JP7255281B2 - Method for producing catalyst carrier and method for producing fibrous carbon nanostructure - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a catalyst carrier and a method for producing a fibrous carbon nanostructure.

Fibrous carbon nanostructures such as carbon nanotubes (hereinafter sometimes referred to as “CNT”; see, for example, Non-Patent Document 1) have mechanical strength, sliding properties, flexibility, semiconducting and metallic conductivity. , thermal conductivity, etc., and high chemical stability.
Therefore, in recent years, methods for efficiently producing fibrous carbon nanostructures having such excellent properties at low cost have been investigated.

Here, an arc discharge method, a laser evaporation method, a chemical vapor deposition method (CVD: Chemical Vapor Deposition method), etc. have been reported as methods for producing carbon nanotubes. Among them, the CVD method is a production method that has been extensively studied as a method suitable for large-scale synthesis, continuous synthesis, and high-purity synthesis of single-walled carbon nanotubes with excellent properties (see, for example, Non-Patent Document 2). ).

For example, in Patent Document 1, a raw material gas composed of acetylene, carbon dioxide, and an inert gas is flowed at a predetermined partial pressure to the surface of a support substrate on which a catalyst composed of Fe and Al is supported. Techniques for synthesizing carbon nanotubes on substrates have been disclosed.

Furthermore, as a more efficient method for producing carbon nanotubes, a fluidized bed method using a particulate carrier having a catalyst layer formed on its surface has been studied.

WO2012/057229

S. Iijima, Nature 354, 56 (1991). Riichiro Saito and Hisanori Shinohara, "Fundamentals and Applications of Carbon Nanotubes", Baifukan, 2004

Here, as a method for producing a catalyst carrier formed by forming a catalyst layer on the surface of a particulate carrier, there are a dry method in which a raw material gas for the catalyst is sprayed onto the surface of the particulate carrier, and a catalyst solution is poured onto the surface of the particulate carrier. There is a wet method of coating, but the wet method is said to be superior to the dry method in that the catalyst layer can be formed more uniformly.
However, in the conventional method for producing a catalyst carrier, as the size of the particulate carrier becomes smaller, it becomes difficult to form a uniform catalyst layer, and there is a problem that carbon nanotubes cannot always be produced efficiently. .
Among wet methods, there is an immersion method in which a particulate carrier is immersed in a catalyst solution. Therefore, it was sometimes impossible to form a uniform catalyst layer on the surface of the particulate carrier.
Therefore, there is a demand for a method for producing a catalyst carrier capable of forming a uniform catalyst layer on the surface of a particulate carrier.

The inventor of the present invention has made intensive studies in order to achieve the above object. Then, the present inventor found that if a catalyst solution is sprayed onto a particulate carrier that floats and flows in the vertical direction while centrifugally swirling and flowing, that is, a catalyst layer is uniformly formed on the surface of the particulate carrier. The inventors have found that it can be formed, and have completed the present invention.
The term "centrifugal floating flow" is also referred to as "rolling flow", "centrifugal rolling", etc., and refers to a state of flow in which "centrifugal swirl flow" and "floating flow" are combined. "Centrifugal swirl flow" refers to flow in a circular direction (for example, a centrifugal swirl flow direction X in FIGS. 1A and 1B to be described later).

That is, an object of the present invention is to advantageously solve the above problems, and a method for producing a catalyst carrier according to the present invention produces a catalyst carrier used in producing a fibrous carbon nanostructure. A method for producing a catalyst carrier comprising: a centrifugal floating flow step in which the particulate carrier is caused to float and flow in a vertical direction while being caused to undergo centrifugal swirling flow; and a catalyst layer forming step of forming a catalyst layer on the surface of the particulate carrier using the particulate carrier sprayed with the catalyst solution. By spraying the catalyst solution onto the centrifugally floating and flowing particulate carrier to form a catalyst layer, a catalyst carrier having a uniform catalyst layer formed on the surface of the particulate carrier can be obtained.

Here, in the method for producing a catalyst carrier of the present invention, it is preferable that the floating flow is to supply a gas to the particulate carrier to cause the floating flow in the vertical direction. By supplying a gas to the particulate carriers, the particulate carriers can be efficiently caused to float and flow in the vertical direction.

The method for producing a supported catalyst of the present invention preferably further includes a stirring step of applying a stirring force in the same direction or opposite direction to the centrifugal swirl flow direction to the centrifugally floating and flowing particulate carrier. By applying a stirring force in the same or opposite direction to the centrifugal swirling flow direction to the centrifugally floating and flowing particulate carriers, the efficiency of stirring the particulate carriers can be improved.

Further, in the method for producing a supported catalyst of the present invention, it is preferable that the particulate carrier has a porosity of 10% or less and is made of a metal oxide. If the porosity of the particulate carrier is 10% or less, the catalyst layer can be formed more uniformly. Moreover, if the particulate carrier is composed of a metal oxide, the heat resistance can be improved.

Here, in the method for producing a supported catalyst of the present invention, the metal oxide may be zirconium dioxide (zirconia), aluminum oxide or zircon. If zirconium dioxide (zirconia), aluminum oxide or zircon is used as the metal oxide, the heat resistance can be further improved. In particular, an oxide containing zirconium dioxide (zirconia) has high surface smoothness, so that the catalyst layer can be formed more uniformly.

Further, in the method for producing a supported catalyst of the present invention, in the catalyst layer forming step, the particulate carrier sprayed with the catalyst solution is heated to a temperature of 300 ° C. or higher using a fluidized bed or a rotary kiln. A catalyst layer may be formed on the surface of the carrier. A support having a calcined catalyst layer can be obtained by heating the particulate support sprayed with the catalyst solution to a temperature of 300° C. or higher using a fluidized bed or rotary kiln.

Here, in the method for producing a supported catalyst of the present invention, the catalyst solution may contain at least one metal selected from Fe, Mo, Co, and Al. If the catalyst solution contains at least one metal selected from Fe, Mo, Co, and Al, a catalyst support suitable for producing fibrous carbon nanostructures can be produced.

