WO2004099072A1 - Production method and device for single layer carbon nanotube - Google Patents

Production method and device for single layer carbon nanotube Download PDF

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Publication number
WO2004099072A1
WO2004099072A1 PCT/JP2004/002491 JP2004002491W WO2004099072A1 WO 2004099072 A1 WO2004099072 A1 WO 2004099072A1 JP 2004002491 W JP2004002491 W JP 2004002491W WO 2004099072 A1 WO2004099072 A1 WO 2004099072A1
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reaction vessel
net
walled carbon
carbon nanotubes
arc discharge
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PCT/JP2004/002491
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French (fr)
Japanese (ja)
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Yoshinori Ando
Masato Okochi
Xinluo Zhao
Sakae Inoue
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Japan Science And Technology Agency
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/15—Nano-sized carbon materials
    • C01B32/158—Carbon nanotubes
    • C01B32/16—Preparation
    • C01B32/162—Preparation characterised by catalysts
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2202/00—Structure or properties of carbon nanotubes
    • C01B2202/02—Single-walled nanotubes

Definitions

  • the present invention provides a method and a device for producing single-walled carbon nanotubes which are expected to be developed as functional materials such as electronic materials, hydrogen storage materials, and nanostructured materials, and purifying the carbon nanotubes in situ.
  • Carbon nanotubes are attracting attention as high-performance materials because their electrical properties change semiconductingly or metallically depending on the crystallographic structure and diameter.
  • the carbon nanotubes are divided into multi-walled carbon nanotubes (MWNTs) in which two or more layers of graphene sheet are stacked at equal intervals, and single-walled carbon nanotubes (SWNTs) with only one layer.
  • MWNTs multi-walled carbon nanotubes
  • SWNTs single-walled carbon nanotubes
  • Single-walled carbon nanotubes are expected to have a quantum effect derived from a smaller diameter than multi-walled carbon nanotubes, and are of interest for physical properties.
  • Arc discharge, laser evaporation, CVD, etc. are used for the production of carbon nanotubes.
  • the CVD method is suitable for mass production, and the arc discharge is suitable for improving crystallinity.
  • a graphite rod mixed with a metal catalyst is used as the anode, and the graphite rod is evaporated by arc heat.
  • the evaporated graphite is generated as a net-like soot that is wrapped in a spider web around the electrodes and the entire interior of the container. This net-like soot contains single-walled carbon nanotubes.
  • the present inventors investigated and examined various conditions for producing a large amount of net-like soot containing single-walled carbon nanotubes, and arranged the anode and the carbon rod cathode including the Ni-Y catalyst at an acute angle of 30 degrees. Was reported to be effective ("Materials", Vol. 50, No. 7, pp. 357-360).
  • the proportion of single-walled carbon nanotubes in the deposited net soot is not necessarily high Therefore, it is necessary to refine the net soot to increase the purity of the single-walled carbon nanotube.
  • purification of the single-walled carbon nanotubes is not easy due to insufficient mechanical and chemical strength. Insufficient mechanical and chemical strength is considered to be due to poor crystallinity of single-walled carbon nanotubes synthesized using Ni-Y catalyst.
  • the catalyst contains S, so the single-walled carbon nanotube has low mechanical and chemical strength and is easy to purify.
  • the present invention overcomes problems due to low mechanical strength by purifying single-walled carbon nanotubes generated by arc discharge in the same reaction vessel without moving them to another location, and achieves high purity.
  • the purpose is to produce single-walled carbon nanotubes with high productivity.
  • At least two electrodes containing Fe catalyst are opposed to at least two graphite rods on the anode side in a tubular reaction vessel in a direction orthogonal to the tube axis, and H 2 , X
  • An arc discharge is generated between the electrodes while feeding the mixed gas of (inert gas), and at least the carbon vapor evaporated from the anode is placed on the flow of the mixed gas.
  • a reaction vessel wall are deposited as a net-like single-walled carbon nanotube.
  • the arc discharge is stopped, and the atmosphere gas in the reaction vessel is switched from a mixed gas of H 2 and X to a mixed gas of O 2 and X.
  • the inert gas X a rare gas such as He, Ne, Ar, Kr, or Xe or N 2 can be used.
  • the rare gases the heavier ones produce better results, and the same net-like deposits of single-walled carbon nanotubes are produced when N2 is used.
  • Ar a representative of the inert gas X will be described.
  • the apparatus used in this method has a tubular reaction vessel having a base end connected to a pre-chamber and an exhaust pipe open at the tip, and extending in a horizontal direction, and is opposed to the reaction vessel in a direction perpendicular to the tube axis.
  • At least the anode side is provided with a pair of Daraphite electrodes made of Fe catalyst-containing carbon, a discharge power source to which the graphite electrode is connected, and a heating mechanism arranged around the reaction vessel.
  • the pre-chamber has a gas supply pipe that opens the H 2 , Ar mixed gas during the arc discharge and the 02, Ar mixed gas to the exhaust pipe with the heating mechanism turned on after the arc discharge. I have.
  • the net-like sediment from which the impurity carbon has been removed by thermal oxidation is collected by a collecting device arranged on the exhaust pipe side in the reaction vessel.
  • a collecting device arranged on the exhaust pipe side in the reaction vessel.
  • both are made from Fe catalyst-containing carbon
  • the pair of graphite electrodes described above is used.
  • Fig. 1 is a schematic plan view of a single-walled carbon nanotube manufacturing apparatus according to the present invention. SEM photo showing net deposits
  • Figure 4 shows an SEM image of a net-like deposit of single-walled carbon nanotubes treated with hydrochloric acid.
