Continuous and stable preparation device and method for single-walled carbon nanotubes

Abstract

The invention discloses a continuous and stable preparation device and method for a single-walled carbon nanotube, and relates to the technical field of nanocarbon material preparation, the continuous and stable preparation device for the single-walled carbon nanotube structurally comprises hollow graphite, a graphite crucible, a plasma electric arc furnace body, an air inlet and a discharge port, the hollow graphite serves as a cathode of the plasma electric arc furnace, and the graphite crucible serves as an anode of the plasma electric arc furnace. The plasma arc is initiated between the graphite electrodes, so that the plasma high-temperature evaporation catalyst is fully utilized, the defect of arc striking of a graphite cathode and a liquid catalyst anode in a conventional method is avoided, the evaporation rate of the catalyst is reduced, and the problem of arc breaking caused by metal droplet sputtering and coking in the liquid electrodes is solved; a series of defects of a conventional scheme are avoided through the convex crucible anode, so that the continuous stability of the reaction is greatly improved, and stable and continuous preparation of the single-walled carbon nanotube is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of nanocarbon materials, and specifically provides a continuous and stable preparation device and method for single-walled carbon nanotubes. Background Art

[0002] Single-walled carbon nanotubes are one-dimensional tubular nanomaterials formed by curling a single layer of graphene sheets. Their diameters are usually 0.4 to 2 nanometers, and their lengths can reach several micrometers or even longer. Their structure can be regarded as a seamless connection of a honeycomb network composed of hexagonal carbon rings to form a cylinder. Depending on the curling method (chirality), single-walled carbon nanotubes can exhibit metallic or semiconducting properties. This unique structure endows single-walled carbon nanotubes with excellent physical and chemical properties and shows broad application prospects in multiple fields. In the field of electronic devices, their high conductivity and semiconducting properties make them ideal materials for field-effect transistors, sensors, and flexible electrodes. In the energy field, single-walled carbon nanotubes are used as electrode materials for lithium-ion batteries, supercapacitors, and solar cells to improve energy density and charge-discharge efficiency. In the field of composite materials, their high strength and light weight can be used to reinforce polymer, metal, or ceramic matrices, improving the mechanical properties and functionality of the materials. In addition, single-walled carbon nanotubes also have important applications in the biomedical field, such as drug carriers, biosensors, and photothermal conversion agents in tumor treatment.

[0003] The preparation methods of single-walled carbon nanotubes mainly include arc discharge method, laser evaporation method, and chemical vapor deposition method (CVD). The arc discharge method generates high temperature by discharging in an inert gas, causing the graphite electrode to evaporate and form single-walled carbon nanotubes; the laser evaporation method uses a high-energy laser beam to bombard a graphite target containing a metal catalyst to generate single-walled carbon nanotubes. These two methods are usually used for laboratory research, but the yield is low. The chemical vapor deposition method is the most commonly used large-scale preparation method at present. Single-walled carbon nanotubes are grown on the surface of a catalyst (such as iron, cobalt, or nickel) by decomposing carbon-containing gases (such as methane or ethylene) at high temperature. The CVD method has the advantages of low cost, high controllability, and suitability for large-scale production, and is an important method for industrial preparation of single-walled carbon nanotubes. Although single-walled carbon nanotubes still face challenges such as purity, chirality control, and dispersibility during the preparation process, their unique properties and broad application prospects make them one of the hotspots in nanomaterial research. However, balancing efficiency and quality is still the key problem in the large-scale preparation and application of single-walled carbon nanotubes, and the development of new and efficient preparation equipment and methods is still the focus of current research.

[0004] Chinese invention patent CN 201910533219.0 is a preparation method for single-walled carbon nanotubes. It uses a plasma arc to evaporate a catalyst metal to prepare a catalyst, and at the same time introduces a carbon source gas. The high-temperature plasma simultaneously realizes the high-temperature evaporation of the metal to prepare the catalyst and the cracking of the organic carbon source, and directly prepares single-walled carbon nanotubes.

[0005] Chinese Invention Patent CN202111322714.0 can partially solve the current problem by attempting to isolate the catalyst evaporation chamber and the growth chamber. However, the simple division method will cause the catalyst to aggregate and grow during transportation, resulting in failure. At the same time, it also reduces the thermal energy utilization rate, leading to a decrease in yield and an increase in preparation cost.

