JP2002234715A - Method for producing fullerenes and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing fullerenes by which fullerenes, particularly carbon nanotubes can easily be produced in large quantities in a high yield. SOLUTION: In the method for producing fullerenes, arc discharge 5 is caused between a pair of carbon rod electrodes 2, 3 in a reaction chamber 1 held in an atmosphere of an inert gas under reduced pressure and a product containing formed fullerenes is carried by the inert gas, led to a gas circulation passage 6 connected to the reaction chamber and collected by a filter 11 disposed in the gas circulation passage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for producing fullerenes, and more particularly, to a method for producing fullerenes, particularly carbon nanotubes.
The present invention relates to a method and an apparatus for producing fullerenes which can be produced in a large amount, easily and with a high yield.

[0002]

2. Description of the Related Art Carbon nanotubes are allotropes of carbon and are formed by nesting a plurality of cylinders each having a rounded graphitic carbon atom surface having a thickness of several atomic layers and having a diameter of about 0.5 nm or less. It is a fine material having a length of about several μm and a thickness of about 10 nm.

[0003] It has been theoretically clarified that the electronic properties of carbon nanotubes change from metallic properties to semiconducting properties due to the way of spiraling, that is, so-called chirality.

[0004] Therefore, carbon nanotubes are regarded as promising as next-generation electronic materials, and in particular, nanoelectronic materials, highly-directed radiation sources, soft X-ray sources, one-dimensional conductive materials, high thermal conductive materials, and hydrogen storage materials. Applications to such applications are expected. By adding treatments such as surface functionalization, metal coating, and inclusion of foreign substances, the use of carbon nanotubes is expected to be further expanded.

[0005] Therefore, there is a demand for the development of a method capable of easily producing a large amount of carbon nanotubes in a high yield.

On the other hand, fullerene which is an allotrope of carbon is also used as a photoreceptor, a photoelectric conversion element, a solar cell, an optical limiter, a toner, a nonlinear optical element, a switching element, a superconductor, a transistor, a Josephson element, a sensor, a diode, It is expected to be applied to catalysts, emitters, and the like, and development of a method that can be mass-produced easily and in high yield in the same manner as carbon nanotubes is desired.

[0007] Conventionally, carbon nanotubes have been obtained by irradiating a mixture of carbon and a catalyst metal such as cobalt with a laser in an inert gas atmosphere under reduced pressure to evaporate the carbon and to form a cooled needle-like material. Laser ablation method to grow carbon nanotubes on top, CVD
Using a carbon rod as an electrode, an arc discharge is performed in an inert gas atmosphere under reduced pressure, and an arc discharge method of growing carbon nanotubes on the carbon rod is used. Among them, the arc discharge method is widely used because it is suitable for mass synthesis of carbon nanotubes.

[0008]

However, when synthesizing carbon nanotubes by the arc discharge method, there are problems that the yield is low and that it takes time to remove impurities by purification.

That is, when synthesizing carbon nanotubes by the arc discharge method, an arc discharge is generated between a cathode composed of a pure carbon electrode and an anode composed of an electrode added with a metal such as iron, cobalt, nickel or lanthanum. When generated, the metal and carbon evaporate simultaneously from the anode, and the evaporated carbon forms soot, but since the evaporated metal acts as a catalyst, the soot formed
Carbon nanotubes are generated. According to this arc discharge method, a large amount of soot containing carbon nanotubes can be synthesized, but a part of the evaporated carbon grows on the cathode as a deposit, resulting in a yield of carbon nanotubes. There is a problem that can not be improved.

[0010] In addition to carbon nanotubes, graphite, amorphous carbon,
Since it contains impurities such as catalyst metals and oxides of catalyst metals, it is necessary to remove impurities by purification,
Purification is usually carried out by removing a catalytic metal with an acidic solution such as nitric acid and removing amorphous carbon and graphite by treating with air or oxygen, but 1 g containing 10 to 40% by weight of carbon nanotubes. At present, it takes three days or more to purify soot, and there is a problem that carbon nanotubes cannot be efficiently obtained.

Accordingly, an object of the present invention is to provide a method and an apparatus for producing fullerenes, in particular, carbon nanotubes which can be produced in a large amount, easily and with high yield. It is.

[0012]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
In a reaction chamber held in a reduced pressure atmosphere of an inert gas, an arc discharge is generated between a pair of carbon rod electrodes,
The product containing the generated fullerenes is introduced into the gas circulation passage connected to the reaction chamber while being accompanied by the inert gas, and collected by a filter provided in the gas circulation passage. This is achieved by a method for producing fullerenes, which is a feature.