  • Fig. 5 is a TEM photograph showing a net-like deposit of single-walled carbon nanotubes from which Fe fine particles have disappeared after hydrochloric acid treatment.
  • Fig. 6 is a Raraf spectrum showing the Raman spectrum of the obtained single-walled carbon nanotube.
  • a reactor which deposits single-walled carbon nanotubes by evaporating carbon from graphite electrodes by arc discharge.
  • Either direct current arc discharge or alternating current arc discharge can be used.
  • a cylindrical reaction vessel 10 such as a quartz tube is connected to a pre-chamber 11.
  • FIG. 1 One side of the pre-chamber 11 is connected to a vacuum pump 12, and a gas supply pipe 13 for feeding a mixed gas of H 2 and Ar is opened.
  • the gas supply pipe 13 incorporates a pressure control device 19 for adjusting the atmospheric pressure of the reaction vessel 10.
  • a vacuum valve 12a is provided in a pipeline from the pre-champer 11 to the vacuum pump 12.
  • Reaction vessel 10 extends horizontally from pre-chamber 11 to improve operability Preferably.
  • a heating mechanism 14 such as a resistance heater or a radiant heater for heating the net-like deposit of single-walled carbon nanotubes is arranged around the reaction vessel 10, and an exhaust pipe 15 is opened on the opposite side of the prechamber 11. I have.
  • Exhaust pipe 15 is an exhaust pump
  • the flow rate of the mixed gas of H2 and Ar flowing through the exhaust pipe 15 and the flow rate of the mixed gas in the reaction vessel 10 are adjusted by a flow control valve 17 provided on the way.
  • a thermocouple 18 By inserting a thermocouple 18 into the exhaust pipe 15, the ambient temperature of the reaction vessel 10 can be measured.
  • two graphite electrodes 20R and 20L connected to an AC power supply 21 by lead wires 22R and 22L are arranged opposite to each other in a direction orthogonal to the tube axis.
  • the graphite electrodes 20R and 20L can be moved in the reaction vessel 10 in the direction perpendicular to the tube axis by the feeder 23.
  • Graphite electrodes 20R and 20L are prepared by blending carbon with Fe catalyst and molding.
  • the Fe catalyst a fine-particle Fe simple catalyst having a particle size of ⁇ or less, which is produced from an oxide or carbide of Fe, is preferable from the viewpoint of improving the mechanical and chemical strength and the yield of the single-walled carbon nanotube.
  • the Fe fine particles contained in the graphite electrodes 20R and 20L become ultrafine particles of 10 nm or less when evaporated by arc discharge.
  • the vacuum degree in the vacuum pump 12: 13 ⁇ : 1.3X was evacuated to 10- 3 Pa or so, more to feed the mixed gas from the gas supply pipe 13 H2, Ar, 1.3 ⁇
  • the atmosphere pressure is maintained at about 6.7 ⁇ 10 4 Pa. After the atmosphere is adjusted, if an AC voltage of 20 to 30 V is applied between the graphite electrodes 20R and 20L with the heating mechanism 14 turned off, an AC arc discharge A is generated, and carbon evaporates from the graphite electrodes 20R and 20L.
  • the two graphite electrodes 20R and 20L are consumed under the same conditions.
  • the generated carbon vapor is sent to the exhaust pipe 15 side on the mixed gas flow F, and is deposited as a net-like deposit in a space connecting the graphite electrodes 20R and 20L and the inner wall of the reaction vessel 10.
  • the graphite electrodes 20R, 20L are retracted along the tube axis direction D (leftward in FIG. 1) as the deposition progresses, a net-like deposit with a very long length in a predetermined area extending in the tube axis direction D is formed in the reaction vessel 10. Accumulate inside.
  • the arc discharge is terminated and the reaction vessel 10 Vacuum suction is performed by the exhaust pump 16 and the gas fed into the reaction vessel 10 from the gas supply pipe 13 is switched from a mixed gas of H 2 and Ar to a mixed gas of O 2 and Ar.
  • the heating mechanism 14 is turned on, and a mixed gas of O 2 and Ar is sent at a flow rate of 4.0 to 6.0 ⁇ 10 ° CCM to supply oxygen to the reaction vessel 10. maintaining the partial pressure 2.0 ⁇ 4.0X 10 4 Pa, heating the net-like deposits 380 ⁇ 440 ° C while continuing to feed the gas mixture of 0 2, Ar.
  • the net-like sediment from which the impurity carbon has been removed is collected from the exhaust pipe 15 side of the reaction vessel 10 by a collection device 25 disposed inside the reaction vessel 10 slightly.
  • the trapping device 25 has a built-in cooling mechanism that circulates cooling water W to cool the net-like sediment heated to remove impurity carbon and improve trapping efficiency. After collecting the net-like sediment, the reaction vessel 10 is opened, and the collector 25 is taken out of the reaction vessel 10, whereby the single-walled carbon nanotube net-like sediment is collected.
  • Example Fe particles with a particle size of ⁇ or less were used as catalysts, and 1.0% by weight of Fe particles were mixed with graphite, and heated and pressed to prepare graphite electrode 20R, 20L having a diameter of 6 mm and a length of 20 mm.
  • the distance between the tips of the graphite electrodes 20R and 20L was set to 1.5 mm, and the graphite electrodes 20R and 20L were set in a quartz reaction vessel 10 having an inner diameter of 65 mm.