[0006] Chinese Invention Patent 202210608795.9 utilizes the high-temperature zone formed by the arc confined in a deep graphite crucible to obtain a higher reaction temperature and a longer reaction residence time. At the same time, by utilizing the activation effect of arc plasma, single-walled carbon nanotubes with high crystallinity can be prepared. Summary of the Invention

[0007] The biggest drawback of the above methods is the excessive evaporation of the catalyst, as well as the problems of catalyst condensation and carbon nanotube product coking formed between the electrodes, which will cause the cathode and anode to short-circuit, resulting in arc interruption, and thus a sharp decline in arc stability, making it difficult to achieve stable and continuous preparation. Therefore, overcoming the problem of arc interruption caused by short-circuit is a problem that must be overcome to ensure the stability of product quality.

[0008] In view of the above problems, the present invention provides the following technical solutions:

[0009] On the one hand, the present invention provides a device for continuously and stably preparing single-walled carbon nanotubes. The structure of the device includes a hollow graphite, a graphite crucible, a plasma arc furnace body, an air inlet, and a discharge outlet. Among them, the hollow graphite serves as the cathode of the plasma arc furnace, and the graphite crucible serves as the anode of the plasma arc furnace.

[0010] The graphite crucible is a structure with a protruding middle part for containing a metal catalyst.

[0011] The graphite crucible is arranged at the bottom of the device, and the hollow graphite is arranged directly above the graphite crucible.

[0012] The diameter of the protruding middle part of the graphite crucible is equivalent to the diameter of the hollow graphite.

[0013] Furthermore, the protruding middle part of the graphite crucible (1) is 2-20 cm higher than the liquid level of the contained metal catalyst.

[0014] The power of the power supply of the plasma arc furnace is 20-1000 kW, the current is 100-10000 A, and the voltage is 10-500 V.

[0015] On the other hand, the present invention provides a method for continuously preparing single-walled carbon nanotubes stably, which is characterized in that, in this method, an arc is struck between the hollow graphite (4) and the protruding part of the graphite crucible (1), the first catalyst placed in the graphite crucible (1) is heated and melted by a plasma arc, and the temperature of the furnace chamber of the furnace body (3) is raised to a specified temperature; at this time, a carbon source gas mixture and a second catalyst component are introduced into the furnace body (3), a single-walled carbon nanotube product is obtained through a high-temperature chemical reaction, and then it is discharged from the furnace body (3) through the discharge port (5), and the single-walled carbon nanotube product is collected.

[0016] Furthermore, the method specifically includes the following steps:

[0017] S1) Place the first catalyst in the graphite crucible (1);

[0018] S2) Introduce a plasma gas, turn on the plasma power supply, generate a plasma arc between the anode and the cathode, melt the first catalyst in the graphite crucible (1) until the temperature of the furnace chamber rises to the specified temperature;

[0019] S3) After mixing the carbon source gas and the carrier gas, carry the second catalyst into the furnace body (3) through the hollow graphite cathode (4), and the product is purged out of the furnace body (3) by introducing an inert gas through the intake port (2), and the single-walled carbon nanotube product is continuously collected.

[0020] Furthermore, in the step S1), the first catalyst is iron, cobalt, nickel metal or a mixture thereof.

[0021] Furthermore, in the step S1), the first catalyst is an alloy or a mixture of iron, cobalt, nickel and refractory metals, wherein the refractory metal element is molybdenum, tungsten, tantalum, niobium, hafnium or zirconium, and the weight ratio content of the refractory metal element is 20-60%.

[0022] Furthermore, in the step S2), the arc gas is any one, two or more kinds of mixed gases of argon, nitrogen, helium, hydrogen, water vapor, and the flow rate is 10 L / min to 500 L / min;

[0023] The specified temperature of the furnace chamber is 900-1500 °C.

[0024] Furthermore, in the step S3), the carbon source gas is any one of methane, ethylene, acetylene, propylene, propane;

[0025] The carrier gas is a mixture of nitrogen, argon or helium and hydrogen, wherein the volume of the carbon source gas is 10-80%; the volume of hydrogen is 0-35%, and the rest is an inert gas, and the flow rate is 10 L / min to 200 L / min.