According to the present invention, a product released in a web-like or flocculent manner upward from a portion where an arc discharge is generated is a fullerene, particularly, a potentially wide-ranging application. Is based on the finding that the purity of the expected carbon nanotubes is high, and according to the present invention, from the part where the arc discharge is generated, upward,
Fullerenes released in a spider web or flocculent form, in particular, high-purity products of carbon nanotubes, are accompanied by an inert gas and led to a gas circulation path connected to the reaction chamber. By collecting with a filter provided therein, it is possible to efficiently collect, and it is possible to produce fullerenes, particularly carbon nanotubes, in a large amount, easily and with high yield.

[0014] In a preferred embodiment of the present invention, an arc discharge is generated between a pair of carbon rod electrodes, and the product containing fullerenes formed in a spider web or floc is removed by the inert gas. Is guided to a gas circulation passage connected to the reaction chamber, and collected by a filter provided in the gas circulation passage.

According to a preferred embodiment of the present invention, fullerenes, particularly carbon nanotubes having a high purity, are emitted upward from the part where the arc discharge is generated in a spider web or cotton form. An object can be efficiently collected, and fullerenes, in particular, carbon nanotubes can be produced in a large amount, easily, and in a high yield.

In a further preferred aspect of the present invention, the product containing fullerenes contains carbon nanotubes.

According to a further preferred embodiment of the present invention, carbon nanotubes, which are potentially expected to be applied in a wide range of fields, can be produced in a large amount, simply, and in a high yield. .

In a further preferred embodiment of the present invention, the product including the fullerenes is guided to the circulation passage together with the inert gas by a fan.

According to a further preferred embodiment of the present invention, an inert gas is circulated in the gas circulation passage by a fan, and a spider web or cotton is formed upward from the portion where the arc discharge is generated. Fullerenes introduced into the gas circulation path, particularly products with high purity of carbon nanotubes, are collected by the filter provided in the gas circulation path. Therefore, fullerenes, particularly products with high purity of carbon nanotubes, can be efficiently collected, and fullerenes, especially carbon nanotubes, can be produced in large quantities, easily and with high yield. It becomes possible.

In still another preferred embodiment of the present invention, the product including the fullerenes is guided to the circulation path together with the inert gas by a pump.

According to yet another preferred embodiment of the present invention, the inert gas is circulated in the gas circulation passage by the pump, and the spider web is formed upward from the portion where the arc discharge is generated. Alternatively, fullerenes released in a flocculent form and guided into the gas circulation passage by the inert gas, and particularly, products having a high purity of carbon nanotubes are captured by a filter provided in the gas circulation passage. Since it is collected, fullerenes, particularly products with high purity of carbon nanotubes, can be efficiently collected, and fullerenes, particularly carbon nanotubes, can be collected in large quantities, easily and with high yield. It can be manufactured.

In a further preferred aspect of the present invention, of the pair of carbon rod electrodes, a carbon rod electrode serving as a positive electrode contains a catalyst metal.

In a further preferred embodiment of the present invention, the catalyst metal is Co, Ni, Sc, V, Cr, M
n, Fe, Cu, Y, Zr, Nb, Mo, Pd, Ta,
W, Au, Th, U, La, Ce, Pr, Nd, Gd,
It is composed of one or more metals selected from the group consisting of Tb, Dy, Ho, Er, Tm and Lu.

According to a further preferred embodiment of the present invention, of the pair of carbon rod electrodes, the carbon rod electrode serving as a positive electrode is made of Co, Ni, Sc, V, Cr, Mn, Fe, Cu,
Y, Zr, Nb, Mo, Pd, Ta, W, Au, Th,
U, La, Ce, Pr, Nd, Gd, Tb, Dy, H
Since it contains a catalytic metal consisting of one or more metals selected from the group consisting of o, Er, Tm and Lu,
Metal-encapsulated fullerenes containing these catalyst metals can be efficiently produced.

Another object of the present invention is to provide a reaction chamber maintained in a reduced-pressure atmosphere of an inert gas, a pair of carbon rod electrodes provided in the reaction chamber, and a gas connected to the reaction chamber. A circulation passage, comprising: a gas circulation means for circulating the inert gas through the reaction chamber and the gas circulation passage;
This is achieved by a fullerenes manufacturing apparatus characterized by including a filter.