  • Net-like deposit 0 2 has been reduced to llmg in heat treatment in a mixed gas atmosphere of Ar, carbon nanoparticles, impurities carbon such as amorphous carbon is significantly removed contained in the net-like deposits was. Removal of the impurity carbon was due to the low-contrast amorpha bubbles observed in the net-like sediment before the heat treatment (SEM photograph: Fig. 2) and the net-like sediment after the heat treatment (SEM photograph: Fig. 3). It is also confirmed by the disappearance. The heat-treated net-like sediment was collected by a collector 25 and observed with a scanning electron microscope. As a result, it was confirmed that single-walled carbon nanotube bundles had been formed (Fig. 3). In addition, Fe fine particles mixed in the net-like sediment were converted to iron oxide by heat treatment, bonded together and increased in particle size, and were observed as particles with high contrast.
  • the change in the intensity of the D band and G band means that the purification removed amorphous carbon and the abundance of single-walled carbon nanotubes increased significantly.
  • peaks were detected in the radial breathing mode corresponding to the very fine diameter, although there were slight differences in distribution before and after purification.
  • the resulting single-walled carbon nanotubes had high crystallinity, high electrical conductivity, and excellent mechanical-chemical strength.
  • a string taken out of the net-like single-walled carbon nanotube was subjected to a tensile test, a string having a cross-sectional area of about 0.1 mm 2 withstood a load exceeding 100 g.
  • net-like deposits of single-walled carbon nanotubes generated by AC arc discharge are directly heat-treated in a mixed gas atmosphere of 02 and Ar.
  • carbon impurities such as carbon nanoparticles and amorphous carbon contained in the net-like sediment are gasified and removed, and single-wall carbon nanotubes with high purity can be obtained.
  • Ar SWNTs fabrication reactor was switched to a mixed gas of 0 2, Ar from the gas mixture, from a mechanical 'that chemical strength is low The purification difficulty is overcome, and high-purity single-walled carbon nanotubes are produced with high productivity.

Abstract

AC arc discharge A is generated between graphite electrodes (20R, 20L) oppositely provided in a direction perpendicular to the pipe axis in a reaction container (10) kept in an H2-Ar mixture gas atmosphere to produce net-like deposit of a single-layer carbon nanotube in a space formed by connecting the graphite electrodes (20R, 20L) with the inner wall of the reaction container (10). Next, when an atmosphere in the reaction container (10) is switched to an O2-Ar mixture gas and the interior of the reaction container (10) is heated by a heating mechanism (14), carbon impurities such as carbon nano-particles and amorphous carbon contained in the net-like deposit are gasified and removed from the net-like deposit. Accordingly, a single-layer carbon nanotube can be produced and refined using the same reaction container (10) to produce a high-purity, single-layer nanotube easily.

Description

単層力、 ュ、 -ブの製造方法及び装置 技術分野 Method and apparatus for producing single-layer force
本発明は、 電子材料， 水素吸蔵材料， ナノ構造材料等の機能性材料としての展 開が期待される単層カーボンナノチューブを作製し、 その場精製する方法及び装 明  The present invention provides a method and a device for producing single-walled carbon nanotubes which are expected to be developed as functional materials such as electronic materials, hydrogen storage materials, and nanostructured materials, and purifying the carbon nanotubes in situ.
置に関する。 About the installation.
田  Rice field
背景技術 Background art
力一ボンナノチューブは、 結晶学的構造及び直径に応じて電気的特性が半導体 的又は金属的に変わることから高機能材料として注目されている。 力一ボンナノ チューブには、 筒状に巻かれたグラフエンシートが等間隔で 2層以上重なった多 層カーボンナノチューブ （MWNTs) と、 1層だけの単層カーボンナノチューブ (SWNTs) がある。 単層カーボンナノチューブは、 多層カーボンナノチューブ に比較して小さな直径に由来する量子効果が期待され、 物性的な興味がもたれて いる。  Carbon nanotubes are attracting attention as high-performance materials because their electrical properties change semiconductingly or metallically depending on the crystallographic structure and diameter. The carbon nanotubes are divided into multi-walled carbon nanotubes (MWNTs) in which two or more layers of graphene sheet are stacked at equal intervals, and single-walled carbon nanotubes (SWNTs) with only one layer. Single-walled carbon nanotubes are expected to have a quantum effect derived from a smaller diameter than multi-walled carbon nanotubes, and are of interest for physical properties.
力一ボンナノチューブの作製にはアーク放電， レーザ蒸発法， CVD法等があ り、 量産化には CVD法， 結晶性向上にはアーク放電が適している。 直流アーク 放電で単層カーボンナノチューブを作製する場合、 金属触媒を混合したグラファ イト棒を陽極に用い、 アーク熱でグラフアイト棒を蒸発させる。 蒸発したグラフ アイ卜は、 電極の周りから容器の内部全体にわたって蜘蛛の巣状に張り巡らされ たネット状煤として生成される。 このネット状煤に単層カーボンナノチューブが 含まれている。  Arc discharge, laser evaporation, CVD, etc. are used for the production of carbon nanotubes. The CVD method is suitable for mass production, and the arc discharge is suitable for improving crystallinity. When producing single-walled carbon nanotubes by DC arc discharge, a graphite rod mixed with a metal catalyst is used as the anode, and the graphite rod is evaporated by arc heat. The evaporated graphite is generated as a net-like soot that is wrapped in a spider web around the electrodes and the entire interior of the container. This net-like soot contains single-walled carbon nanotubes.