Further, in the method for producing a catalyst carrier of the present invention, the primary catalyst particles having the catalyst layer formed on the surface obtained in the catalyst layer forming step are caused to undergo centrifugal swirling flow and floating flow in the vertical direction. another spraying step of spraying a catalyst solution onto the primary catalyst particles centrifugally floating and flowing in the other centrifugal floating and flowing step; and using the primary catalyst particles sprayed with the catalyst solution, the primary catalyst particles. and another catalyst layer forming step of further forming a catalyst layer on the surface. By spraying the catalyst solution onto the centrifugally floating and flowing primary catalyst particles to form catalyst layers in this manner, a catalyst carrier having a plurality of uniformly formed catalyst layers on the surface of the particulate carrier can be obtained. .

Another object of the present invention is to advantageously solve the above-mentioned problems. The method is characterized by including a step of supplying a raw material gas to a carrier to synthesize a fibrous carbon nanostructure on the catalyst layer. In this way, a raw material gas is supplied to a catalyst carrier obtained by the method for producing a catalyst carrier of the present invention, and a fibrous carbon nanostructure is synthesized on the catalyst layer to produce carbon nanotubes, etc. of fibrous carbon nanostructures can be synthesized with high efficiency and is excellent in mass productivity.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the catalyst carrier which can form a catalyst layer uniformly on the surface of a particulate carrier can be provided.
Moreover, according to the present invention, it is possible to synthesize fibrous carbon nanostructures such as carbon nanotubes with high efficiency, and to provide a method for producing fibrous carbon nanostructures that is excellent in mass productivity.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing a schematic configuration of an example of a centrifugal floating fluidized device for carrying out a method for producing a catalyst carrier according to the present invention; BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing a schematic configuration of an example of a tumbling fluidization device (centrifugal floating fluidization device) for carrying out a method for producing a catalyst carrier according to the present invention; BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram for explaining a method for manufacturing a catalyst carrier according to the present invention (No. 1); It is a figure for demonstrating the manufacturing method of the catalyst carrier according to this invention (part 2). FIG. 3 is a diagram for explaining a method for manufacturing a catalyst carrier according to the present invention (No. 3); FIG. 4 is a diagram for explaining a method for manufacturing a catalyst carrier according to the present invention (No. 4);

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail.
Here, the method for manufacturing a catalyst carrier of the present invention can be used when manufacturing a catalyst carrier used when manufacturing a fibrous carbon nanostructure. In addition, the method for producing a fibrous carbon nanostructure of the present invention is suitably used when producing a fibrous carbon nanostructure using the catalyst carrier obtained by the method for producing a catalyst carrier of the present invention. can be used.

(Method for producing catalyst carrier)
The method for producing a catalyst carrier of the present invention is a method for producing a catalyst carrier used when producing a fibrous carbon nanostructure. The method for producing a catalyst carrier of the present invention comprises a step of causing the particulate carrier to float and flow in the vertical direction while causing it to undergo centrifugal swirling flow (centrifugal floatation and flow step); and a step of forming a catalyst layer on the surface of the particulate carrier using the particulate carrier sprayed with the catalyst solution (catalyst layer forming step). In addition, the method for producing a catalyst carrier of the present invention optionally includes a step of applying a stirring force (swirling force) in the same direction or opposite direction to the direction of centrifugal swirling flow to the particulate carrier that is centrifugally floating and flowing (stirring step), a step of causing the primary catalyst particles having a catalyst layer formed on the surface obtained in the catalyst layer forming step to float and flow in the vertical direction while causing centrifugal swirling flow (another centrifugal floating flow step), and another centrifugal A catalyst layer is formed on the surface of the primary catalyst particles by using a step of spraying the catalyst solution onto the primary catalyst particles centrifugally floating and flowing in the floating flow step (another spraying step) and the primary catalyst particles sprayed with the catalyst solution. and a further forming step (another catalyst layer forming step).

<Catalyst carrier>
A catalyst carrier produced by the method for producing a catalyst carrier of the present invention has a particulate carrier and one or more catalyst layers supported on the surface of the particulate carrier.
Here, the catalyst support mediates, promotes, and improves the efficiency of the synthesis and growth of fibrous carbon nanostructures in the reaction field. The catalyst carrier is not particularly limited, and plays a role of taking in the carbon raw material from the supplied raw material gas on the surface and synthesizing fibrous carbon nanostructures such as carbon nanotubes. More specifically, for example, when the catalyst has a fine particulate shape, each catalyst particle continues to produce carbon while forming a tube-like structure having a diameter corresponding to the size of the catalyst particle. Thereby, fibrous carbon nanostructures are synthesized and grown.

[Particulate carrier]
The particulate carrier has a particle shape made of an arbitrary material, and is a portion forming a base structure for supporting a catalyst by adhering, fixing, forming a film, or forming it on the surface of the carrier. In this way, when a particulate carrier is used, the catalyst carrier produced using the particulate carrier also becomes particulate.
It should be noted that the term "particulate" means that it is sufficient to form a substantially particle shape, and the aspect ratio is preferably 10 or less. When the aspect ratio of the particulate carrier is 10 or less, the catalyst solution described later can be uniformly sprayed.
In the present invention, the "aspect ratio of the particulate carrier" can be obtained by measuring the minor axis and major axis of 100 randomly selected particulate carriers using a transmission electron microscope.
The structure of the particulate carrier may be the particulate carrier alone, or a particulate carrier with an underlayer provided with an arbitrary underlayer for favorably supporting the catalyst on the surface of the particulate carrier. The underlayer is made of any material, and can be formed, for example, as one layer or two or more layers on the surface of the particulate carrier. From the viewpoint of effectively utilizing the catalyst carrier by supporting the catalyst on the particulate carrier, the particulate carrier is preferably a particulate carrier with an underlayer.
The composition of the underlayer is not particularly limited, and can be appropriately selected according to the type of particulate carrier and the type of catalyst described below. In addition, the film thickness of the underlying layer to be formed can also be appropriately adjusted according to the desired amount of supported catalyst.

The porosity of the particulate carrier is preferably 10% or less. When the porosity of the particulate carrier is 10% or less, a more uniform catalyst layer can be formed.

The material of the particulate carrier is not particularly limited, but preferably contains metal oxides, such as magnesium (Mg), aluminum (Al), silicon (Si), zirconium (Zr), and molybdenum ( Mo) more preferably contains a metal oxide containing at least one element selected from the group consisting of zirconium dioxide (zirconia), aluminum oxide, zircon and other metal oxides. preferable. Heat resistance can be improved because the particulate support is composed of a metal oxide. Also, by using zirconium dioxide (zirconia), aluminum oxide, or zircon as the metal oxide, the heat resistance can be further improved.