According to the present invention, an apparatus for producing fullerenes is connected to a reaction chamber maintained in a reduced pressure atmosphere of an inert gas, a pair of carbon rod electrodes provided in the reaction chamber, and the reaction chamber. A gas circulation path, and an inert gas, comprising a gas circulation means for circulating in the reaction chamber and the gas circulation path, since a filter is provided in the circulation path, from the portion where arc discharge is generated,
Upward, fullerenes released in the form of cobwebs or flocculents, in particular, products of high purity of carbon nanotubes, are entrained in an inert gas into a gas circulation passage connected to the reaction chamber. Guided and collected by a filter provided in the gas circulation passage, it is possible to efficiently collect the fullerenes, particularly carbon nanotubes, in a large amount, easily and with a high yield.
It can be manufactured.

In a preferred embodiment of the present invention, the gas circulation means is constituted by a fan.

According to a preferred embodiment of the present invention, an inert gas is circulated in the gas circulation passage by a fan, and upward from a portion where the arc discharge is generated.
Fullerenes, which are released in a spider web or flocculent form and are entrained by the inert gas into the gas circulation path, particularly products with high purity of carbon nanotubes, are provided in the gas circulation path. Fullerenes, especially products with high carbon nanotube purity, can be efficiently collected,
Fullerenes, particularly carbon nanotubes, can be produced in large quantities, easily, and with high yield.

[0029] In another preferred embodiment of the present invention, the gas circulation means is constituted by a pump.

According to another preferred embodiment of the present invention,
By the pump, the inert gas is circulated in the gas circulation passage, and is discharged upward from the portion where the arc discharge is generated in a spider web or cotton form, accompanied by the inert gas, Fullerenes introduced into the gas circulation path, especially products with high purity of carbon nanotubes, are collected by the filter provided in the gas circulation path, so the purity of fullerenes, especially carbon nanotubes, is reduced. High products can be efficiently collected, and fullerenes, particularly carbon nanotubes, can be produced in large quantities, easily, and in high yield.

According to a further preferred embodiment of the present invention, the pair of carbon rod electrodes are arranged in a substantially horizontal plane such that respective ends thereof face each other.

In still another preferred embodiment of the present invention, the pair of carbon rod electrodes are arranged in a substantially vertical plane such that respective ends thereof face each other.

[0033] In a further preferred aspect of the present invention, the carbon rod electrode serving as a positive electrode of the pair of carbon rod electrodes contains a catalyst metal.

In a further preferred embodiment of the present invention, the catalyst metal is Co, Ni, Sc, V, Cr, M
n, Fe, Cu, Y, Zr, Nb, Mo, Pd, Ta,
W, Au, Th, U, La, Ce, Pr, Nd, Gd,
It is composed of one or more metals selected from the group consisting of Tb, Dy, Ho, Er, Tm and Lu.

According to a further preferred embodiment of the present invention, of the pair of carbon rod electrodes, the carbon rod electrode serving as a positive electrode is made of Co, Ni, Sc, V, Cr, Mn, Fe, Cu,
Y, Zr, Nb, Mo, Pd, Ta, W, Au, Th,
U, La, Ce, Pr, Nd, Gd, Tb, Dy, H
Since it contains a catalytic metal consisting of one or more metals selected from the group consisting of o, Er, Tm and Lu,
Metal-encapsulated fullerenes containing these catalyst metals can be efficiently produced.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a schematic side view of an apparatus for producing carbon nanotubes according to a preferred embodiment of the present invention.

As shown in FIG. 1, the apparatus for producing carbon nanotubes comprises a reaction chamber 1 held in an inert gas atmosphere under reduced pressure, a carbon rod electrode 2 acting as a positive electrode, and a carbon rod electrode 2 acting as a negative electrode. A rod electrode 3 is provided. A pair of carbon rod electrodes 2 and 3
, The longitudinal axes thereof are located substantially in a horizontal plane, and are arranged such that one ends thereof face each other. The other ends of the carbon rod electrode 2 and the carbon rod electrode 3 are respectively connected to a DC power supply 4 so that an arc discharge 5 can be generated between the pair of carbon rod electrodes 2 and 3. . Here, the carbon rod electrode 2 acting as a positive electrode has Co and Ni as catalysts when producing carbon nanotubes.
Is used.

As shown in FIG. 1, a gas circulation passage 6 is connected to the reaction chamber 1 constituting the apparatus for producing carbon nanotubes according to the present embodiment.

The gas circulation passage 6 includes a pipe portion 7 and a carbon nanotube collecting portion 8 having a diameter larger than that of the pipe portion 7.
And a gas circulation drive unit 10 having a fan 9 for circulating gas, and a carbon nanotube collection unit 8
Is provided with a filter 11.