本発明者等は、 単層カーボンナノチューブを含むネット状煤が大量にできる作 製条件を種々調査，検討し、 N i一 Y触媒を含む陽極及び炭素棒陰極を 30度の 鋭角で配置させることが有効であることを報告した （「材料」 第 50巻第 7号第 357〜360頁）。  The present inventors investigated and examined various conditions for producing a large amount of net-like soot containing single-walled carbon nanotubes, and arranged the anode and the carbon rod cathode including the Ni-Y catalyst at an acute angle of 30 degrees. Was reported to be effective ("Materials", Vol. 50, No. 7, pp. 357-360).
堆積したネット状煤に含まれる単層カーボンナノチューブの割合が必ずしも高 くないので、 ネット状煤を精製して単層カーボンナノチューブの純度を上げる必 要がある。 しかし、 単層カーボンナノチューブ自体の機械的'化学的強度が十分 でないため精製が容易でない。 不十分な機械的 ·化学的強度は、 Ni- Y触媒を用 いて合成された単層カーボンナノチューブが結晶性に劣ることに原因があるもの と考えられる。 アーク放電法による単層カーボンナノチューブの作製に S添加 Fe系金属触媒を使用した場合でも、 触媒が Sを含んでいるため単層力一ポンナ ノチューブの機械的 ·化学的強度が低く精製が容易でない。 The proportion of single-walled carbon nanotubes in the deposited net soot is not necessarily high Therefore, it is necessary to refine the net soot to increase the purity of the single-walled carbon nanotube. However, purification of the single-walled carbon nanotubes is not easy due to insufficient mechanical and chemical strength. Insufficient mechanical and chemical strength is considered to be due to poor crystallinity of single-walled carbon nanotubes synthesized using Ni-Y catalyst. Even when an S-added Fe-based metal catalyst is used for the production of single-walled carbon nanotubes by the arc discharge method, the catalyst contains S, so the single-walled carbon nanotube has low mechanical and chemical strength and is easy to purify. Not.
単層カーボンナノチューブの機械的 ·化学的強度に触媒が与える影響を種々調 査 '検討した結果、 触媒として Fe単体が有効であることを見出した。 すなわち、 H2， Arの混合ガス雰囲気中で Fe単体 （触媒） をグラフアイト棒に配合した陽 極と陰極の間でアーク放電させると、 陽極から蒸発した力一ボンが陰極と真空チ ャンバ内壁を結ぶ空間に単層カーボンナノチューブを含むネット状析出物として 堆積する （先願 '特願 2002— 080729号）。  As a result of various investigations on the effect of the catalyst on the mechanical and chemical strength of single-walled carbon nanotubes, we found that Fe alone was effective as a catalyst. In other words, when an arc discharge is caused between the cathode and the cathode in which simple Fe (catalyst) is blended in a graphite rod in a mixed gas atmosphere of H2 and Ar, the vapor evaporated from the anode causes the cathode and the inner wall of the vacuum chamber to form It deposits as a net-like precipitate containing single-walled carbon nanotubes in the connecting space (prior application: Japanese Patent Application No. 2002-080729).
アーク放電雰囲気に H2， Arの混合ガスを使用すると、 ネット状堆積物へのァ モルファスカ一ボンやカーボンナノ粒子の混入が軽減され、 単層カーボンナノチ ユーブの割合が高くなる。 Fe単体触媒の使用により、 単層カーボンナノチュー ブの結晶性， 機械的'化学的強度が向上する。 しかし、 依然としてアモルファス 力一ボン， カーボンナノ粒子， Fe粒子 （触媒） が混入していることに変わりな く、 後続する工程で単層カーボンナノチューブの精製が必要になる。 発明の開示  When a mixed gas of H2 and Ar is used in the arc discharge atmosphere, the mixing of amorphous carbon and carbon nanoparticles into net-like sediments is reduced, and the ratio of single-walled carbon nanotubes is increased. The use of a simple Fe catalyst improves the crystallinity, mechanical and chemical strength of single-walled carbon nanotubes. However, there is still the fact that amorphous carbon, carbon nanoparticles, and Fe particles (catalyst) are still mixed, and it is necessary to purify single-walled carbon nanotubes in the subsequent steps. Disclosure of the invention
本発明は、 アーク放電によって生成した単層カーボンナノチューブを別の場所 に移動させることなく同じ反応容器内で精製することにより、 低い機械的'化学 的強度に起因する問題を克服し、 純度の高い単層カーボンナノチューブを高生産 性で製造することを目的とする。  The present invention overcomes problems due to low mechanical strength by purifying single-walled carbon nanotubes generated by arc discharge in the same reaction vessel without moving them to another location, and achieves high purity. The purpose is to produce single-walled carbon nanotubes with high productivity.
本発明に従った製造方法では、 少なくとも陽極側のグラフアイト棒に Fe触媒 を配合した二本の電極を筒状反応容器の内部で管軸直交方向に対向させ、 反応容 器に H2， X (不活性ガス） の混合ガスを送り込みながら電極間にアーク放電を 発生させ、 少なくとも陽極から蒸発した力一ボンを混合ガスの流れに乗せて電極 と反応容器壁との間にネット状の単層力一ボンナノチューブとして堆積させる。 ネット状堆積物の堆積に応じグラフアイト電極をプレチャンパ側に相対移動さ せると、 反応容器の管軸方向に沿った所定長さ域に極長のネット状堆積物が生成 する。 In the production method according to the present invention, at least two electrodes containing Fe catalyst are opposed to at least two graphite rods on the anode side in a tubular reaction vessel in a direction orthogonal to the tube axis, and H 2 , X An arc discharge is generated between the electrodes while feeding the mixed gas of (inert gas), and at least the carbon vapor evaporated from the anode is placed on the flow of the mixed gas. And a reaction vessel wall are deposited as a net-like single-walled carbon nanotube. When the graphite electrode is relatively moved to the pre-champer side in accordance with the deposition of the net-like deposit, an extremely long net-like deposit is generated in a predetermined length region along the tube axis direction of the reaction vessel.