[0026] Further, in the step S3), the second catalyst is a mixed powder of 50-95% metal powder and 5-50% promoter;

[0027] The metal powder is any one or combination of iron, cobalt, and nickel, and the particle size is 50-350 mesh;

[0028] The promoter is any one or mixture thereof such as sulfur powder, selenium powder, iron sulfide, ferrous sulfide, nickel sulfide, cobalt sulfide, etc., and the particle size is 100-500 mesh;

[0029] The feeding rate of the second catalyst is 0.1 g / min to 100 g / min.

[0030] Further, the inert gas blown in the step S3) is nitrogen, argon or helium, and the flow rate is 0.5 L / min to 20 L / min.

[0031] Compared with the prior art, the continuous and stable preparation device and method of single-walled carbon nanotubes of the present invention have the following outstanding beneficial effects:

[0032] The present invention is initiated by a plasma arc between graphite electrodes, which not only makes full use of the high temperature of the plasma to evaporate the catalyst, but also avoids the disadvantages of arc ignition between the graphite cathode and the liquid catalyst anode in the conventional method. While reducing the catalyst evaporation rate, it overcomes the problem of arc interruption caused by metal droplet sputtering and coking in the liquid electrode. By using a convex crucible anode to avoid a series of disadvantages of the conventional scheme, the continuous stability of the reaction is greatly improved, and the stable and continuous preparation of single-walled carbon nanotubes is realized. Description of the Drawings

[0033] Figure 1 is a schematic structural diagram of the preparation device of the present invention;

[0034] Figure 2 is a scanning electron microscope image of the carbon nanotube product;

[0035] Figure 3 is a Raman spectrum diagram of the carbon nanotube product. Detailed Embodiments

[0036] The present invention will be further described in detail below with reference to the drawings and embodiments.

[0037] As Figure 1 shown, a continuous and stable preparation device for single-walled carbon nanotubes, the structure of the device includes a hollow graphite 4, a graphite crucible 1, a plasma arc furnace body 3, an air inlet 2, and a discharge port 5. Among them, the hollow graphite 4 serves as the cathode of the plasma arc furnace, and the graphite crucible 1 serves as the anode of the plasma arc furnace.

[0038] The graphite crucible 1 is a structure with a protruding middle part for containing a metal catalyst;

[0039] The graphite crucible 1 is arranged at the bottom of the device, and the hollow graphite 4 is arranged directly above the graphite crucible 1;

[0040] The diameter of the middle protruding part of the graphite crucible 1 is equivalent to the diameter of the hollow graphite 4.

[0041] The middle protruding part of the graphite crucible 1 is 2 to 20 cm higher than the liquid level of the contained metal catalyst;

[0042] The power of the power supply of the plasma arc furnace is 20 - 1000 kW, the current is 100 - 10000 A, and the voltage is 10 - 500 V.

[0043] Example 1

[0044] Adopt Figure 1 The device for continuously preparing single - wall carbon nanotubes stably shown in the figure. This device consists of a hollow graphite 4 cathode, a graphite crucible 1 anode, a furnace body 3 and an auxiliary system. The middle part of the graphite crucible 1 anode protrudes, is 8 cm higher than the metal catalyst, and the diameter is equivalent to the diameter of the cathode; among them, the power of the plasma power supply is 150 kW, the current is 1000 A, and the voltage is 150 V.

[0045] Process for preparing single - wall carbon nanotubes:

[0046] S1) Place the first catalyst, Fe 60% - Mo 40% alloy, in the graphite crucible 1;

[0047] S2) Introduce the plasma gas argon with a flow rate of 40 L / min, turn on the plasma power supply, generate a plasma arc between the anode and the cathode, and melt the first catalyst in the graphite crucible 1 until the furnace temperature rises to 1300 °C;

[0048] S3) After mixing the carbon source gas and the carrier gas, carry the second catalyst into the reaction furnace through the hollow graphite 4 cathode. The volume fraction in the mixed gas is 40% methane, 20% hydrogen, and the rest is argon, with a flow rate of 80 L / min; the second catalyst is 10% sulfur powder and 90% iron powder, with a particle size of 200 mesh and a feeding rate of 5 g / min; the product is introduced into the furnace body through the air inlet and purged with an inert gas and discharged. Continuously collect the single - wall carbon nanotube product. The inert gas is argon with a flow rate of 5 L / min.