The apparatus for manufacturing carbon nanotubes according to the present embodiment configured as described above generates carbon nanotubes as follows.

When a current is supplied from the DC power supply 4, an arc discharge 5 is generated between the pair of carbon rod electrodes 2 and 3.

As a result, carbon nanotubes are generated from the carbon rod electrode 2 acting as a positive electrode.

A part of the product containing the generated carbon nanotubes is discharged upward from the part where the arc discharge 5 is generated, and adheres to the wall surface of the reaction chamber 1. It is released in the form of a spider web or floc.

According to the study of the present inventor, the product containing carbon nanotubes emitted from the part where the arc discharge 5 is generated upwards in a web-like or cotton-like manner is the most carbon nanotubes. It has been found that the purity is high.

Therefore, in this embodiment, the fan 9
As a result, a product containing carbon nanotubes emitted in a web-like or flocculent shape from the portion where the arc discharge 5 was generated is guided upward into the gas circulation passage 6, and the carbon nanotube collecting portion 8 is formed. It is configured to be collected by a filter 11 provided in the apparatus.

That is, a product containing carbon nanotubes of high purity, which is emitted in a web-like or cotton-like shape from the portion where the arc discharge 5 is generated upward, is discharged by the fan 9 into the gas circulation passage 6. Is introduced into the pipe section 7 of the gas circulation passage 6 together with the inert gas circulated through the pipe.

The product containing the carbon nanotubes entrained by the inert gas passes through the pipe section 7 and passes through the pipe section 7.
The liquid is guided to the carbon nanotube collection unit 8 having a larger diameter than that, and is collected by the filter 11 provided in the carbon nanotube collection unit 8.

When the carbon rod electrode 2 acting as a positive electrode is consumed, the DC power supply 4 and the motor are turned off, and the fan 9 is turned off.
Is stopped, and the product containing the carbon nanotubes collected by the filter 11 provided in the carbon nanotube collecting section 8 of the gas circulation passage 6 is collected.

The product containing the carbon nanotubes, which is not collected by the fork-shaped collecting member 7 and adheres to the inner wall surface of the reaction chamber 1, is scraped off by the scraper.

According to the present embodiment, the product containing the carbon nanotubes having the highest purity of the carbon nanotubes discharged in a spider web or cotton shape from the portion where the arc discharge 5 is generated is directed upward. Since it is configured to be led to the carbon nanotube collecting portion 8 in the gas circulation passage 6 by being accompanied by the inert gas and to be collected by the filter 11 provided in the carbon nanotube collecting portion 8, the efficiency is improved. The product with the highest purity of the carbon nanotube can be collected well, and therefore, it is possible to produce the carbon nanotube in a large amount, easily and with a high yield.

Furthermore, according to the present embodiment, since the inert gas is circulated in the gas circulation passage 6 and the reaction chamber 1, the inert gas is supplied into the reaction chamber 1. It is not necessary to continue, and it is possible to greatly reduce the consumption of the inert gas, and the power for continuously supplying the inert gas becomes unnecessary. , It can be produced in large quantities, easily and with high yield.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the invention described in the claims, and these are also included in the scope of the present invention. It goes without saying that it is a thing.

For example, in the embodiment shown in FIG. 1, a product containing carbon nanotubes that are emitted in a web-like or cotton-like shape upward from the portion where the arc discharge 5 is generated, Although the gas is led into the gas circulation passage 6 by the fan 9 together with the inert gas, other gas circulation means such as a pump may be used instead of the fan 9.

In the above embodiment, the carbon rod electrode 2 acting as a positive electrode and the carbon rod electrode 3 acting as a negative electrode are arranged such that their longitudinal axes are located substantially in a horizontal plane. Carbon rod electrode 2 acting as positive electrode
And the carbon rod electrode 3 acting as a negative electrode may be arranged in a substantially vertical plane.

Further, in the above embodiment, an example of producing carbon nanotubes is described, but the present invention is not limited to carbon nanotubes, and can be widely used for producing fullerenes containing carbon nanotubes.

In the above embodiment, the DC power supply 4 is used as a power supply for applying a voltage between the pair of carbon rod electrodes 2 and 3. A voltage can be applied between the electrodes 2 and 3.

Further, in the above embodiment, the carbon rod electrode 2 acting as a positive electrode uses a carbon rod containing Co and Ni as a catalyst when producing carbon nanotubes. Is not limited to Co and Ni, but Sc, V, Cr, M
n, Fe, Cu, Y, Zr, Nb, Mo, Pd, Ta,
W, Au, Th, U, La, Ce, Pr, Nd, Gd,
Tb, Dy, Ho, Er, Tm, Lu or the like can be contained as a catalyst in the carbon rod constituting the carbon rod electrode 2 acting as a positive electrode.