なかでも、 グラフアイト棒に Fe触媒を配合した 2本の電極間に交流アーク放 電を発生させて両極からカーボンを蒸発させると、 単層カーボンナノチューブを 含まない陰極堆積物がなくなり、 直流アーク放電に比較して蒸発炭素量に対する 単層カーボンナノチューブの生成割合が高くなる。  Above all, when AC arc discharge is generated between two electrodes containing Fe catalyst on graphite rods and carbon is evaporated from both electrodes, cathode deposits containing no single-walled carbon nanotubes disappear, and DC arc discharge The ratio of single-walled carbon nanotubes to the amount of evaporated carbon is higher than that of carbon nanotubes.
所定長さ域にネット状堆積物を生成させた後、 アーク放電を中止し、 反応容器 の雰囲気ガスを H2, Xの混合ガスから 02， Xの混合ガスに切り替える。 そして、After the net-like sediment is generated in the specified length area, the arc discharge is stopped, and the atmosphere gas in the reaction vessel is switched from a mixed gas of H 2 and X to a mixed gas of O 2 and X. And
02, Xの混合ガスを送り込みながら反応容器全体を加熱することにより、 単層 カーボンナノチューブのネット状堆積物からカーボンナノ粒子， アモルファス力 一ボン等の不純物炭素がガス化して除去される。 併せて、 Fe粒子 （触媒） の表 面が酸化される。 不純物炭素が除去された単層カーボンナノチューブのネット状 堆積物を反応容器から取り出し、 塩酸処理によって酸化された Fe触媒を除去す ると、 純度の高い単層カーボンナノチューブが得られる。 0 2, by heating the entire reaction vessel while feeding the mixed gas of X, single-walled carbon carbon nanoparticles from the net-like deposits nanotubes, impurities carbon such as amorphous force one carbon is removed by gasification. At the same time, the surface of the Fe particles (catalyst) is oxidized. When the net-like deposit of single-walled carbon nanotubes from which impurity carbon has been removed is removed from the reaction vessel, and the Fe catalyst oxidized by the hydrochloric acid treatment is removed, high-purity single-walled carbon nanotubes can be obtained.
不活性ガス Xとしては、 He， Ne， Ar， Kr, Xe等の希ガスや N2を使用でき る。 希ガスの中でも重い希ガスほど好結果が得られ、 N2を用いた場合でも同様 な単層カーボンナノチューブのネット状堆積物が生成する。 以下の説明では、 不 活性ガス Xの代表として Arを用いた例で説明する。 As the inert gas X, a rare gas such as He, Ne, Ar, Kr, or Xe or N 2 can be used. Among the rare gases, the heavier ones produce better results, and the same net-like deposits of single-walled carbon nanotubes are produced when N2 is used. In the following description, an example using Ar as a representative of the inert gas X will be described.
この方法に使用する装置は、 基端がプレチャンバに接続され、 先端に排気管が 開口している水平方向に延びた筒状反応容器と、 該反応容器内で管軸直交方向に 対向させた少なくとも陽極側が Fe触媒配合カーボンから作製された一対のダラ ファイト電極と、 該グラフアイ卜電極が接続された放電電源と、 反応容器の周囲 に配置された加熱機構とを備えている。 プレチャンバには、 アーク放電中に H2， Arの混合ガスを、 アーク放電終了後に加熱機構をオンした状態で 02， Arの混 合ガスを排気管に向けて流すガス供給管が開口している。 加熱酸化で不純物炭素 が除去されたネット状堆積物は、 反応容器内の排気管側に配置されている捕集装 置で捕集される。 交流電源を使用する場合、 共に Fe触媒配合カーボンから作製 された一対のグラフアイト電極が使用される。 図面の簡単な説明 The apparatus used in this method has a tubular reaction vessel having a base end connected to a pre-chamber and an exhaust pipe open at the tip, and extending in a horizontal direction, and is opposed to the reaction vessel in a direction perpendicular to the tube axis. At least the anode side is provided with a pair of Daraphite electrodes made of Fe catalyst-containing carbon, a discharge power source to which the graphite electrode is connected, and a heating mechanism arranged around the reaction vessel. The pre-chamber has a gas supply pipe that opens the H 2 , Ar mixed gas during the arc discharge and the 02, Ar mixed gas to the exhaust pipe with the heating mechanism turned on after the arc discharge. I have. The net-like sediment from which the impurity carbon has been removed by thermal oxidation is collected by a collecting device arranged on the exhaust pipe side in the reaction vessel. When using an AC power supply, both are made from Fe catalyst-containing carbon The pair of graphite electrodes described above is used. BRIEF DESCRIPTION OF THE FIGURES
図 1は、 本発明に従った単層カーボンナノチューブ製造装置の概略平面図 図 2は、 作製直後の単層カーボンナノチューブのネット状堆積物を示す SEM 図 3 は、 加熱処理直後の単層カーボンナノチューブのネット状堆積物を示す SEM写真  Fig. 1 is a schematic plan view of a single-walled carbon nanotube manufacturing apparatus according to the present invention. SEM photo showing net deposits
図 4 は、 塩酸処理した単層カーボンナノチューブのネット状堆積物を示す SEM写真  Figure 4 shows an SEM image of a net-like deposit of single-walled carbon nanotubes treated with hydrochloric acid.