[0049] The reaction can proceed stably continuously. After 72 hours of reaction and ending, collect the product, weigh it, and calculate that the single - wall carbon nanotube yield can reach ~ 890 g / h. Calcinate it in a muffle furnace at 900 °C for 2 hours, weigh the ash content, and calculate that the product purity is 82.4%. The morphology of the product is observed by a scanning electron microscope as shown in Figure 2 shown, and the crystallinity is evaluated by the intensity ratio of the G peak and the D peak in the Raman spectrum, as shown in Figure 3As shown, the G / D ratio is ~64.5.

[0050] Example 2

[0051] Adopt Figure 1 The device for stable and continuous preparation of single-walled carbon nanotubes shown in the figure. This device consists of a hollow graphite 4 cathode, a graphite crucible 1 anode, a furnace body and an auxiliary system. The middle part of the graphite crucible 1 anode protrudes, 2 cm higher than the metal catalyst, and the diameter is equivalent to that of the cathode. Among them, the power of the plasma power supply is 20 kW, the current is 100 A, and the voltage is 20 V.

[0052] Process for preparing single-walled carbon nanotubes:

[0053] S1) Place the first catalyst, Fe 60%-Ta 40% alloy, in the graphite crucible 1.

[0054] S2) Introduce the plasma gas argon with a flow rate of 10 L / min, turn on the plasma power supply, generate a plasma arc between the anode and the cathode, and melt the first catalyst in the graphite crucible 1 until the furnace temperature rises to 900 °C.

[0055] S3) After mixing the carbon source gas and the carrier gas, carry the second catalyst into the reaction furnace through the hollow graphite 4 cathode. The volume fraction in the mixed gas is 10% ethylene, 35% hydrogen, and the rest is argon, with a flow rate of 10 L / min. The second catalyst is 10% selenium powder and 90% cobalt powder, with a particle size of 200 mesh, and the feeding rate is 0.1 g / min. The product is introduced into the furnace body through the air inlet and purged with an inert gas, and the single-walled carbon nanotube product is continuously collected. The inert gas is argon, with a flow rate of 0.5 L / min.

[0056] The reaction can proceed stably and continuously. After 72 hours of reaction, the product is collected, weighed, and the yield of single-walled carbon nanotubes can reach ~20 g / h. The product is calcined in a muffle furnace at 900 °C for 2 hours, weighed for the ash content, and the product purity is calculated to be 76.3%.

[0057] Example 3

[0058] Adopt Figure 1 The device for stable and continuous preparation of single-walled carbon nanotubes shown in the figure as Figure 1 shown. This device consists of a hollow graphite 4 cathode, a graphite crucible 1 anode, a furnace body and an auxiliary system. The middle part of the graphite crucible 1 anode protrudes, 20 cm higher than the metal catalyst, and the diameter is equivalent to that of the cathode. Among them, the power of the plasma power supply is 1000 kW, the current is 10000 A, and the voltage is 100 V.

[0059] Process for preparing single-walled carbon nanotubes:

[0060] S1) Place the first catalyst, iron, in the graphite crucible 1.

[0061] S2) Introduce argon, a plasma gas, with a flow rate of 500 L / min. Turn on the plasma power supply to generate a plasma arc between the anode and the cathode, melting the first catalyst in the graphite crucible 1 until the furnace temperature rises to 1500 °C;

[0062] S3) After mixing the carbon source gas and the carrier gas, carry the second catalyst into the reaction furnace through the hollow graphite 4 cathode. The volume fraction in the mixed gas is 80% acetylene, 15% hydrogen, and the rest is argon, with a flow rate of 200 L / min; The second catalyst is 20% ferrous sulfide powder and 80% nickel powder, with a particle size of 200 mesh and a feeding rate of 100 grams per minute; The product is purged out of the furnace body by introducing an inert gas through the inlet, and the single-walled carbon nanotube product is continuously collected. The inert gas is argon, with a flow rate of 20 L / min.

[0063] The reaction can proceed stably and continuously. After 72 hours of reaction, the product is collected and weighed. The yield of single-walled carbon nanotubes can reach ~3570 g / h. It is calcined in a muffle furnace at 900 °C for 2 hours and weighed for the ash content. The product purity is calculated to be 75.6%.

[0064] Example 4

[0065] Adopt Figure 1 The device for stable and continuous preparation of single-walled carbon nanotubes as shown. This device consists of a hollow graphite 4 cathode, a graphite crucible 1 anode, a furnace body, and an auxiliary system. The middle part of the graphite crucible 1 anode protrudes, 8 cm higher than the metal catalyst, and the diameter is equivalent to that of the cathode; Among them, the plasma power supply has a power of 300 kW, a current of 1500 A, and a voltage of 200 V.

[0066] Process for preparing single-walled carbon nanotubes:

[0067] S1) Place the first catalyst, an Fe60%-Co40% alloy, in the graphite crucible 1;

[0068] S2) Introduce argon, a plasma gas, with a flow rate of 20 L / min. Turn on the plasma power supply to generate a plasma arc between the anode and the cathode, melting the first catalyst in the graphite crucible 1 until the furnace temperature rises to 1000 °C;

[0069] S3) After mixing the carbon source gas and the carrier gas, carry the second catalyst into the reaction furnace through the hollow graphite 4 cathode. The volume fraction in the mixed gas is 40% propylene, 20% hydrogen, and the rest is argon, with a flow rate of 100 L / min; The second catalyst is 40% Ni3S4 powder and 60% iron powder, with a particle size of 200 mesh and a feeding rate of 7.5 grams per minute; The product is purged out of the furnace body by introducing an inert gas through the inlet, and the single-walled carbon nanotube product is continuously collected. The inert gas is argon, with a flow rate of 10 L / min.

[0070] The reaction can proceed continuously and stably. After 72 hours, the product is collected and weighed. The yield of single-walled carbon nanotubes can reach ~1450 g / h. The product is calcined in a muffle furnace at 900 °C for 2 hours, and the ash is weighed to calculate the product purity of 83.4%.

[0071] Example 5

[0072] Adopt the device for continuously and stably preparing single-walled carbon nanotubes as shown in Figure 1 . The device consists of a hollow graphite 4 cathode, a graphite crucible 1 anode, a furnace body and an auxiliary system. The middle part of the graphite crucible 1 anode protrudes, 5 cm higher than the metal catalyst. The diameter is equivalent to that of the cathode. Among them, the power of the plasma power supply is 300 kW, the current is 1500 A, and the voltage is 200 V.

[0073] Process for preparing single-walled carbon nanotubes:

[0074] S1) Place the first catalyst, an alloy of 30% Fe - 30% Co - 40% Ta, in the graphite crucible 1;

[0075] S2) Introduce the plasma gas argon with a flow rate of 20 L / min. Turn on the plasma power supply to generate a plasma arc between the anode and the cathode, melting the first catalyst in the graphite crucible 1 until the furnace temperature rises to 1100 °C;

[0076] S3) After mixing the carbon source gas and the carrier gas, carry the second catalyst into the reaction furnace through the hollow graphite 4 cathode. The volume fraction in the mixed gas is 40% propane, 20% hydrogen, and the rest is argon, with a flow rate of 100 L / min; the second catalyst is 20% CoS powder and 80% iron powder, with a particle size of 200 mesh and a feeding rate of 7.5 g / min; the product is introduced into the furnace body through the gas inlet and purged with inert gas, and the single-walled carbon nanotube product is continuously collected. The inert gas is argon with a flow rate of 10 L / min.

[0077] The reaction can proceed continuously and stably. After 72 hours, the product is collected and weighed. The yield of single-walled carbon nanotubes can reach ~1785 g / h. The product is calcined in a muffle furnace at 900 °C for 2 hours, and the ash is weighed to calculate the product purity of 84.5%.

[0078] Comparative Example 1

[0079] This comparative example has the same equipment parameters and experimental parameters as Example 1, except that the graphite crucible 1 anode in the comparative example does not have a middle convex structure, and the others are the same. Due to blockage and arc interruption after the reaction, the reaction is not continuous, and only a 2-hour experiment can be carried out. The product is collected and the yield is calculated to be ~245 g / h. The product purity is obtained by thermal analysis as 43.5%.

[0080] The experimental results of the examples and comparative examples are summarized as follows:

[0081]

[0082] As can be seen from the above data summary, the growth efficiency of single-walled carbon nanotubes in the embodiments of the present invention is significantly improved, and the purity and the growth efficiency of single-walled carbon nanotubes are significantly enhanced.

[0083] The above-described embodiments are only relatively preferred specific embodiments of the present invention. Ordinary changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A continuous and stable preparation device for single-walled carbon nanotubes, characterized in that, The structure of the device includes a hollow graphite (4), a graphite crucible (1), a plasma arc furnace body (3), an air inlet (2), and a discharge port (5). Among them, the hollow graphite (4) serves as the cathode of the plasma arc furnace, and the graphite crucible (1) serves as the anode of the plasma arc furnace. The graphite crucible (1) has a structure with a protruding middle part for holding a metal catalyst. The graphite crucible (1) is arranged at the bottom of the device, and the hollow graphite (4) is arranged directly above the graphite crucible (1). The diameter of the protruding middle part of the graphite crucible (1) is equivalent to the diameter of the hollow graphite (4).

2. The continuous and stable preparation device for single-walled carbon nanotubes according to claim 1, characterized in that The protruding middle part of the graphite crucible (1) is 2 to 20 cm higher than the liquid level of the metal catalyst it holds. The power of the power supply of the plasma arc furnace is 20 to 1000 kW, the current is 100 to 10000 A, and the voltage is 10 to 500 V.

3. A method for stably and continuously preparing single-walled carbon nanotubes based on claim 1 or 2, characterized in that, The method is to strike an arc between the protruding parts of the hollow graphite (4) and the graphite crucible (1), heat and melt the first catalyst placed in the graphite crucible (1) through the plasma arc, and make the furnace temperature of the furnace body (3) reach the specified temperature; at this time, introduce a carbon source gas mixture and a second catalyst component into the furnace body (3), obtain single-walled carbon nanotube products through high-temperature chemical reactions, and then discharge them from the discharge port (5) out of the furnace body (3) to collect single-walled carbon nanotube products.

4. A method for stably and continuously preparing single-walled carbon nanotubes according to claim 1, characterized in that, The method specifically includes the following steps: S1) Place the first catalyst in the graphite crucible (1). S2) Introduce a plasma gas, turn on the plasma power supply, generate a plasma arc between the anode and the cathode, melt the first catalyst in the graphite crucible (1) until the furnace temperature rises to the specified temperature. S3) After mixing the carbon source gas and the carrier gas, carry the second catalyst into the furnace body (3) from the hollow graphite cathode (4), and purge the product through the air inlet (2) with an inert gas and discharge it from the furnace body (3) to continuously collect single-walled carbon nanotube products.

5. A method for stably and continuously preparing single-walled carbon nanotubes according to claim 4, characterized in that, In the step S1), the first catalyst is iron, cobalt, nickel metal or a mixture thereof.

6. A method for stably and continuously preparing single-walled carbon nanotubes according to claim 4, characterized in that, In the step S1), the first catalyst is an alloy or mixture of iron, cobalt, nickel and refractory metals, where the refractory metal elements are molybdenum, tungsten, tantalum, niobium, hafnium or zirconium, and the weight ratio content of the refractory metal elements is 20 to 60%.

7. A method for stably and continuously preparing single-walled carbon nanotubes according to claim 4, characterized in that, In the step S2), the arc gas is any one, two or more mixtures of argon, nitrogen, helium, hydrogen, water vapor, and the flow rate is 10 L / min to 500 L / min. The specified temperature of the furnace is 900 to 1500 °C.

8. A method for stably and continuously preparing single-walled carbon nanotubes according to claim 4, characterized in that, In the step S3), the carbon source gas is any one of methane, ethylene, acetylene, propylene, propane. The carrier gas is a mixture of nitrogen, argon or helium and hydrogen, where the volume of the carbon source gas is 10 to 80%; the volume of hydrogen is 0 to 35%, and the rest is an inert gas, and the flow rate is 10 L / min to 200 L / min.

9. A method for stably and continuously preparing single-walled carbon nanotubes according to claim 4, characterized in that, In the step S3), the second catalyst is a mixed powder of 50 to 95% metal powder and 5 to 50% promoter. Wherein the metal powder is any one or a combination of iron, cobalt, and nickel, and the particle size is 50 to 350 mesh; The promoter is any one of sulfur powder, selenium powder, iron sulfide, ferrous sulfide, nickel sulfide, cobalt sulfide, etc. and their mixtures, and the particle size is 100 to 500 mesh; The feeding rate of the second catalyst is 0.1 g / min to 100 g / min.

10. A method for stably and continuously preparing single-walled carbon nanotubes according to claim 4, characterized in that, The inert gas blown in the step S3) is nitrogen, argon or helium, and the flow rate is 0.5 L / min to 20 L / min.

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