[0059]

According to the present invention, it is possible to provide a method and an apparatus for producing fullerenes, in particular, carbon nanotubes which can be produced in a large amount, easily and with high yield. Become.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a carbon nanotube manufacturing apparatus according to a preferred embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reaction chamber 2 Carbon rod electrode 3 Carbon rod electrode 4 DC power supply 5 Arc discharge 6 Gas circulation path 7 Pipe part 8 Carbon nanotube collection part 9 Fan 10 Gas circulation drive part 11 Filter

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tomichi Watanabe 6-7-35 Kita Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Yoshihiro Nakamura 6-7-1 Kita Shinagawa, Shinagawa-ku, Tokyo No. 35 Inside Sony Corporation (72) Atsushi Yamada, Inventor 6-7-35 Kita Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Seiji Shiroishi 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Ryuichiro Maruyama 6-7-35 Kita Shinagawa, Shinagawa-ku, Tokyo Sonny Corporation (72) Inventor Takashi Kajiura 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Co., Ltd. F-term (reference) 4G046 CA00 CC02 CC06 CC08 CC09

Claims (14)

[Claims] An arc discharge is generated between a pair of carbon rod electrodes in a reaction chamber maintained in a reduced-pressure atmosphere of an inert gas, and a product containing the generated fullerenes is transferred to the inert gas. A method for producing fullerenes, the method comprising: introducing the gas into a gas circulation passage connected to the reaction chamber together with the gas; and collecting the gas by a filter provided in the gas circulation passage. 2. An arc discharge is generated between a pair of carbon rod electrodes, and a product including fullerenes formed in a spider web shape is connected to the reaction chamber with the inert gas. The method for producing fullerenes according to claim 1, wherein the fullerenes are guided to a gas circulation path that has been collected and collected by a filter provided in the gas circulation path. 3. The method for producing fullerenes according to claim 1, wherein the product containing fullerenes contains carbon nanotubes. 4. The product according to claim 1, wherein a product including the fullerenes is guided to the circulation path together with the inert gas by a fan.
The method for producing fullerenes according to the above item. 5. The method according to claim 1, wherein a product containing the fullerenes is led to the circulation path together with the inert gas by a pump.
The method for producing fullerenes according to the above item. 6. The method for producing fullerenes according to claim 1, wherein a carbon rod electrode serving as a positive electrode of the pair of carbon rod electrodes contains a catalyst metal. 7. The catalyst metal is Co, Ni, Sc,
V, Cr, Mn, Fe, Cu, Y, Zr, Nb, Mo,
Pd, Ta, W, Au, Th, U, La, Ce, Pr,
Nd, Gd, Tb, Dy, Ho, Er, Tm and Lu
The method for producing fullerenes according to claim 6, comprising one or more metals selected from the group consisting of: 8. A reaction chamber maintained in a reduced-pressure atmosphere of an inert gas, a pair of carbon rod electrodes provided in the reaction chamber, a gas circulation passage connected to the reaction chamber, An apparatus for producing fullerenes, comprising: a gas circulating unit that circulates a suitable gas through the reaction chamber and the gas circulation passage; and a filter in the circulation passage. 9. The apparatus for producing fullerenes according to claim 8, wherein said gas circulation means is constituted by a fan. 10. The apparatus for producing fullerenes according to claim 8, wherein the gas circulation means is constituted by a pump. 11. The fullerenes according to claim 8, wherein the pair of carbon rod electrodes are arranged in a substantially horizontal plane such that respective ends thereof face each other. Manufacturing equipment. 12. The fullerene according to claim 8, wherein the pair of carbon rod electrodes are arranged in a substantially vertical plane such that respective ends thereof face each other. Kind of manufacturing equipment. 13. The apparatus for producing fullerenes according to claim 8, wherein, among the pair of carbon rod electrodes, a carbon rod electrode serving as a positive electrode contains a catalyst metal. 14. The catalyst metal is Co, Ni, Sc,
V, Cr, Mn, Fe, Cu, Y, Zr, Nb, Mo,
Pd, Ta, W, Au, Th, U, La, Ce, Pr,
Nd, Gd, Tb, Dy, Ho, Er, Tm and Lu
14. The apparatus for producing fullerenes according to claim 13, wherein the apparatus comprises one or more metals selected from the group consisting of: