JP2022134552A - Apparatus and method for vapor phase synthesis of high-crystal high-purity carbon nanotube - Google Patents

Abstract

To provide an apparatus and a method for synthesizing a carbon nanotube capable of obtaining a high-purity small-diameter carbon nanotube in a high yield by reducing a metal impurity content derived from catalyst metal nanoparticles.SOLUTION: According to the present invention, catalyst metal nanoparticles are grown to an allowable lower limit size in an apparatus for producing catalyst particles having a microplasma space with at least one side thereof having a size in the order of millimeters or less, and are blown at a high speed into a reaction vessel in which a carbon raw material exists to immediately react with the carbon raw material. Thereby, the growth into particles larger than the allowable upper limit size caused by the aggregation between the particles is suppressed.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to an apparatus and method for synthesizing small-diameter carbon nanotubes by a vapor phase method.

The vapor-phase method, which is one of the methods for synthesizing small-diameter carbon nanotubes such as single-walled carbon nanotubes, disperses nanoparticles made of catalytic metals in the gas phase as an aerosol and mixes them with carbon raw materials at high temperatures. , is a method for starting the growth of carbon nanotubes from the surface of catalytic metal nanoparticles, and the arc discharge method (see Patent Document 1), the laser evaporation method, and the thermal chemical vapor deposition (CVD) method (see Patent Document 2) are known. there is

Small-diameter carbon nanotubes produced by the vapor phase method have excellent crystallinity, but have the disadvantage that they contain a large amount of metal impurities derived from catalyst metal nanoparticles and carbon impurities of various forms. Therefore, in order to use the small-diameter carbon nanotubes produced by the gas-phase method industrially, it is essential to purify them by complicated processes. It has been difficult to synthesize at low cost.

JP-A-7-197325 JP-A-2001-80913 JP-A-2005-35841 JP 2017-66506 A

In the synthesis of small-diameter carbon nanotubes by the conventional gas-phase method, many metals such as iron used as catalyst metal nanoparticles exist as impurities. In particular, this tendency becomes remarkable when catalyst metal nanoparticles are generated in the gas phase at a high number density in order to increase the productivity of small-diameter carbon nanotubes.
The present invention aims to provide a carbon nanotube synthesizing apparatus and a method for synthesizing carbon nanotubes that can reduce the content of metal impurities derived from catalytic metal nanoparticles and, as a result, obtain small-diameter carbon nanotubes with high purity in a high yield. , as a task.

The present inventors have investigated the conditions for metal nanoparticles to function as catalysts for the growth of small-diameter carbon nanotubes, and have come to the knowledge that there is a permissible range of particle sizes. Based on this knowledge, after first growing the catalyst metal nanoparticles to the lower allowable size, in order to suppress the growth of particles larger than the allowable upper limit size due to agglomeration between particles, carbon raw material gas was immediately added. It was found that it is important to react. Furthermore, in order to increase the productivity of small-diameter carbon nanotubes, when catalyst metal nanoparticles are generated in the gas phase at a high number density, each of these series of process times is set to suppress coarsening due to aggregation. The need for control on the millisecond order led to the completion of the present invention.
In the present invention, in order to control each of the above series of processes in a short time on the order of milliseconds, catalyst metal nanoparticles are produced by a catalyst particle production apparatus having a micro plasma space with at least one side size of millimeter order or less. do it inside Furthermore, by blowing the gas containing catalyst metal nanoparticles at high speed into the reaction vessel where the carbon raw material exists, it immediately reacts with the carbon raw material, and the particles grow to be coarser than the allowable upper limit size due to aggregation between the particles. to prevent it from collapsing.

The present invention relates to the following carbon nanotube synthesis apparatus (1) to (5).
(1) A carbon nanotube synthesizing device comprising a catalyst particle production device for producing catalytic metal nanoparticles by decomposing a gaseous catalytic metal precursor material with plasma, wherein the catalytic particle production device comprises a catalytic metal precursor Means for supplying a gas containing a substance, a micro-plasma generator for generating micro-plasma in a micro-space through which at least part of the gas supplied by the means passes, and catalyst metal nanoparticles generated by the micro-plasma and a catalyst particle outlet for blowing an aerosol-like gas to the outside.
(2) The catalyst particle outlet of the catalyst particle production apparatus is located at a distance of 1 mm to 30 mm from the most upstream position where the gaseous catalyst metal precursor material can come into contact with the microplasma, and has at least one side length. The apparatus for synthesizing carbon nanotubes according to (1) above, wherein the length is 0.1 mm to 3 mm.
(3) A carbon raw material gas supply means for blowing out a gas containing a carbon raw material from a carbon raw material outlet, wherein at least one side of the carbon raw material outlet is 0.1 to 3 mm, and the carbon raw material gas is supplied from the carbon raw material outlet. , a carbon raw material gas supply means for blowing out toward a gas mixing position located within a range of 0 to 30 mm along the direction in which the gas containing the catalyst metal nanoparticles blows out from the catalyst particle outlet of the catalyst particle production apparatus. , the apparatus for synthesizing carbon nanotubes according to (1) or (2) above.
(4) The carbon nanotube synthesizing apparatus according to (3) above, wherein the carbon source gas supply means has a means for preheating the carbon source gas.
(5) Means for heating the gas staying downstream from the gas mixing position, comprising the catalyst metal nanoparticles blown out from the catalyst particle production apparatus and the carbon source gas blown out from the carbon source gas supply means; The carbon nanotube synthesizing apparatus according to (3) or (4) above, which has heating means for generating carbon nanotubes inside the gas by heating the gas mixed with the above.

The present invention also relates to a method for synthesizing a carbon nanotube of (6) below.
(6) In a catalyst particle production apparatus, a gas containing a high-concentration catalytic metal precursor material is passed through a minute plasma space to produce a gas containing small-sized catalytic metal nanoparticles at a high number density, and the gas is is blown out from the outlet of the catalyst particle production apparatus to the outside where the carbon source gas exists, and the catalyst metal nanoparticles and the carbon source gas are mixed and contacted, thereby growing carbon nanotubes from the surface of the catalyst metal nanoparticles. A method for synthesizing carbon nanotubes, characterized by initiating

According to the present invention, the catalyst metal nanoparticles generated in the micro plasma are mixed with the carbon raw material in a short time, so that they aggregate into coarse particles and are not used in the synthesis of carbon nanotubes and become impurities. The amount of ingredients can be reduced. In addition, since the catalyst metal nanoparticles are mixed with the carbon raw material after the catalyst metal nanoparticles have grown to the allowable lower limit size or more, the atomic or cluster-shaped extremely small metal particles come into contact with the high-concentration carbon raw material, and are converted into amorphous carbon. A catalyst deactivation reaction resulting in coating can be avoided. As a result, most of the catalytic metal component supplied to the gas phase can be utilized for carbon nanotube synthesis.
As a result, it becomes possible to efficiently synthesize highly crystalline, high-purity, small-diameter carbon nanotubes by the gas-phase method using microplasma of the present invention.

One conceptual diagram of the carbon nanotube synthesis apparatus of the present invention One conceptual diagram of the carbon nanotube synthesis apparatus of the present invention Schematic diagram of the catalyst particle production apparatus of the present invention Schematic diagram of one embodiment of the catalyst particle production apparatus of the present invention SEM photograph of small-diameter carbon nanotubes produced in Examples

An embodiment of the present invention will be described with reference to the drawings.
In this specification, "-" between numerical values means including the preceding and following numerical values, and for example, "1 to 2" means "1 or more and 2 or less".
FIG. 1 is a conceptual diagram of a carbon nanotube synthesizing apparatus of the present invention. Hereinafter, "carbon nanotube" may be described as "CNT".

The CNT synthesis apparatus of the present invention, as shown in one conceptual diagram in FIG. Supply means 105 and carrier gas supply means 106 are provided.
The principle of CNT synthesis is that aerosol-like catalyst metal nanoparticles blown into the reaction vessel 101 from the catalyst particle outlet of the catalyst particle production device 102 are mixed at the gas mixing position 107 in the CNT growth space 104 near the outlet. By mixing with the carbon raw material supplied from the carbon raw material gas supply means 105, the growth of CNTs is started from the surface of the catalytic metal nanoparticles, and further, the gas mixing position is set by the gas flow of the carrier gas supplied from the carrier gas supply means 106. The gas is retained in the CNT growth space 104 on the downstream side from 107 and heated by the heating means 103 to promote the growth of CNTs, and the CNTs generated inside the gas are collected by the collecting means 108 such as a filter. is.
In addition, a plurality of catalyst particle production apparatuses and carbon source gas supply means may be provided, and a plurality of carrier gas supply means may be provided.

Another conceptual diagram of the CNT synthesis apparatus of the present invention is shown in FIG.
A gas containing catalytic metal nanoparticles is blown out from the catalyst particle production device 202 into the reaction vessel 201 from the catalyst particle outlet 210 of the catalyst particle production device 202 . This gas is supplied from the carbon raw material gas supply means 205 at the gas mixing position 207 in the CNT growth space 204, and is quickly mixed with the carbon raw material gas containing the carbon raw material blown out from the carbon raw material outlet 211. It is possible to suppress the catalyst particles from coarsely growing to the allowable upper limit size or more, and immediately react with the carbon raw material to start the growth of CNTs from the surface of the catalyst metal nanoparticles.

Since the carbon raw material gas supply means 205 blows out the carbon raw material gas containing the carbon raw materials from the carbon raw material outlet 211 toward the gas mixing position 207 at high speed, the carbon raw material outlet 211 has at least one side that is thin, for example, a narrow tube or the like. It preferably has a shape such as a slit, and preferably has at least one side of 3 mm or less. Further, the carbon raw material outlet 211 is preferably close to the gas mixing position 207, and preferably located at a distance of 30 mm or less from the gas mixing position 207.
As a result, the gas containing catalyst metal nanoparticles blown out from the catalyst particle production apparatus 202 collides with the carbon raw material gas at the gas mixing position 207, and these two types of gases can be quickly mixed.

Although the angle formed by the directions of these two kinds of gases is not particularly limited, it is easier for them to mix when they collide with each other at a certain angle. That is, two kinds of gases are collided head-on at an angle of 180 degrees, or at an angle of 90 degrees, for example, a gas containing catalyst metal nanoparticles is blown out from the tip of a fine tube, and the carbon raw material gas is caused to flow laterally through an annular slit. Arrangements for feeding from
In addition, in order to increase the growth efficiency of CNT, it is desirable that the carbon raw material be rapidly decomposed on the surface of the catalyst particles and converted into CNTs. A heating means 203 for heating the CNT growth space 204 may be used as a preheating means for the means 205 .

In addition, it is desirable to provide a carrier gas supply means 206 for the purpose of preventing the mixed gas containing the catalyst metal nanoparticles and the carbon raw material from flowing back in the reaction vessel 201 and staying in the heated CNT growth space 204. . As the gas supplied from the carrier gas supply means 206, in order to continue the growth of CNTs, an additional carbon material, a reducing gas such as hydrogen, or a reaction accelerator for CNT growth may be supplied.

After that, it is the same as a known gas phase CNT synthesis apparatus, and if a mixed gas containing catalyst metal nanoparticles and carbon raw materials is allowed to stay in the heated CNT growth space 204 in the reaction vessel 201, CNTs grow. can be continued. This CNT growth space 204 is a continuous space heated to 600 to 1400° C. by a heating means 203 such as a resistance heating furnace, infrared heating furnace, or induction heating furnace. A means for evacuation, such as a pump, may be provided downstream of the CNT growth space 204 . Means for recovering the CNTs produced in the CNT growth space 204, such as a filter 209, is provided downstream of the CNT growth space 204 to recover the produced CNTs.

The catalyst particle production apparatus of the present invention comprises a container 315, a minute plasma generating electrode 313, a catalyst metal precursor material gas supply means 312, and a catalyst particle outlet 310, as shown in the conceptual diagram of FIG.
The catalyst particle production apparatus generates micro plasma 314 in the micro space inside the container 315 by the micro plasma generation electrode 313 inside the container 315 , and gas is supplied to the micro plasma 314 by the catalytic metal precursor material gas supply means 312 . By supplying at least a part of the gas containing the catalyst metal precursor material in the form of a plasma, the catalyst metal catalyst precursor material is decomposed by the reaction with the plasma to generate cluster-like catalyst metal atoms, and the clusters are further separated into Agglomeration and particle size growth generate an aerosol-like gas containing catalyst metal nanoparticles larger than the allowable lower limit size near the catalyst particle outlet 310, which is blown out of the apparatus from the catalyst particle outlet 310. Let Inside the container 315, there may be gas supply means 316 other than the catalyst metal precursor material gas supply means.

Here, the minute plasma is a plasma generated in a minute space having at least one side size of 10 mm or less. By using a small plasma instead of a normal-sized plasma, the catalyst metal precursor material decomposed by the plasma can be transported to the catalyst particle outlet in a short time after decomposition, and the growth of the catalyst metal nanoparticles can be accelerated. It is possible to keep the size below the allowable upper limit size.
The travel distance of the gas from the position where the gaseous catalyst metal precursor material can contact the micro plasma 314 to the position of the catalyst particle outlet 310 is , too short is also undesirable. Specifically, it is preferably 1 mm or more.
At the same time, the distance must be short so that the catalyst metal nanoparticles do not grow coarsely to the allowable upper limit size or more when they reach the outlet, and is preferably 30 mm or less, more preferably 20 mm or less, and further. It is preferably 15 mm or less. Similarly, the flow velocity of the gas supplied from the catalyst metal precursor substance gas supply means 312 into the micro plasma 314 is preferably high, preferably 1 m/sec or more.

At least one side of the catalyst particle outlet 312 is thin, and preferably has a narrow tube or slit shape, and at least one side is 3 mm or less, more preferably 2 mm or less, and still more preferably 1.5 mm or less. By narrowing the area of the outlet, the gas containing the catalyst metal nanoparticles that is blown out from the outlet is blown out at high speed, and by making the gas flow thinner on one side, the carbon raw material gas on the outside can be quickly mixed with the gas. This is for mixing. However, if the outlet is too narrow, the catalyst particles tend to stick to the wall surface, so the size of one side of the outlet is preferably 0.1 mm or more. The flow velocity for blowing gas from the catalyst particle outlet is desirably 1 m/sec or more. As a result, it is possible to quickly mix the carbon-containing gas supplied to the outside of the blower outlet near the blower outlet, thereby suppressing the coarse growth of the catalyst metal nanoparticles beyond the allowable upper limit size due to the agglomeration of the catalyst metal nanoparticles. CNTs can be grown by immediately reacting with the carbon source gas.

The micro plasma generation device or generation method in the catalyst particle production apparatus is not particularly limited. is generated by supplying and discharging For example, there is a method of generating inside a fine tube as described in Patent Document 3, and a method of generating between narrow slits as described in Patent Document 4.
In addition, there is also a method of ejecting a medium such as argon gas, which is easy to discharge, in the form of a fine jet, and discharging the jet to generate minute plasma. The power to be supplied may be DC power, pulse power, AC power, or high-frequency power ranging from the kilohertz band to the gigahertz band.

A schematic diagram of one embodiment of the catalyst particle production apparatus of the present invention is shown in FIG.
A fine tube 417 made of an insulating material is used as a container, and a coil-shaped electrode 419 is placed outside the tip of the fine tube 417 and a metal wire 418 is placed inside the fine tube 417 as a micro plasma generating electrode. A gas containing a catalytic metal precursor material is supplied from the root side of the fine tube 417, and high-frequency power is supplied from the high-frequency generator 420 to the coil-shaped electrode 419, so that the inside of the fine tube 417 around which the coil-shaped electrode 419 is wound. to generate minute plasma 414 . The catalyst metal catalyst precursor material is decomposed by the reaction with the micro plasma 414 to generate cluster-like catalyst metal atoms, and the clusters are aggregated together to generate an aerosol-like gas containing catalyst metal nanoparticles. , catalyst particle outlet 410 , i.e., the tip of fine tube 417 , to the outside.

In order to quickly mix the gas containing catalytic metal nanoparticles blown out from the catalyst particle outlet 410 with the carbon raw material gas, the gas mixing position needs to be near the catalyst particle outlet 410. It is preferably positioned within 30 mm along the direction in which the gas containing the catalyst metal nanoparticles blows out. Since this gas mixing position is in the heated CNT growth space, the vicinity of the outlet of the catalyst particle production apparatus must be made of a material with high heat resistance and carburization resistance.

Kinds of catalyst metal, catalyst metal precursor material, and carbon raw material used in the present invention, and methods of supplying them are not particularly limited as long as they are used in CNT synthesis by the vapor phase method.
As the catalyst metal, transition metal atoms are preferably used, and iron, cobalt, nickel, scandium, titanium, vanadium, chromium, manganese, etc., can be mentioned. Of these, iron, cobalt and nickel are more preferable. An alloy composed of a plurality of elements may also be used.
The catalytic metal precursor substance is a compound containing metal atoms constituting the catalytic metal, and is preferably a substance having a high vapor pressure that can be easily supplied in gaseous form. For example, when the catalytic metal is iron, ferrocene and its Derivatives such as iron pentacarbonyl, iron chloride, iron acetylacetonate, and the like.