Although the diameter of the particulate carrier is not particularly limited, it is preferably 50 μm or more and 10 mm or less. When the diameter of the particulate carrier is 50 μm or more, separation between the particulate carrier and the CNT can be easily performed after CNT synthesis, and when the diameter is 10 mm or less, in CNT synthesis using a fluidized bed, A particulate carrier can be suspended.

〔catalyst〕
The catalyst is carried on the surface of the particulate carrier described above. In addition, the catalyst may be directly supported on the surface of the particulate carrier as a catalyst layer to constitute a catalyst carrier, or may be indirectly supported on the surface of the particulate carrier via the underlayer or the like. The catalyst carrier may be composed of (for example, particulate carrier/underlayer/catalyst layer from the inside). Further, for example, a plurality of underlying layers and/or catalyst layers may optionally be provided.
The catalyst is usually present on the surface of the catalyst support and functions to promote the synthesis of fibrous carbon nanostructures.
Further, the catalyst may contain fine metal particles having a predetermined particle size.

<Centrifugal floating flow process>
In the centrifugal floating flow step of the method for producing a catalyst carrier of the present invention, the particulate carrier is spirally rolled or rotated (or ) to allow efficient stirring.

[Centrifugal swirling flow]
The centrifugal swirl flow of the particulate carrier can be achieved by rotating the rotor with the particulate carrier placed on the rotor horizontally installed inside the cylindrical stator. In a centrifugal floating-flow device such as FIG. 1A described later, the particulate carrier rolls on the rotor while being pressed against the inner peripheral surface of the stator by centrifugal force, and in a rolling-flow device such as FIG. It rotates (revolves) around the rotation axis of the rotor when it floats and flows in the hollow space inside the stator due to force.
The number of rotations of the rotor is preferably about 50 rpm or more and 1,000 rpm or less, although there are differences in setting depending on the diameter of the apparatus.
Moreover, the temperature during the centrifugal swirling flow is not particularly limited, and can be appropriately selected according to the type of the particulate carrier, the composition of the catalyst solution described later, and the like.

[Floating flow]
When the particulate carriers are caused to undergo centrifugal swirl flow to form the catalyst layer, the particulate carriers are caused to float and flow in the vertical direction by, for example, blowing in a gas while causing the particulate carriers to undergo centrifugal swirl flow. In this way, in addition to the centrifugal swirl flow, when the centrifugal floating flow is performed in combination with the floating flow, the stirring efficiency and the drying efficiency are increased, so that the working efficiency is improved, and the catalyst solution can be uniformly applied. and other advantages.
For example, (i) floating flow air is blown from a slit provided between a rotor and a stator with a constant width toward the particles that are centrifugally swirling, or (ii) the particulate carrier cannot pass through but the gas cannot pass through. The rotor is provided with a screen that can pass through, and floating air is blown from below the rotor toward the particles that are centrifugally swirling, or (iii) the particles that are centrifugally swirling are supplied by a tubular gas supply means provided in the vicinity of the rotor. and (iv) providing a baffle plate near the rotor inside the stator that imparts a vertical circulation flow or a radial flow to the particles that are centrifugally swirling. , can produce vertical floating flow. Here, the air volume of the floating flowing air can be appropriately selected according to the purpose such as the type and capacity of the device.
It should be noted that it is possible to combine the floating flow air and the baffle plate, whereby the floating flow in the vertical direction can be generated more efficiently.

It is preferable that the temperature of the gas such as the floating flowing air is from room temperature to 100°C. When the temperature of the gas is room temperature or higher, the solvent remains without drying, preventing the particulate carrier from adhering to the centrifugal floating flow device, enabling uniform coating, and the temperature of the gas is 100°C. If it is below, static electricity will prevent the particulate carrier from adhering to the centrifugal floating fluid device, enabling uniform coating.
The gas supply rate (flow velocity) is not particularly limited, and is preferably 10.0 m/sec or more and 150 m/sec or less when using the centrifugal floating flow device of FIG. When a device is used, the speed is preferably 100.0 m/sec or more and 1500 m/sec or less.
In the case of using the centrifugal floating/flowing apparatus shown in FIG. 1A, which will be described later, if the gas supply rate is 10.0 m/sec or more, the particulate carrier can be maintained in a floating state and a sufficient stirring effect can be obtained. If it is 150 m/sec or less, scattering of the carrier particles can be prevented.
In the case of using the tumbling fluidization apparatus shown in FIG. 1B, which will be described later, if the gas supply rate is 100.0 m/sec or more, the particulate carrier can be kept in a suspended state and a sufficient stirring effect can be obtained. If it is 1500 m/sec or less, it is possible to prevent the carrier from adhering to the upper part of the device.
Sufficient stirring effect can be obtained by installing a baffle plate instead of or in addition to supplying a gas such as floating flow air to the particulate carrier to cause the particulate carrier to float and flow in the vertical direction. Obtainable. When installing a baffle plate, it is preferable to install it on the opposite side of the spraying means, not in the vicinity of the spraying means, which will be described later.

<Spraying process>
In the spraying step of the method for producing a catalyst carrier of the present invention, a coating film of the catalyst solution is uniformly formed on the surface of the particulate carrier by spraying the catalyst solution onto the particulate carrier that is centrifugally floating and flowing. can be done.
The method of spraying the catalyst solution onto the particulate carrier is not particularly limited, and suitable examples include a method of spraying from a spraying means such as a spray gun or a spray nozzle.
The conditions for spraying the catalyst solution onto the particulate carrier are not particularly limited, and known conditions can be adopted. can do. When a spray gun or the like is used for the spraying, the spray air pressure is preferably about 0.1 MPa or more and 0.5 MPa or less, for example.
In the case of spraying two or more types of catalyst solutions, a mixture of two or more types of catalyst solutions may be sprayed from one spraying means, or may be sprayed from separate spraying means. Spraying using separate spraying means is preferred.

[Catalyst solution]
The catalyst component contained in the catalyst solution preferably contains at least one metal selected from iron (Fe), molybdenum (Mo), cobalt (Co), and aluminum (Al). By containing at least one metal selected from iron (Fe), molybdenum (Mo), cobalt (Co), and aluminum (Al), the catalyst solution can function as a cocatalyst or catalyst for CNT synthesis.
As the solvent contained in the catalyst solution, alcohols, glycols, ketones, ethers, esters, hydrocarbons, and various other organic solvents can be used, but alcohols are preferably used. These organic solvents may be used alone or in combination of two or more. As the alcohol, methanol, ethanol, isopropyl alcohol, and the like are preferable in terms of handleability and storage stability.
In addition, in the catalyst solution, it is preferable that the catalyst component is dissolved in the solvent.

