to generate the single-walled carbon nanotube. Because the catalyst particles are prepared by high-temperature physical evaporation, the efficiency is far higher than that of the conventional high-temperature chemical decomposition process, higher preparation efficiency can be obtained, and the method is a feasible route for large-scale preparation. However, due to the very high physical evaporation efficiency, evaporated high-concentration catalyst particles collide, aggregate and grow in the transportation process, and part of the catalyst with an overlarge size is brought to a chemical vapor deposition stage, so that byproducts such as multi-wall carbon nanotubes and carbon spheres exist in the product, and the purity of the product is reduced. To improve product purity, it is necessary to screen the catalyst size to inhibit by-product production.

Disclosure of Invention

The invention mainly aims to provide a preparation device and a process method of a single-walled carbon nanotube, so as to overcome the defects in the prior art.

In order to achieve the purpose, the technical scheme adopted by the invention comprises the following steps: the device for preparing the single-walled carbon nanotube is characterized by being formed by hermetically and serially connecting a catalyst evaporation cavity, a catalyst screening device, a chemical vapor deposition cavity and a gas-solid separation cavity, and also comprising auxiliary systems such as a vacuum system, a gas circuit system, a cooling system, a circuit system and the like;

an organic carbon source mixed gas inlet is formed at the joint of the catalyst screener and the chemical vapor deposition cavity; the other end of the catalyst evaporation cavity is provided with a carrier gas inlet, and a high-temperature evaporation spray gun is arranged in the vertical direction; the catalyst screener and the chemical vapor deposition cavity are both provided with an electric heating function.

Furthermore, the catalyst evaporation cavity adopts a high-temperature physical evaporation mode, and can be plasma arc, electric spark discharge and the like; the cavity is a double-layer stainless steel water-cooling shell, the inner lining is made of heat-insulating materials, the inner wall is made of corundum, refractory bricks and the like, and the bottom is used as a high-temperature cathode and is made of graphite.

Furthermore, the catalyst screener adopts a partition plate structure which is alternately arranged in a staggered mode, high-temperature metal such as tantalum, tungsten and the like or graphite is adopted, the interlayer spacing is 5 mm-5 cm, the overlapped part of the partition plates accounts for 5-40% of the area of the partition plates, and the number of layers is at least 3.

Furthermore, the chemical vapor deposition chamber is a tube furnace, and the hearth is made of one of quartz, corundum, mullite and the like; the gas-solid separation cavity adopts the following separation modes: any one of centrifugal separation, cyclone separation and filtration separation.

Another object of the present invention is to provide a method for preparing single-walled carbon nanotubes using the above preparation system, the method specifically comprising the steps of:

s1) placing the catalyst in the catalyst evaporation cavity, starting a vacuum system to discharge air in the catalyst evaporation cavity, and starting a gas path system to switch and introduce inert gas carrier gas;

s2) starting a catalyst screener and a chemical vapor deposition chamber to heat and raise the temperature, and raising the temperature to the specified temperature;

s3) starting a high-temperature evaporation spray gun to evaporate the catalyst in the catalyst evaporation cavity, passing through a catalyst screener, and entering the chemical vapor deposition cavity along with the carrier gas;

s4) introducing organic carbon source gas mixed gas into the chemical vapor deposition cavity, leading the generated product into the gas-solid separation cavity along with the carrier gas through a connecting pipeline, and obtaining the final product after separation.

Further, the catalyst in S1) is a metal catalyst, and the metal catalyst includes any one or more of iron, cobalt, and nickel; the carrier gas is any one of nitrogen, argon and helium, and the flow rate is 5-60 liters/minute.

Further, the temperature of the catalyst screener in S2) is 500-1200 ℃, and the temperature of the chemical vapor deposition chamber is 800-1500 ℃.

Further, the high temperature evaporation lance power in said S3) is sufficient to at least partially melt the catalyst to form metal vapor.

Further, the organic carbon source gas mixture in S4) includes an organic carbon source gas, an inert carrier gas, hydrogen, and water vapor; wherein the volume of the organic carbon source gas is 5-50%; the volume of hydrogen is 10-50%, the water vapor is 0.1-5%, the rest is inert carrier gas, and the flow rate is 10-90L/min.

Further, the organic carbon source gas is one or more of methane, ethane, ethylene, ethanol, methanol, natural gas, propane and acetylene.

Compared with the prior art, the invention has the advantages that:

(1) the catalyst generated by physical evaporation passes through the catalyst screener before entering the chemical vapor deposition cavity for reaction, the large-size catalyst is subjected to barrier screening, only the small-size catalyst is reserved to enter the chemical vapor deposition cavity for reaction, the generation of byproducts such as multi-walled carbon nanotubes, carbon spheres and the like caused by the large-size catalyst is effectively eliminated, and the purity of the product is improved;

(2) the catalyst screening device adopts a staggered and alternate partition plate structure, when carrier gas carries catalyst metal smoke obtained from an evaporation cavity to enter the partition plate structure, large particles collide with the partition plate and disturb airflow, and the large particles formed by aggregation are blocked by the partition plate and cannot enter a chemical vapor deposition cavity, so that the selective screening of the catalyst particles is realized;

(3) the quantity of the catalyst entering the reaction cavity can be regulated and controlled by regulating and controlling the overlapping area, the interlayer distance and the number of layers of the partition boards and the temperature of the screening device, so that the reaction parameters can be finely regulated and controlled, and a high-quality single-walled carbon nanotube product can be obtained.

Drawings

FIG. 1 is a schematic structural diagram of an apparatus for preparing single-walled carbon nanotubes according to the present invention.

FIG. 2 is a schematic scanning electron microscope of the single-walled carbon nanotube prepared in example 5 of the present invention.

FIG. 3 is a schematic scanning electron microscope of the single-walled carbon nanotube prepared in comparative example 1 of the present invention.

FIG. 4 is a schematic diagram of thermogravimetric characterization of single-walled carbon nanotubes prepared by the apparatus of the present invention in example 5 of the present invention.

Fig. 5 is a raman spectrum of the single-walled carbon nanotube prepared in example 5 of the present invention.

Fig. 6 is a schematic view of a transmission electron microscope of the single-walled carbon nanotube prepared in example 4 of the present invention.

In the figure:

1. a reaction gas inlet; 2. a catalyst evaporation chamber; 3. a catalyst; 4. a carrier gas inlet; 5. a high temperature evaporation gun; 6. a catalyst screener, 6-1. a main body; 6-2, an upper clapboard; 6-3, a lower clapboard; 7. a chemical vapor deposition growth chamber; 8. a gas-solid separation cavity.

Detailed Description

The technical solution of the present invention is further explained with reference to the accompanying drawings and specific embodiments.

As shown in fig. 1, the present invention provides an apparatus for preparing single-walled carbon nanotubes, comprising: a catalyst evaporation cavity, a chemical vapor deposition cavity, a gas-solid separation cavity and an auxiliary unit,

wherein, catalyst evaporation chamber, chemical vapor deposition chamber and gas-solid separation chamber connect gradually, the auxiliary unit with catalyst evaporation chamber, chemical vapor deposition chamber and gas-solid separation chamber are connected, the preparation facilities still includes the catalyst screening ware, the catalyst screening ware sets up between catalyst evaporation chamber and the chemical vapor deposition chamber, just the inside of catalyst screening ware is equipped with and is used for blockking the filtration runner that screens to the catalyst.

One end of the catalyst screener is connected with the chemical vapor deposition cavity, and an organic carbon source mixed gas inlet is formed in the chemical vapor deposition cavity close to one end of the connection part;

the other end of the catalyst evaporation cavity is provided with a carrier gas inlet, and a high-temperature evaporation spray gun is arranged in the vertical direction; and the catalyst screener and the chemical vapor deposition cavity are both provided with electric heating units.

The catalyst screener comprises a main body, an upper baffle plate and a lower baffle plate,

the upper partition plates and the lower partition plates are identical in shape and size, the upper partition plates and the lower partition plates are arranged at the top and the bottom of the main body in an alternating staggered arrangement mode, the lower ends of the upper partition plates are partially overlapped with the upper ends of the lower partition plates, and the overlapped parts occupy 5-40% of the area of the partition plates;

the distance between the upper partition board and the lower partition board is 5 mm-5 cm, and the number of layers is at least 3.

The upper partition plate and the lower partition plate are both high-temperature-resistant metal plates or graphite plates, and the high-temperature-resistant metal is tantalum or tungsten.

The invention also provides a method for preparing the single-walled carbon nanotube by adopting the single-walled carbon nanotube preparation device, which comprises the following steps:

s1) placing the catalyst in the catalyst evaporation cavity, evacuating the air in the catalyst evaporation cavity, and introducing carrier gas;

s2) starting a catalyst screener and a chemical vapor deposition cavity for heating and raising the temperature to the specified temperature;

s3) starting a high-temperature evaporation spray gun to evaporate the catalyst in the catalyst evaporation cavity to form metal vapor, wherein the metal vapor flows into a filtering flow channel of the catalyst screener along with carrier gas to be filtered, and the filtered metal vapor enters the chemical vapor deposition cavity;

s4) introducing the organic carbon source gas mixed gas into the chemical vapor deposition cavity, reacting with the filtered metal vapor, introducing the generated product into the gas-solid separation cavity along with the carrier gas through the connecting pipeline, and separating to obtain the final product.

The catalyst in the S1) is a metal catalyst, and the metal catalyst is any one or more of iron, cobalt and nickel.

The carrier gas is any one of nitrogen, argon or helium, and the flow rate is 5-60 liters/minute.

The heating temperature of the catalyst screener in the S2) is 500-1200 ℃, and the heating temperature of the chemical vapor deposition cavity is 800-1500 ℃.

The organic carbon source gas mixed gas in the S4) comprises an organic carbon source gas, an inert carrier gas, hydrogen and water vapor; wherein the volume of the organic carbon source gas is 5-50%; the volume of the hydrogen is 10-50%, the water vapor is 0.1-5%, the rest is inert carrier gas, and the flow rate is 10-90L/min; the organic carbon source gas is one or more of methane, ethane, ethylene, ethanol, methanol, natural gas, propane and acetylene.

The obtained single-walled carbon nanotube has 1 TG residue not higher than 24.7% and average G/D not lower than 37.

The single-walled carbon nanotube is prepared by adopting the device.

The principle of the invention is that a catalyst screener is arranged in the middle of the device, a filtering channel is arranged in the catalyst screener, the catalyst generated by physical evaporation is firstly filtered by the catalyst screener before entering a chemical vapor deposition cavity for reaction, and the filtering channel is used for blocking and screening the large-size catalyst, only the small-size catalyst is reserved to enter the chemical vapor deposition cavity for reaction, so that the generation of byproducts such as multi-walled carbon nanotubes, carbon spheres and the like brought by the large-size catalyst is effectively eliminated, and the purity of the product is improved;

(2) the filtering channel adopts a staggered and alternate upper and lower partition plate structure, when carrier gas carries catalyst metal smoke obtained from the evaporation cavity to enter the partition plate structure, large particles collide with the partition plate and disturb airflow, the large particles formed by aggregation are blocked by the partition plate and cannot enter the chemical vapor deposition cavity, and the selective screening of the catalyst particles is realized;

meanwhile, after the partition board made of high-temperature-resistant metal and graphite is heated, the surface of the partition board becomes rough, so that large particles in the metal catalyst can be filtered more conveniently;

Example 1

After the air in the catalyst evaporation cavity 2 is exhausted, argon is supplemented; and opening the catalyst screener 6 and the chemical vapor deposition chamber 7, and respectively heating to 600 ℃ and 900 ℃.

Then evaporating the iron catalyst in the catalyst evaporation cavity 2 to obtain metal vapor by a plasma electric arc high-temperature evaporation spray gun 5, screening the evaporated iron metal vapor by a catalyst screener with the temperature of 600 ℃ by adopting argon with the flow of 15 liters/min, and feeding screened iron catalyst particles into a chemical vapor deposition cavity with the temperature of 900 ℃ along with carrier gas; meanwhile, the organic carbon source gas mixture is introduced into the chemical vapor deposition chamber 7 for growth.

And finally, the generated product enters a centrifugal separation gas-solid separation cavity along with the carrier gas through a connecting pipeline, and the final product is obtained after separation.