Furthermore, a compound containing sulfur atoms or oxygen atoms as a reaction accelerator may be supplied from the carrier gas supply means to the CNT growth space, supplied to the catalyst particle production apparatus together with the catalyst metal precursor material, or supplied to the catalyst particle production apparatus. may be mixed with and supplied from the carbon raw material gas supply means.
This reaction accelerator can interact with the catalyst metal to promote the production of small-diameter carbon nanotubes. As the sulfur compound, organic sulfur compounds and inorganic sulfur compounds can be used. Examples of organic sulfur compounds include sulfur-containing heterocyclic compounds such as thianaphthene, benzothiophene, and thiophene, and inorganic sulfur compounds include, for example, Elemental sulfur, hydrogen sulfide, and the like can be mentioned. Compounds containing oxygen atoms include oxygen molecules, carbon monoxide, carbon dioxide, and water.

Various gaseous organic compounds can be selected as the carbon material, and hydrocarbons are typically used, such as methane, ethylene, propylene, and acetylene.

Further, in order to carry out the reaction rapidly and uniformly, the catalyst metal precursor substance and the carbon source gas are preferably supplied to the production apparatus together with a reducing gas or an inert gas. Hydrogen, and inert gases such as nitrogen, argon and helium are preferably used.
The produced small-diameter CNTs have diameters in the range of about 1 to 5 nm, and the number of layers is mainly composed of single-walled or double-walled and triple-walled CNTs. Further, the small-diameter CNTs produced are characterized by having high crystallinity with few defects, and characterized by an intensity ratio of 30 or more between the G band and the D band in Raman scattering analysis. Here, the G band in Raman scattering analysis is a vibrational mode observed near 1590 cm −1 , and the D band is a vibrational mode observed near 1350 cm −1 , which is considered as a peak derived from defects in carbon nanotubes. is. Further, the produced small-diameter CNTs are characterized by having a low metal impurity content of 10 atomic % or less.
According to the present invention, highly crystalline, small-diameter CNTs having an average diameter in the range of 1 to 5 nm can be synthesized with high purity.

Specific examples of the present invention will be described below.

A fine tube made of alumina having an outer diameter of 2.5 mm and an inner diameter of 1.5 mm was used as the container of the catalyst particle production apparatus. Wrapped around. The structure was such that it was inserted from one end of a quartz tube used as a reaction vessel of a CNT synthesis apparatus. Further, carrier gas supply means, which is a pipe for supplying nitrogen gas to the outside of the catalyst particle production apparatus, was provided.
A container containing ferrocene (Fe(C ₅ H ₅ ) ₂ ) powder as a catalytic metal precursor material was heated to 50°C, and argon gas (10 sccm) was supplied to heat the ferrocene-containing gas to 50°C. It was transported in piping heated to above. Also, as a reaction accelerator, a container containing elemental sulfur was heated to 120° C., and argon gas (40 sccm) was supplied, whereby the sulfur-containing gas was transported through a pipe heated to 120° C. or higher. These two gases were mixed with 150 sccm of argon gas and 10 sccm of hydrogen while being heated, and this mixed gas was supplied from the root side of the fine tube of the catalyst particle production apparatus as a catalytic metal precursor gas.
A high-frequency power (450 MHz, 30 W) was supplied to the coiled electrode to generate minute plasma in a range of about 10 mm from the tip inside the fine tube around which the coiled electrode was wound. The flow velocity of the gas supplied into the minute plasma was about 2 m/sec.

The carbon source gas supply means is preheated (925° C.) in a resistance heating furnace, and has a structure in which gas is jetted toward the center from an annular slit (9 mm in diameter) having a gap of 2 mm. The central part of the annular slit, that is, the carbon It was arranged so that the outflow direction of the raw material gas overlapped.
A carbon source gas mixture of acetylene (2 sccm) and hydrogen (15 sccm) with nitrogen (483 sccm) was supplied through an annular slit to the gas mixing position. The flow velocity was 1 m/sec in terms of 925°C.

The gas flow velocity of the gas containing catalytic metal nanoparticles blown out from the tip of the fine tube was 2 m/sec in terms of room temperature, and the preheated carbon raw material gas was sprayed from the side at a point 5 mm downstream from the tip of the fine tube. The mixed gas stayed downstream in the CNT growth space inside the quartz tube heated by the resistance heating furnace by the carrier gas, and moved toward the filter arranged outside the CNT growth space. After feeding the catalytic metal precursor material and the carbon feedstock for 5 minutes, the CNTs collected as a film on the filter surface, resulting in a black thin film about 20 microns thick. A product containing CNT recovered by the filter was evaluated.