As a method of spraying the catalyst solution while centrifugally floating and flowing, there is a method using a centrifugal floating and fluidized coating apparatus equipped with a rotor, an air path, and a spraying means.
Here, examples of the centrifugal floating fluid type coating apparatus include the apparatuses shown in FIGS. 1A and 1B.

Here, the centrifugal floating-flow device 200 shown in FIG. In order to supply the high-pressure air introduced from the chamber 22 from the vertical downward direction, slits 30 provided uniformly on the outer circumference of the bottom of the rotor 20 between the rotor 20 and the stator 21, and the particulate carrier A On the other hand, it is provided with a spray device 40 as a spraying part for spraying a catalyst solution and a product discharge port 60 as a catalyst carrier discharge port for discharging a catalyst carrier with a catalyst layer formed thereon. In addition, the slit 30 functions as a "floating flow section for causing the particulate carriers A to float and flow in the vertical direction" and a "drying section for drying the particulate carriers A".

Further, the tumble flow device 300 shown in FIG. 1B includes, for example, a rotor 20 and a stator 21 as a centrifugal swirling flow section for centrifugally swirling flowing the particulate carrier A in the centrifugal swirling flow direction X at a predetermined number of revolutions, and an air chamber. In order to supply the high-pressure air introduced from 22 from the vertical downward direction, between the rotor 20 and the stator 21, a slit 30 provided constantly on the entire outer circumference of the bottom of the rotor 20, and the particulate carrier A A spray device 40 as a spray unit that sprays the catalyst solution by using a spray device 40, and a stirring force (swirling force) in the same direction or the opposite direction (opposite direction in FIG. 1B) as the centrifugal swirling flow direction X for the particulate carrier that is centrifugally swirling. and a stirring unit 50 for imparting In addition, the slit 30 functions as a "floating flow section for causing the particulate carriers A to float and flow in the vertical direction" and a "drying section for drying the particulate carriers A".

<Centrifugal swirling flow section>
A rotor 20 as a centrifugal swirling flow section has a disk 23 horizontally arranged on the inner peripheral side of a cylindrical stator 21 and a rotating shaft 24 for rotating the disk 23 . The rotation shaft 24 of the rotor 20 and the central axis of the stator 21 are usually coaxially arranged.
The rotor 20 and the stator 21 as the centrifugal swirl flow section cause the particulate carriers A to undergo centrifugal swirl flow at a predetermined number of revolutions, so that the particulate carriers A can be uniformly dispersed.
In addition, by inclining the stator 21 with respect to the vertical direction, the amount of the particulate carriers A that can be processed can be increased.

<Floating flow part>
The slit 30 as a floating flow part supplies high-pressure air introduced from the air chamber 22 from the vertically downward direction to the particulate carriers A that are centrifugally swirling and flowing, thereby removing the particulate carriers A that are centrifugally swirling. The mixing circulation property of the particulate carriers A can be improved by causing them to float and flow in the vertical direction.
In addition, the floating flow part is not limited to the slit 30. For example, an air nozzle (not shown) that supplies high-pressure air from the vertically downward direction, a rotating plate (baffle plate) installed inside the lower part of the stator 21 ; not shown). By installing an air nozzle or a rotating plate instead of installing the slit 30, the particulate carrier A can be made to float and flow in the vertical direction, and a sufficient stirring effect can be obtained. The fluidity of the particulate carriers A can be further improved by using the slits 30 or air nozzles together with the rotary plate.

<Spraying part>
The spray device 40 as a spraying unit sprays the catalyst solution onto the particulate carriers A that are centrifugally floating and flowing, so that the particulate carriers A can be uniformly coated with the catalyst solution.
If the spray device 40 as the atomizing section is equipped with a constant flow rate pump, the catalyst solution can be sent quantitatively and the flow rate can be easily controlled. In addition, when the spray device 40 as the spray unit is equipped with an automatic spray gun, fine and uniform mist can be spray-coated, and as a result, a precise coating with a small particle size generation rate and a uniform particle diameter can be obtained. can be implemented.

<Dry section>
The slit 30 as the drying section supplies high-pressure air introduced from the air chamber 22 to the particulate carrier A from the vertical downward direction, thereby forming a coating film of the catalyst solution sprayed by the spray device 40 as the spraying section. The coated particulate carrier A can be dried.

The commercially available apparatus having the above-described configuration is not particularly limited and can be appropriately selected according to the purpose. Coating device (spira flow)” and the like are preferably exemplified.

<Catalyst layer forming step>
In the catalyst layer forming step of the method for producing a catalyst carrier of the present invention, a catalyst carrier having a uniform catalyst layer formed on the surface of the particulate carrier can be obtained by using a particulate carrier sprayed with a catalyst solution. can. Specifically, the catalyst solution adhering to the surface of the particulate carrier is dried (drying step) and optionally calcined (calcining step) to form a catalyst layer on the surface of the particulate carrier. A support can be obtained.
Here, drying is not particularly limited, and may be performed using a gas for causing the particulate carrier to float and flow. In addition, it is preferable to perform drying above the dew point and below 100 degreeC. By performing drying at the dew point or higher, it is possible to prevent water from adhering to the particulate carrier.
Alternatively, the calcination may be carried out using a fluidized bed or a rotary kiln after the particles obtained by drying the sprayed catalyst solution are removed from the centrifugal floating fluidized device. Note that the firing is preferably performed in an oxygen atmosphere. Also, the firing temperature is preferably about 300° C. or higher. The baking time is preferably 5 minutes or more and 60 minutes or less, more preferably 5 minutes or more and 40 minutes or less. For example, a coating containing an aluminum catalyst needs to be baked at 300°C or higher, and a coating containing an iron catalyst needs to be baked at 80°C or higher.
Incidentally, the thickness of the catalyst layer is usually in the range of 0.1 nm to 100 nm. The aluminum catalyst functions as a promoter, and the thickness of the layer containing the aluminum catalyst is preferably 10 nm or more and 100 nm or less, and the iron catalyst functions as a catalyst, and the thickness of the layer containing the iron catalyst is 0.1 nm or more and 10 nm. The following are preferable.