The catalyst screener 6 adopts a graphite material, and the graphite material is alternately staggered into a 3-layer partition structure, and the interlayer spacing is 10 mm.

The total flow rate of the organic carbon source mixed gas is 60 liters/minute, and the organic carbon source mixed gas comprises 30 volume percent of methane, 42 volume percent of hydrogen, 3 volume percent of water vapor and 25 volume percent of argon.

As is clear from Table 1, the average G/D ratio of the product obtained in example 1 was 37, and the TG residue of the product was 24.7%

Example 2

The difference between the device and the process method adopted in the embodiment 1 is that the temperature of the chemical vapor deposition chamber 7 is raised to 1250 ℃;

the high-temperature evaporation spray gun is evaporated in an electric spark discharge mode;

the catalyst screener 6 adopts a tantalum material alternately staggered 4-layer partition plate structure, and the layer spacing is 20 mm.

As is clear from Table 1, the average G/D ratio of the product obtained in example 2 was 53, and the TG residue of the product was 21.3%

Example 3

The device and the process method of the embodiment 1 are adopted, and the difference is that the temperature of the catalyst screener 6 is increased to 900 ℃; the flow rate of the argon gas is 35 liters/min, and the evaporated iron metal vapor passes through a catalyst screener with the temperature of 900 ℃ for screening.

The catalyst screener 6 adopts a graphite material alternately staggered 5-layer arrangement layer partition plate structure, and the interlayer spacing is 35 mm.

The total flow rate of the organic carbon source mixed gas is 75 liters/minute, and the organic carbon source mixed gas comprises 25% by volume of methane, 50% by volume of hydrogen, 5% by volume of water vapor and 20% by volume of argon.

It can be seen from table 1 that the average G/D ratio of the product obtained in example 3 is 79, and the TG residue of the product obtained is 12.8%, which is significantly higher than that of the product obtained in examples 1 and 2, i.e., the product obtained has higher purity and high graphitization degree.

Example 4

The difference between the device and the process method adopted in the embodiment 3 is that the catalyst screener 6 adopts a graphite material which is alternately staggered into 6 layers to arrange the layer separator structures.

The total flow rate of the organic carbon source mixed gas is 85 liters/minute, and the organic carbon source mixed gas comprises 15% by volume of methane, 50% by volume of hydrogen, 5% by volume of water vapor and 30% by volume of argon.

As can be seen from table 1, the average G/D ratio of the product was 91, and TG residue of the product was 5.44%, as can be seen from fig. 6, the product was a single-walled carbon nanotube, and the catalyst particle diameter was about 2nm and was uniform.

Example 5

The apparatus and process used in example 4 were used except that the catalyst screener 6 and the chemical vapor deposition chamber 7 were heated to 950 ℃ and 1350 ℃ respectively.

The organic carbon source gas is a mixed gas containing 10% by volume of methane and 5% by volume of ethylene.

FIG. 5 shows that the product prepared in example 5 has a distinct RBM characteristic absorption peak and a G/D ratio of 110, i.e., the product is a single-walled carbon nanotube with a high graphitization degree; from the thermogravimetric graph of the single-walled carbon nanotube prepared in example 5 of fig. 4, the residual mass is 1.44%, no obvious decomposition is seen at 400 ℃, and the purity of the single-walled carbon nanotube is high; from the scanning electron microscope of fig. 2, it can be seen that the sample of example 5 has less impurities on the surface, and further fig. 4 shows that the purity is higher. In summary, the carbon nanotubes prepared by the embodiment of the invention have the advantages of high purity and high graphitization degree.

Comparative example 1

The apparatus and process of example 5 was used with the exception that the catalyst screener 6 was not used.

It can be seen from table 1 that the TG residue of the sample of comparative example 1 was 73.4%, which is significantly higher than that of the samples of examples 1, 2, 3, 4 and 5 using the catalyst screener, and the average G/D ratio of the product was lower than 17.

FIG. 3 is a scanning electron microscope characterization of the sample prepared in comparative example 1, and compared with SEM of the product of example 5, it can be found that the sample of comparative example 1 has more impurities on the surface, further illustrating that the product has higher impurity content.

TABLE 1 comparison of material Properties of apparatus and Process for preparing Single-walled carbon nanotubes in examples and comparative examples

	Average G/D ratio	TG residual mass (%)
			Example 1	37	24.7
Example 2	53	21.3
			Example 3	79	12.8
Example 4	91	5.44
			Example 5	110	1.44
Comparative example 1	17	73.4

The apparatus and method for preparing single-walled carbon nanotubes provided in the embodiments of the present application are described in detail above. The above description of the embodiments is only for the purpose of helping to understand the method of the present application and its core ideas; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

As used in the specification and claims, certain terms are used to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. "substantially" means within an acceptable error range, and a person skilled in the art can solve the technical problem within a certain error range to substantially achieve the technical effect. The description which follows is a preferred embodiment of the present application, but is made for the purpose of illustrating the general principles of the application and not for the purpose of limiting the scope of the application. The protection scope of the present application shall be subject to the definitions of the appended claims.

It is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a good or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such good or system. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a commodity or system that includes the element.

It should be understood that the term "and/or" as used herein is merely one type of association that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

The foregoing description shows and describes several preferred embodiments of the present application, but as aforementioned, it is to be understood that the application is not limited to the forms disclosed herein, but is not to be construed as excluding other embodiments and is capable of use in various other combinations, modifications, and environments and is capable of changes within the scope of the application as described herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the application, which is to be protected by the claims appended hereto.

Claims

1. An apparatus for preparing single-walled carbon nanotubes, the apparatus comprising: a catalyst evaporation cavity, a chemical vapor deposition cavity, a gas-solid separation cavity and an auxiliary unit,

wherein, catalyst evaporation chamber, chemical vapor deposition chamber and gas-solid separation chamber connect gradually, the auxiliary unit with catalyst evaporation chamber, chemical vapor deposition chamber and gas-solid separation chamber are connected, its characterized in that, the preparation facilities still includes the catalyst screening ware, the catalyst screening ware sets up between catalyst evaporation chamber and the chemical vapor deposition chamber, just the inside of catalyst screening ware is equipped with and is used for blockking the filtration runner of screening to the catalyst.

2. The preparation device of claim 1, wherein one end of the catalyst screener is connected with the chemical vapor deposition chamber, and an organic carbon source mixed gas inlet is arranged on the chemical vapor deposition chamber close to one end of the connection;

3. The manufacturing apparatus according to claim 1, wherein the catalyst screener includes a main body, an upper partition, a lower partition, and a heating unit,

the upper partition plates and the lower partition plates are arranged at the top and the bottom of the main body in an alternating staggered arrangement mode, the lower ends of the upper partition plates are partially overlapped with the upper ends of the lower partition plates, the sizes of the upper partition plates and the lower partition plates are the same, and the overlapped parts occupy 5-40% of the areas of the partition plates;

the distance between the upper partition board and the lower partition board is 5 mm-5 cm, and the number of layers is at least 3;

the heating unit is disposed on a sidewall of the main body.

4. The manufacturing apparatus as set forth in claim 3, wherein the upper and lower separators are each a high-temperature-resistant metal plate or a graphite plate.

5. A method for preparing single-walled carbon nanotubes using the single-walled carbon nanotube preparation apparatus of any one of claims 1 to 4, wherein: the method specifically comprises the following steps:

6. The method of claim 5, wherein: the catalyst in the S1) is a metal catalyst.

7. The method of claim 5, wherein: the carrier gas is any one of nitrogen, argon or helium, and the flow rate is 5-60 liters/minute.

8. The method of claim 5, wherein: the heating temperature of the catalyst screener in the S2) is 500-1200 ℃, and the heating temperature of the chemical vapor deposition cavity is 800-1500 ℃.

9. The method of claim 5, wherein: the organic carbon source gas mixed gas in the S4) comprises an organic carbon source gas, an inert carrier gas, hydrogen and water vapor; wherein the volume of the organic carbon source gas is 5-50%; 10-50% of hydrogen volume, 0.1-5% of water vapor and the balance of inert carrier gas; and the flow rate of the organic carbon source gas mixed gas is 10-90 liters/minute.

10. A single-walled carbon nanotube produced by the method according to any one of claims 5 to 9.