Evaluation was performed by Raman spectroscopy, scanning electron microscope (SEM), transmission electron microscope (TEM), and the like. A SEM image of them is shown in FIG.
From the SEM image, a highly linear CNT network structure was clearly observed. As an index for evaluating the crystallinity of CNT and the low carbon impurity content, the ratio of the G band intensity to the D band intensity in the Raman spectroscopy spectrum was evaluated to be a high value of 39. As a result of elemental analysis by EDX, the amount of iron impurities was as small as 8 atomic %. Also, from the TEM image, it was confirmed that the average diameter of the CNTs was as small as about 1.3 nm.

According to the present invention, the catalyst particle production apparatus decomposes the catalytic metal precursor material ferrocene to synthesize catalytic metal nanoparticles of appropriate size, while immediately mixing the appropriately preheated carbon feedstock gas with the catalyst particles. This initiates CNT growth and thus allows independent control of catalyst formation and CNT synthesis.
The produced CNTs show high crystallinity and an average diameter of about 1.3 nm, suggesting that the gas-phase process using micro-plasma can synthesize single-walled CNTs with high crystallinity and small diameter with high purity. It has been shown.

101, 201 reaction vessel
102, 202 Catalyst particle production device 103, 203 Heating means 104, 204 CNT growth space 105, 205 Carbon source gas supply means 106, 206 Carrier gas supply means 107, 207 Gas mixing position 108 Recovery means 209 Filters 210, 310, 410 Catalyst Particle outlet 211 Carbon raw material outlet

312, 412 Catalytic metal precursor material gas supply means 313 Electrodes for micro plasma generation 314, 414 Micro plasma 315 Container 316 Gas supply means 417 Micro tube 418 Metal wire 419 Coiled electrode 420 High frequency generator

Claims (6)

A carbon nanotube synthesizing device comprising a catalyst particle production device for producing catalytic metal nanoparticles by decomposing a gaseous catalytic metal precursor material with plasma,
The catalyst particle production device
means for supplying a gas comprising a catalytic metal precursor material;
a minute plasma generator for generating minute plasma in a minute space through which at least part of the gas supplied by said means passes;
a catalyst particle outlet for blowing out an aerosol-like gas containing catalyst metal nanoparticles generated by micro plasma;
and a carbon nanotube synthesis apparatus. The catalyst particle outlet of the catalyst particle production apparatus is located at a distance of 1 mm to 30 mm from the most upstream position where the gaseous catalyst metal precursor material can contact the micro plasma, and has at least one side length of 0. The carbon nanotube synthesis apparatus according to claim 1, wherein the length is 0.1 mm to 3 mm. A carbon raw material gas supply means for blowing out a gas containing a carbon raw material from a carbon raw material outlet,
At least one side of the carbon raw material outlet is 0.1 to 3 mm,
The carbon raw material gas is directed from the carbon raw material outlet to a gas mixing position located within a range of 0 to 30 mm along the direction in which the gas containing the catalyst metal nanoparticles is blown from the catalyst particle outlet of the catalyst particle production apparatus. 3. The apparatus for synthesizing carbon nanotubes according to claim 1, further comprising means for supplying a carbon source gas for blowing out. 4. The apparatus for synthesizing carbon nanotubes according to claim 3, wherein said carbon source gas supply means has means for preheating the carbon source gas. Means for heating the gas staying downstream from the gas mixing position,
Heating means for generating carbon nanotubes inside the gas by heating the gas in which the catalyst metal nanoparticles blown out from the catalyst particle production apparatus and the carbon raw material gas blown out from the carbon raw material gas supply means are mixed. The carbon nanotube synthesis device according to claim 3 or 4, having In the catalyst particle production apparatus, a gas containing a high-concentration catalytic metal precursor material is passed through a minute plasma space to produce a gas containing small-sized catalytic metal nanoparticles at a high number density, and the gas is used to produce catalyst particles. The catalyst metal nanoparticles and the carbon source gas are blown out from the outlet of the manufacturing apparatus to the outside where the carbon source gas exists, and the catalyst metal nanoparticles and the carbon source gas are mixed and brought into contact with each other, thereby starting the growth of carbon nanotubes from the surface of the catalyst metal nanoparticles. A method for synthesizing a carbon nanotube, characterized by:

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