<Stirring process>
In the method for producing a catalyst carrier of the present invention, a stirring force (swirling force) in the same direction as or opposite to the direction of centrifugal swirl flow is applied to the particulate carrier undergoing centrifugal suspension flow during the centrifugal suspension flow step. Thereby, the stirring efficiency of the particulate carrier can be improved.
The stirring unit 50 has an agitator 51 horizontally arranged on the inner peripheral side of the disc 23 and a rotating shaft 52 for rotating the agitator 51 . The rotating shaft 24 of the rotor 20 and the rotating shaft 52 that rotates the agitator 51 are usually arranged coaxially.
The stirring part 50 may further have stirring blades or baffles arranged substantially horizontally from the side surface of the conical agitator 51 .
The stirring unit 50 applies a stirring force (swirling force) in the same direction or opposite direction to the centrifugal swirling flow direction X to the particulate carriers A that are centrifugally suspended and flowed, thereby further improving the stirring efficiency of the particulate carriers A. can be made

When forming a plurality of catalyst layers on the surface of the particulate carrier, in addition to the above-described steps, the following centrifugal floating flow step, other spraying step, and other catalyst layer forming step are performed, A plurality of catalyst layers can be formed on the surface of the particulate support (for example, FIGS. 2, 3 and 5, described below).

<Other centrifugal floating flow processes>
In another centrifugal floating flow step of the method for producing a catalyst carrier according to the present invention, the primary catalyst particles having a catalyst layer formed on the surface obtained in the catalyst layer forming step are caused to undergo centrifugal swirling flow and floating flow in the vertical direction. Thus, the primary catalyst particles can be helically rolled or rotated (revolved) to be efficiently stirred.
The other centrifugal floating flow process can be performed in the same manner as the centrifugal floating flow process described above.

<Other spraying processes>
In the other spraying step of the method for producing a catalyst carrier of the present invention, the catalyst solution is sprayed onto the primary catalyst particles that are centrifugally floating and flowing in the other centrifugal floating and flowing step, so that the catalyst solution is sprayed onto the surfaces of the primary catalyst particles. A coating film can be uniformly formed from the solution.
Other spraying steps can be carried out in the same manner as the spraying step described above.

<Other catalyst layer forming steps>
In another catalyst layer forming step of the method for producing a catalyst carrier of the present invention, a uniform catalyst layer can be further formed on the surface of the primary catalyst particles by using the primary catalyst particles sprayed with the catalyst solution.

A specific example of the procedure for producing the catalyst support itself using the above-described method is shown below. In addition, it is not limited to the following specific examples, and firing may not be performed, and a one-layer structure may be used.
FIG. 2 is a diagram for explaining the case of producing a catalyst carrier having a structure of particulate carrier/aluminum oxide layer/iron catalyst layer using the method for producing a catalyst carrier according to the present invention.
In FIG. 2, first, a particulate carrier 1 is prepared (FIG. 2(a)). Next, while centrifugally floating and flowing the prepared particulate carrier 1, an aluminum catalyst-containing solution as a catalyst solution is sprayed (spraying step) and dried to form a coating film 2 containing an aluminum catalyst, A coated particulate carrier 3 having a coated film 2 formed on the surface thereof is produced (FIG. 2(b)). Next, the coated particulate carrier 3 having the coated film 2 formed on the surface was calcined to form an aluminum oxide (Al ₂ O ₃ ) layer 4 (catalyst layer) on the surface of the particulate carrier 1. Primary catalyst particles 5 are produced (catalyst layer forming step; FIG. 2(c)). Finally, an iron-containing solution as a catalyst solution is sprayed while centrifugally floating and flowing the primary catalyst particles 5 (another spraying process), and dried to form a coating film 6 (catalyst layer) containing an iron catalyst on the surface. is obtained (another step of forming a catalyst layer; FIG. 2(d)).

FIG. 3 is a diagram for explaining the case of producing a catalyst carrier having a structure of particulate carrier/aluminum oxide layer/iron oxide layer using the method for producing a catalyst carrier according to the present invention.
In FIG. 3, first, a particulate carrier 1 is prepared (FIG. 3(a)). Next, while centrifugally floating and flowing the prepared particulate carrier 1, an aluminum catalyst-containing solution as a catalyst solution is sprayed (spraying step) and dried to form a coating film 2 containing an aluminum catalyst, A coated particulate carrier 3 having a coated film 2 formed on the surface thereof is produced (FIG. 3(b)). Next, the coated particulate carrier 3 having the coated film 2 formed on the surface is calcined to prepare the primary catalyst particles 5 having the aluminum oxide layer 4 formed on the surface of the particulate carrier 1 (catalyst layer Forming step; FIG. 3(c)). Next, an iron-containing solution as a catalyst solution was sprayed while centrifugally floating and flowing the primary catalyst particles 5 (another spraying process), and dried to form a coating 6 containing an iron catalyst on the surface. Primary catalyst particles 7 with a coating film are obtained (FIG. 3(d)). Finally, the coated primary catalyst particles 7 are calcined to obtain a catalyst carrier 11 having an iron oxide layer 10 (catalyst layer) formed on the surface of the primary catalyst particles 5 (another catalyst layer forming step; FIG. (e)).

FIG. 4 is a diagram for explaining the case of producing a catalyst carrier having a structure of a particulate carrier/catalyst layer composed of aluminum oxide and iron oxide using the method for producing a catalyst carrier according to the present invention.
In FIG. 4, first, a particulate carrier 1 is prepared (FIG. 4(a)). Next, a catalyst solution containing an aluminum catalyst and an iron catalyst is sprayed while centrifugally floating and flowing the prepared particulate carrier 1 (spraying step), and dried to form a coating film 12 containing an aluminum catalyst and an iron catalyst. is formed to produce a coated particulate carrier 13 (FIG. 4(b)). Next, the coated particulate carrier 13 is calcined to obtain primary catalyst particles 15 (catalyst carrier) in which a catalyst layer 14 containing aluminum oxide and iron oxide is formed on the surface of the particulate carrier 1 (catalyst Layer forming step; FIG. 4(c)).

FIG. 5 is for explaining the case of producing a catalyst carrier having a structure of particulate carrier/catalyst layer composed of aluminum oxide and iron oxide/iron oxide layer using the method for producing a catalyst carrier according to the present invention. It is a diagram.
In FIG. 5, first, a particulate carrier 1 is prepared (FIG. 5(a)). Next, a catalyst solution containing an aluminum catalyst and an iron catalyst is sprayed while centrifugally floating and flowing the prepared particulate carrier 1 (spraying step), and dried to form a coating film 12 containing an aluminum catalyst and an iron catalyst. is formed to produce a coated particulate carrier 13 (FIG. 5(b)). Next, the coated particulate carrier 13 is calcined to obtain primary catalyst particles 15 in which a catalyst layer 14 containing aluminum oxide and iron oxide is formed on the surface of the particulate carrier 1 (catalyst layer forming step; FIG. 5(c)). Next, while centrifugally floating and flowing the primary catalyst particles 15, an iron-containing solution is sprayed as a catalyst solution (another spraying process), and dried to form a coating film 16 containing an iron catalyst. A membrane-coated primary catalyst particle 17 is produced (FIG. 5(d)). Finally, the coated primary catalyst particles 17 are calcined to produce a catalyst carrier 19 in which an iron oxide layer 18 is formed as a catalyst layer on the surface of the primary catalyst particles 15 (another catalyst layer forming step; FIG. 5 (e)).

(Manufacturing method of fibrous carbon nanostructure)
A method for producing a fibrous carbon nanostructure of the present invention is a method for producing a fibrous carbon nanostructure. In the method for producing a fibrous carbon nanostructure of the present invention, a raw material gas is supplied to the catalyst carrier obtained by the method for producing a catalyst carrier of the present invention, and fibrous carbon nanostructures are produced on the catalyst layer. A step of synthesizing the structure (synthesis step) is included.

<Fibrous carbon nanostructure>
The fibrous carbon nanostructure is not particularly limited, and includes, for example, a fibrous carbon nanostructure having an aspect ratio of more than 10. Specifically, fibrous carbon nanostructures include CNTs, vapor-grown carbon fibers, and the like.
In the present invention, the "aspect ratio of fibrous carbon nanostructures" is measured by measuring the diameter (outer diameter) and length of 100 randomly selected fibrous carbon nanostructures using a transmission electron microscope. can be asked for.
A case where the fibrous carbon nanostructure obtained by the production method of the present invention contains CNTs will be described below, but the present invention is not limited to this.

<<Carbon Nanotube>>
CNT is a material having a structure in which a graphene sheet is rolled into a cylinder and has a one-dimensional structure with a very large aspect ratio (see Non-Patent Document 1). Here, the fibrous carbon nanostructures containing CNTs may be composed of CNTs alone, or may be a mixture of CNTs and fibrous carbon nanostructures other than CNTs.

In addition, the CNT is not particularly limited, and can be a single-walled carbon nanotube and/or a multi-walled carbon nanotube. The CNT is preferably composed of 10 or less layers, more preferably 5 or less layers, and still more preferably single-walled carbon nanotubes. Single-walled carbon nanotubes/multi-walled carbon nanotubes can be appropriately adjusted by changing various reaction conditions such as catalyst size, catalyst composition, reaction time, source gas supply flow rate, and the like.

[Properties]
In addition, the average diameter of fibrous carbon nanostructures containing CNTs can be set to desired values according to various uses. For example, if the particle diameter of the metal fine particles in the catalyst is about 1 nm or more and 2 nm or less, the average diameter of the CNTs is about 1 nm, and if the metal fine particles have a particle diameter of about 30 nm, the average diameter of the CNTs is about 30 nm. The diameter can be adjusted to approximately 20 nm or more and 30 nm or less. In general, the finer the average diameter of CNTs, the better various properties.
The "average diameter" of fibrous carbon nanostructures containing CNTs is obtained by, for example, measuring the diameter (outer diameter) of 100 randomly selected fibrous carbon nanostructures using a transmission electron microscope. can ask.

In addition, the average length of the fibrous carbon nanostructure containing CNTs can be set to a desired value according to various uses, but the average length at the time of synthesis is preferably 1 μm or more, and is 50 μm or more. is more preferable. If the average length of the fibrous carbon nanostructure containing CNTs at the time of synthesis is 1 μm or more, the resulting fibrous carbon nanostructure has various properties such as mechanical strength, electrical properties, and thermal conductivity. It is because it can be exhibited more satisfactorily. In addition, the longer the fibrous carbon nanostructure including CNTs during synthesis, the more likely the fibrous carbon nanostructure is to be damaged such as fracture or cut. The average length of the structures is preferably 5000 μm or less.
The "average length" of fibrous carbon nanostructures containing CNTs can be appropriately adjusted, for example, by changing the synthesis reaction time.

<Synthesis process>
In the method for producing a fibrous carbon nanostructure of the present invention, a raw material gas is supplied to the catalyst carrier obtained by the method for producing a catalyst carrier of the present invention, and the fibrous carbon nanostructure is produced on the catalyst layer. For example, a raw material gas is supplied to the outermost catalyst layer of the catalyst carrier obtained by the method for producing a catalyst carrier of the present invention to form a fibrous carbon nanostructure on the catalyst layer. By generating and growing the generated fibrous carbon nanostructures by chemical vapor deposition, fibrous carbon nanostructures such as carbon nanotubes can be synthesized and grown with high efficiency, and are excellent in mass productivity.
In the synthesis step, at least one of the catalyst layer and the raw material gas is usually heated. From the viewpoint of growing the fibrous carbon nanostructures with a uniform density, it is preferable to heat at least the raw material gas. The heating temperature is preferably 400° C. or higher and 1100° C. or lower. In the synthesis step, a raw material gas, optionally an inert gas, a reducing gas, and/or a catalyst activating substance are introduced into a fibrous carbon nanostructure growth furnace containing a catalyst carrier.

From the viewpoint of increasing the production efficiency of fibrous carbon nanostructures, it is preferable to supply the reducing gas and the raw material gas to the catalyst in the catalyst layer by gas shower.

-raw material gas-
As the raw material gas, a gaseous substance containing a carbon source is used at a temperature at which the fibrous carbon nanostructure grows. Among them, hydrocarbons such as methane, ethane, ethylene, propane, butane, pentane, hexane, heptane, propylene and acetylene are preferred. In addition, lower alcohols such as methanol and ethanol, and oxygen-containing compounds with a low carbon number such as acetone and carbon monoxide may be used. Mixtures of these can also be used.

-Inert gas-
The raw material gas may be diluted with an inert gas. The inert gas may be any gas that is inert at the temperature at which the fibrous carbon nanostructures grow and that does not react with the growing fibrous carbon nanostructures, and preferably does not reduce the activity of the catalyst. . Examples include rare gases such as helium, argon, neon and krypton; nitrogen; hydrogen; and mixed gases thereof.

-Reducing gas-
Hydrogen gas, ammonia, water vapor, and mixed gases thereof can be used as the reducing gas, for example. Also, the reducing gas may be a mixed gas in which hydrogen gas is mixed with an inert gas such as helium gas, argon gas, or nitrogen gas.

- Catalyst activation material -
A catalyst activation material may be added in the step of growing the fibrous carbon nanostructure. Addition of the catalyst activation material can further improve the production efficiency and purity of the fibrous carbon nanostructure. The catalyst activation material used here is generally a material containing oxygen, and is preferably a material that does not significantly damage the fibrous carbon nanostructures at the temperature at which the fibrous carbon nanostructures grow. For example, low carbon number oxygenated compounds such as water, oxygen, ozone, acid gases, nitrogen oxides, carbon monoxide and carbon dioxide; alcohols such as ethanol and methanol; ethers such as tetrahydrofuran; ketones such as acetone; Aldehydes; esters; and mixtures thereof are effective. Among these, water, oxygen, carbon dioxide, carbon monoxide, and ethers are preferred, and water is particularly preferred.

The volume concentration of the catalyst activating substance is not particularly limited, but is preferably a very small amount.

-Other conditions-
The pressure in the reactor and the processing time in the growth step may be appropriately set in consideration of other conditions. For example, the pressure is 1×10 ² Pa to 1×10 ⁷ Pa, and the processing time is 1 minute or longer. It can be about 60 minutes or less.

Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Example 1)
<Production of catalyst carrier>
750 g of zirconia beads (ZrO _2, volume average particle diameter D50: 300 μm) as a particulate carrier are placed in a centrifugal floating flow device (“CF-LABO” manufactured by Freund Corporation), and centrifuged as shown in FIG. 1A. An aluminum catalyst containing 1.2 g of aluminum as a catalyst with respect to isopropyl alcohol (IPA) (500 g) as a solvent while floating and flowing (rotor rotation speed 300 rpm, slit air supply rate 45 L/min, slit air temperature 50 ° C.) Spray the solution with a spray gun (spray amount 3 g / min), spray time 950 seconds, spray air pressure 10 MPa), and after spraying, slit air (temperature 50 ° C.) is further supplied (45 L / min for 180 seconds). , and dried to form a coating of the aluminum catalyst solution on the zirconia beads. Next, a calcination treatment was performed at 480° C. for 45 minutes to obtain primary catalyst particles (FIG. 3(c)) on which an aluminum oxide layer was formed.
Furthermore, while centrifugally floating and flowing the obtained primary catalyst particles (rotor rotation speed 300 rpm, slit air supply amount 45 L / min, slit air temperature 50 ° C.), iron as a catalyst was added to IPA (170 g) as a solvent. An iron catalyst solution containing 90 mg is sprayed with a spray gun (spray amount 3 g / min, spray time 350 seconds, spray air pressure 10 MPa), and after spraying, slit air (temperature 50 ° C.) is further supplied (45 L / min for 180 seconds ) to dry and form a coating of the iron catalyst solution on the primary catalyst particles. Next, a calcination treatment was performed at 170° C. for 20 minutes to obtain primary catalyst particles (catalyst carrier) (FIG. 3(e)) further formed with an iron oxide layer.

<Synthesis of carbon nanotubes>
20.0% by volume-ethylene gas ( _{C.sub.2H.sub.4} )/10% by volume--hydrogen gas ( _H.sub.2 )/70% by volume--nitrogen gas ( _{N.sub.2 )} with respect to the catalyst carrier obtained above. The raw material gas was supplied into the reaction tube for 10 minutes at a total flow rate of 1500 sccm under normal pressure and a temperature of 850°C. By supplying the raw material gas in this manner, carbon nanotubes were synthesized on the catalyst carrier by a fluidized bed method in which the catalyst carrier was fluidized.
Using the catalyst carrier on which carbon nanotubes were synthesized, the production yield of carbon nanotubes was calculated according to the following method. As a result, the production yield of carbon nanotubes was 10%.
<<Production Yield Y of Carbon Nanotubes>>
The weight G _c-source (g) of the carbon raw material contained in the ethylene supplied to the reaction field, the total supply flow rate F (sccm) of the raw material gas, the ethylene concentration C _C2H4 (% by volume), the reaction time t (minutes), Using the standard gas molar volume V=22400 (cc/mol) and the molar mass of carbon M≈12 (g/mol), the following formula (I):
G _c-source (g)=
F×( _CC2H4 /100)×t×(1/V)×(M×2) (I)
Calculated according to
Next, the yield G _CNT (g) of the carbon nanotubes synthesized on the catalyst of the catalyst carrier was weighed using an electronic balance (manufactured by Shimadzu Corporation, model number “AUW120D”). The G _CNT was obtained by subtracting the mass of the catalyst carrier from the total mass of the catalyst carrier on which the carbon nanotubes were synthesized. and the following formula (II):
Carbon nanotube production yield Y (%) =
(G _CNT /G _c-source )×100 (II)
Calculated according to A higher value of production yield Y indicates a higher production efficiency of carbon nanotubes.

(Example 2)
Synthesis of carbon nanotubes and calculation of the production yield of carbon nanotubes were performed in the same manner as in Example 1, except that the catalyst carrier was produced as follows. As a result, the production yield of carbon nanotubes was 4%.
<Production of catalyst carrier>
1800 g of zirconia beads (ZrO2 _, volume average particle diameter D50: 300 μm) as a particulate carrier were placed in a tumbling flow device (Freund Sangyo Co., Ltd., "Complex type fluidized bed granulation coating device (SPIRA FLOW)"). , As shown in FIG. 1B, while centrifugal floating flow (rolling flow) (rotor rotation speed 400 rpm, slit air supply amount 860 L / min, slit air temperature 40 ° C.), isopropyl alcohol (IPA) (500 g) as a solvent is sprayed with an aluminum catalyst solution containing 1.2 g of aluminum as a catalyst with a spray gun (spray amount 10 g / min), spray time 600 seconds, spray air pressure 36 MPa), after spraying, slit air (temperature 40 ° C) (860 L/min for 120 seconds) to dry and form a coating of the aluminum catalyst solution on the zirconia beads. Next, a calcination treatment was performed at 480° C. for 45 minutes to obtain primary catalyst particles (FIG. 3(c)) on which an aluminum oxide layer was formed.
Furthermore, while the obtained primary catalyst particles are subjected to centrifugal floating flow (rolling flow) (rotor rotation speed 400 rpm, slit air supply amount 860 L / min, slit air temperature 40 ° C.), IPA (170 g) as a solvent An iron catalyst solution containing 90 mg of iron as a catalyst is sprayed with a spray gun (spray amount 30 g/min, spray time 520 seconds, spray air pressure 36 MPa), and after spraying, slit air (temperature 40 ° C.) is further supplied (860 L). /min for 120 seconds) to dry and form a coating of the iron catalyst solution on the primary catalyst particles. Next, a calcination treatment was performed at 170° C. for 20 minutes to obtain primary catalyst particles (catalyst carrier) (FIG. 3(e)) further formed with an iron oxide layer.

(Comparative example 1)
Synthesis of carbon nanotubes and calculation of the production yield of carbon nanotubes were performed in the same manner as in Example 1, except that the catalyst carrier was produced as follows. As a result, the production yield of carbon nanotubes was 2%.
<Production of catalyst carrier>
150 g of zirconia beads (ZrO2 _, volume average particle size D50: 320 μm) as a particulate support are immersed in an aluminum catalyst solution containing 1.2 g of aluminum as a catalyst in IPA (500 g) as a solvent (immersion Time 20 seconds) and air (temperature 45° C.) was supplied (at 50 L/min for 1000 seconds) to dry and form a coating film of the aluminum catalyst solution on the zirconia beads. Next, a calcination treatment was performed at 480° C. for 30 minutes to obtain primary catalyst particles on which an aluminum oxide layer was formed.
Furthermore, the obtained primary catalyst particles are immersed in an iron catalyst solution containing 90 mg of iron as a catalyst in IPA (170 g) as a solvent (immersion time: 20 seconds), and air (temperature: 45°C) is supplied ( 50 L/min for 1000 seconds) to dry and form a coating of the iron catalyst solution on the primary catalyst particles. Next, a calcination treatment was performed at 170° C. for 20 minutes to obtain primary catalyst particles (catalyst carrier) further formed with an iron oxide layer.

In Examples 1 and 2, compared with Comparative Example 1, the production efficiency of carbon nanotubes is high. From this, in Examples 1 and 2, compared with Comparative Example 1, it can be seen that the catalyst layer can be formed more uniformly on the surface of the particulate carrier.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the catalyst carrier which can form a catalyst layer uniformly on the surface of a particulate carrier can be provided.
Moreover, according to the present invention, it is possible to synthesize fibrous carbon nanostructures such as carbon nanotubes with high efficiency, and to provide a method for producing fibrous carbon nanostructures that is excellent in mass productivity.

1 Particulate carrier 2 Coated film 3 Coated particulate carrier 4 Aluminum oxide layer 5 Primary catalyst particles 6 Coated film 7 Coated primary catalyst particles 10 Iron oxide layer 11 Catalyst carrier 12 Coated film 13 Coated particulate carrier 14 Catalyst layer 15 Primary catalyst particles 16 Coating film 17 Coated primary catalyst particles 18 Iron oxide layer 19 Catalyst carrier 20 Rotor 21 Stator 22 Air chamber 23 Disk 24 Rotating shaft 30 Slit 40 Spray device 50 Stirrer 51 Agitator 52 Rotating shaft 60 Product discharge port 200 Centrifugal floating flow device 300 Rolling flow device A Particulate carrier X Direction of centrifugal swirling flow

Claims (9)

A method for producing a catalyst carrier used in producing a fibrous carbon nanostructure, comprising:
a centrifugal floating flow step in which the particulate carriers are caused to float and flow in the vertical direction while being centrifugally swirled;
a spraying step of spraying a catalyst solution onto the particulate carrier centrifugally floating and flowing in the centrifugal floating and flowing step to form a coating film made of the catalyst solution on the surface of the particulate carrier ;
a catalyst layer forming step of drying the coating film and forming a catalyst layer on the surface of the particulate carrier. 2. The method for producing a catalyst carrier according to claim 1, wherein the floating flow is to supply a gas to the particulate carrier to cause the carrier to float in the vertical direction. 3. The method for producing a catalyst carrier according to claim 1, further comprising a stirring step of imparting a stirring force in the same direction or in a direction opposite to the direction of centrifugal swirl flow to said centrifugally floating and flowing particulate carrier. 4. The method for producing a catalyst carrier according to claim 1, wherein said particulate carrier has a porosity of 10% or less and is composed of a metal oxide. 5. The method for producing a catalyst carrier according to claim 4, wherein said metal oxide is zirconium dioxide, aluminum oxide or zircon. Any one of claims 1 to 5, wherein in the catalyst layer forming step, the coating film is heated to a temperature of 300 ° C. or higher using a fluidized bed or a rotary kiln to form a catalyst layer on the surface of the particulate carrier. A method for producing the described catalyst support. 7. The method for producing a catalyst carrier according to claim 1, wherein said catalyst solution contains at least one metal selected from Fe, Mo, Co and Al. Another centrifugal floating flow step in which the primary catalyst particles having the catalyst layer formed on the surface obtained in the catalyst layer forming step are caused to undergo centrifugal swirl flow and floating flow in the vertical direction;
another spraying step of spraying a catalyst solution onto the centrifugally floating and flowing primary catalyst particles in the other centrifugal floating and flowing step to form a coating film made of the catalyst solution on the surface of the primary catalyst particles;
8. The method for producing a catalyst carrier according to any one of claims 1 to 7, further comprising another catalyst layer forming step of drying the coating film and further forming a catalyst layer on the surface of the primary catalyst particles. A step of synthesizing a fibrous carbon nanostructure on the catalyst layer by supplying a raw material gas to the catalyst carrier obtained by the method for producing a catalyst carrier according to any one of claims 1 to 8. A method for producing a fibrous carbon nanostructure, comprising:

Images