図 5は、 塩酸処理後で Fe微粒子が消失した単層カーボンナノチューブのネッ ト状堆積物を示す TEM写真  Fig. 5 is a TEM photograph showing a net-like deposit of single-walled carbon nanotubes from which Fe fine particles have disappeared after hydrochloric acid treatment.
図 6 は、 得られた単層力一ボンナノチューブのラマンスペクトルを示すダラ フ 発明を実施するための最良の形態  Fig. 6 is a Raraf spectrum showing the Raman spectrum of the obtained single-walled carbon nanotube.
本発明では、 アーク放電でグラフアイト電極から炭素を蒸発させ単層カーボン ナノチューブを堆積させる反応装置を使用する。 直流アーク放電， 交流アーク放 電の何れも採用可能であるが、 直流アーク放電による場合、 Fe触媒配合カーボ ンから作製されたグラフアイト電極を陽極に、 Fe触媒を含まないグラフアイト 電極を陰極に使用し、 陽極から炭素を蒸発させる。 その他は交流アーク放電によ る場合と同様であるので、 以下では交流アーク放電による炭素の蒸発， 単層力一 ボンナノチューブの生成を説明する。  In the present invention, a reactor is used which deposits single-walled carbon nanotubes by evaporating carbon from graphite electrodes by arc discharge. Either direct current arc discharge or alternating current arc discharge can be used. Use to evaporate the carbon from the anode. Since the other points are the same as those by the AC arc discharge, the evaporation of carbon and the formation of single-walled carbon nanotubes by the AC arc discharge will be described below.
反応装置は、 石英管等の筒状反応容器 10をプレチャンバ 11 に接続している In the reactor, a cylindrical reaction vessel 10 such as a quartz tube is connected to a pre-chamber 11.
(図 1)。 プレチャンバ 11の一側が真空ポンプ 12に接続され、 H2， Arの混合 ガスを送り込むガス供給管 13が開口している。 ガス供給管 13 には、 反応容器 10 の雰囲気圧を調節する圧力制御装置 19が組み込まれている。 プレチャンパ 11から真空ボンプ 12に至る管路には、 真空バルブ 12aが設けられている。 反応容器 10は、 操作性を向上するためプレチャンバ 11から水平方向に延在 させることが好ましい。 反応容器 10の周囲には単層カーボンナノチューブのネ ッ卜状堆積物を加熱する抵抗加熱器， 輻射加熱器等の加熱機構 14が配置され、 プレチヤンバ 11と反対側に排気管 15が開口している。 排気管 15は排気ポンプ(Figure 1). One side of the pre-chamber 11 is connected to a vacuum pump 12, and a gas supply pipe 13 for feeding a mixed gas of H 2 and Ar is opened. The gas supply pipe 13 incorporates a pressure control device 19 for adjusting the atmospheric pressure of the reaction vessel 10. A vacuum valve 12a is provided in a pipeline from the pre-champer 11 to the vacuum pump 12. Reaction vessel 10 extends horizontally from pre-chamber 11 to improve operability Preferably. A heating mechanism 14 such as a resistance heater or a radiant heater for heating the net-like deposit of single-walled carbon nanotubes is arranged around the reaction vessel 10, and an exhaust pipe 15 is opened on the opposite side of the prechamber 11. I have. Exhaust pipe 15 is an exhaust pump
16に接続されており、 途中に設けた流量調整弁 17で排気管 15を流れる H2， Ar の混合ガスの流量， ひいては反応容器 10内の混合ガス流量が調整される。 排気管 15内に熱電対 18を挿し込んでおくと、 反応容器 10の雰囲気温度を測定 できる。 ， The flow rate of the mixed gas of H2 and Ar flowing through the exhaust pipe 15 and the flow rate of the mixed gas in the reaction vessel 10 are adjusted by a flow control valve 17 provided on the way. By inserting a thermocouple 18 into the exhaust pipe 15, the ambient temperature of the reaction vessel 10 can be measured. ,
反応容器 10内に、 交流電源 21にリード線 22R, 22Lで接続された二本のグ ラフアイト電極 20R， 20Lが管軸直交方向に対向配置されている。 グラフアイ ト電極 20R, 20Lは、 送り装置 23によって反応容器 10内を管軸直交方向に移 動可能になっている。 グラフアイト電極 20R， 20Lはカーボンに Fe触媒を配合 して成形することにより用意される。 Fe触媒としては、 Feの酸化物や炭化物等 から製造された粒径 Ιμιη以下の微粒状 Fe単体触媒が単層カーボンナノチュー ブの機械的 ·化学的強度， 収率を向上させる上で好ましい。 グラフアイト電極 20R， 20Lに含まれている Fe微粒子は、 アーク放電によって蒸発すると 10nm 以下の超微粒子になる。  In the reaction vessel 10, two graphite electrodes 20R and 20L connected to an AC power supply 21 by lead wires 22R and 22L are arranged opposite to each other in a direction orthogonal to the tube axis. The graphite electrodes 20R and 20L can be moved in the reaction vessel 10 in the direction perpendicular to the tube axis by the feeder 23. Graphite electrodes 20R and 20L are prepared by blending carbon with Fe catalyst and molding. As the Fe catalyst, a fine-particle Fe simple catalyst having a particle size of Ιμιη or less, which is produced from an oxide or carbide of Fe, is preferable from the viewpoint of improving the mechanical and chemical strength and the yield of the single-walled carbon nanotube. The Fe fine particles contained in the graphite electrodes 20R and 20L become ultrafine particles of 10 nm or less when evaporated by arc discharge.
反応容器 10内の雰囲気は、 真空ポンプ 12で真空度： 13〜： 1.3X 10— 3Pa程度 まで真空吸引した後、 ガス供給管 13から H2, Arの混合ガスを送り込むことに より、 1.3~6.7X 104Pa程度の雰囲気圧に維持される。 雰囲気調整後、 加熱機構 14がオフの状態でグラフアイト電極 20R, 20L間に 20〜30Vの交流電圧を印加 すると交流アーク放電 Aが発生し、 グラフアイト電極 20R， 20Lから炭素が蒸 発する。 Atmosphere in the reaction vessel 10, the vacuum degree in the vacuum pump 12: 13~: 1.3X was evacuated to 10- 3 Pa or so, more to feed the mixed gas from the gas supply pipe 13 H2, Ar, 1.3 ~ The atmosphere pressure is maintained at about 6.7 × 10 4 Pa. After the atmosphere is adjusted, if an AC voltage of 20 to 30 V is applied between the graphite electrodes 20R and 20L with the heating mechanism 14 turned off, an AC arc discharge A is generated, and carbon evaporates from the graphite electrodes 20R and 20L.
交流アーク放電による炭素蒸発であるため、 二本のグラフアイト電極 20R, 20Lは同じ条件下で消費される。 発生した炭素蒸気は、 混合ガスの流れ F に乗 つて排気管 15側に送られ、 ネット状堆積物としてグラフアイト電極 20R, 20L と反応容器 10の内壁とを結ぶ空間に堆積する。 堆積の進行に応じグラフアイト 電極 20R, 20Lを管軸方向 Dに沿って後退 （図 1では左方向） させると、 管軸 方向 Dに延びる所定域で極長のネット状堆積物が反応容器 10内に溜まる。 所定量のネット状堆積物が生成した後、 アーク放電を終了し、 反応容器 10を 排気ポンプ 16で真空吸引し、 ガス供給管 13から反応容器 10に送り込まれるガ スを H2, Arの混合ガスから 02, Arの混合ガスに切り替える。 反応容器 10内 の酸素分圧が 2.0〜4.0X 104Paに達した段階で加熱機構 14をオンし、 流量 4.0 〜6.0X 10¾CCMで 02, Arの混合ガスを送り込んで反応容器 10の酸素分圧を 2.0~4.0X 104Paに維持し、 引き続き 02， Arの混合ガスを供給しながらネット 状堆積物を 380~440°Cに加熱する。 Since the carbon is evaporated by AC arc discharge, the two graphite electrodes 20R and 20L are consumed under the same conditions. The generated carbon vapor is sent to the exhaust pipe 15 side on the mixed gas flow F, and is deposited as a net-like deposit in a space connecting the graphite electrodes 20R and 20L and the inner wall of the reaction vessel 10. When the graphite electrodes 20R, 20L are retracted along the tube axis direction D (leftward in FIG. 1) as the deposition progresses, a net-like deposit with a very long length in a predetermined area extending in the tube axis direction D is formed in the reaction vessel 10. Accumulate inside. After a predetermined amount of net-like sediment is generated, the arc discharge is terminated and the reaction vessel 10 Vacuum suction is performed by the exhaust pump 16 and the gas fed into the reaction vessel 10 from the gas supply pipe 13 is switched from a mixed gas of H 2 and Ar to a mixed gas of O 2 and Ar. When the partial pressure of oxygen in the reaction vessel 10 reaches 2.0 to 4.0 × 10 4 Pa, the heating mechanism 14 is turned on, and a mixed gas of O 2 and Ar is sent at a flow rate of 4.0 to 6.0 × 10 ° CCM to supply oxygen to the reaction vessel 10. maintaining the partial pressure 2.0 ~ 4.0X 10 4 Pa, heating the net-like deposits 380 ~ 440 ° C while continuing to feed the gas mixture of 0 2, Ar.
02, Arの混合ガス雰囲気中での加熱により、 ネット状堆積物に混入している カーボンナノ粒子， アモルファスカーボン等の不純物は、 CO, CO2等に酸化さ れ、 ガス化してネット状堆積物から除去され、 Fe微粒子 （触媒） が酸化される。 ネット状堆積物は、 混合ガスの流れ Fに乗ってグラフアイト電極 20R, 20Lか ら離れ、 排気管 15 に向けて浮遊する。 反応容器 10内をネット状堆積物が浮遊 流動する時間を 30〜120分に設定するとき、 不純物炭素の酸化除去が十分に進 行する。 0 2, by heating in a mixed gas atmosphere of Ar, carbon nanoparticles mixed in a net-like deposits, impurities such as amorphous carbon, CO, are oxidized to CO2 and the like, net-like deposits gasified , And the fine Fe particles (catalyst) are oxidized. The net-like sediment rides on the mixed gas flow F, separates from the graphite electrodes 20R, 20L, and floats toward the exhaust pipe 15. When the time during which the net-like sediment floats and flows in the reaction vessel 10 is set to 30 to 120 minutes, the oxidative removal of the impurity carbon proceeds sufficiently.
不純物炭素が除去されたネット状堆積物は、 反応容器 10内の排気管 15側か ら反応容器 10に若干入った内部に配置されている捕集装置 25で捕集される。 捕集装置 25は、 不純物炭素除去のために加熱されたネット状堆積物を冷却する と共に、 捕集効率を向上させるため、 冷却水 Wを循環させる冷却機構を内蔵し ている。 ネット状堆積物を捕集した後、 反応容器 10を開放し、 反応容器 10か ら捕集装置 25 を取り出すことにより単層カーボンナノチューブネット状堆積物 が回収される。  The net-like sediment from which the impurity carbon has been removed is collected from the exhaust pipe 15 side of the reaction vessel 10 by a collection device 25 disposed inside the reaction vessel 10 slightly. The trapping device 25 has a built-in cooling mechanism that circulates cooling water W to cool the net-like sediment heated to remove impurity carbon and improve trapping efficiency. After collecting the net-like sediment, the reaction vessel 10 is opened, and the collector 25 is taken out of the reaction vessel 10, whereby the single-walled carbon nanotube net-like sediment is collected.
反応容器 10から取り出されたネット状堆積物に含まれている Fe触媒は、 02， Ar の混合ガス雰囲気中での加熱処理によって酸化されているので、 塩酸処理に よってネット状堆積物から容易に除去される。 その結果、 高純度の単層カーボン ナノチューブが得られる。 この方法は、 長さ 20〜30cm にもわたる長いネット 状に連なった単層カーボンナノチューブの作製を可能にする。 該単層カーボンナ ノチューブをシート状， 糸状等に成形するとき、 機械的強度の高い単層カーボン ナノチューブ材料が提供される。 実施例 粒径 Ιμπι以下の Fe微粒子を触媒に使用し、 グラフアイトに Fe微粒子を 1.0 重量％配合して加熱加圧することにより直径 6mm， 長さ 20mmのグラフアイト 電極 20R， 20L を用意した。 グラフアイト電極 20R， 20L の先端間距離を 1.5mmに設定し、 内径 65mmの石英製反応容器 10内にグラフアイト電極 20R, 20Lをセッ卜した。 Fe catalyst contained in the net-like deposit that is removed from the reaction vessel 10, 0 2, because it is oxidized by heat treatment in a mixed gas atmosphere of Ar, thus facilitating the net-like deposits hydrochloric acid treatment Is removed. As a result, high-purity single-walled carbon nanotubes are obtained. This method makes it possible to produce long net-like single-walled carbon nanotubes ranging in length from 20 to 30 cm. When the single-walled carbon nanotube is formed into a sheet, a thread or the like, a single-walled carbon nanotube material having high mechanical strength is provided. Example Fe particles with a particle size of Ιμπι or less were used as catalysts, and 1.0% by weight of Fe particles were mixed with graphite, and heated and pressed to prepare graphite electrode 20R, 20L having a diameter of 6 mm and a length of 20 mm. The distance between the tips of the graphite electrodes 20R and 20L was set to 1.5 mm, and the graphite electrodes 20R and 20L were set in a quartz reaction vessel 10 having an inner diameter of 65 mm.
反応容器 10 を真空ポンプ 12で真空排気した後、 ガス供給管 13から H2： Ar=2： 3 (体積比） の混合ガスを反応容器 10に送り込み、 反応容器 10の雰囲 気圧を 1.3X 104Paに維持した。 After evacuating the reaction vessel 10 with a vacuum pump 12, a mixed gas of H2: Ar = 2: 3 (volume ratio) is sent from the gas supply pipe 13 to the reaction vessel 10, and the atmospheric pressure of the reaction vessel 10 is reduced to 1.3 × 10 Maintained at 4 Pa.
グラフアイト電極 20R， 20L間に 27Vの交流電圧を印加するとアーク放電が 発生し、 グラフアイト電極 20R, 20Lから炭素が蒸発し始めた。 交流アーク放 電の進行に伴い、 グラフアイト電極 20R, 20Lと反応容器 10の内壁を結ぶ空間 にネット状堆積物が堆積した。 グラフアイト電極 20R, 20Lを 1.3mm/分の速 度でプレチャンバ 11 に向けて移動させながら交流アーク放電を 1分間継続させ たところ、 質量 14mgのネット状堆積物が生成した。  When an AC voltage of 27 V was applied between the graphite electrodes 20R and 20L, an arc discharge occurred, and carbon began to evaporate from the graphite electrodes 20R and 20L. With the progress of the AC arc discharge, net-like deposits were deposited in the space between the graphite electrodes 20R and 20L and the inner wall of the reaction vessel 10. When the arc discharge was continued for 1 minute while moving the graphite electrodes 20R and 20L toward the pre-chamber 11 at a speed of 1.3 mm / min, a net-like deposit having a mass of 14 mg was generated.
グラフアイト電極 20R, 20Lの移動に代え、 グラフアイト電極 20R， 20Lを 固定し、 反応容器 10を管軸方向 Dに移動させた場合でも、 管軸方向 Dに沿つ た所定長さ域にネット状堆積物が反応容器 10内に生成する。  Even when the graphite electrodes 20R, 20L are fixed and the reaction vessel 10 is moved in the tube axis direction D instead of the movement of the graphite electrodes 20R, 20L, a net is formed in a predetermined length region along the tube axis direction D. Deposits are formed in the reaction vessel 10.
次いで、 グラフアイト電極 20R， 20Lへの電力投入を中止し、 反応容器 10を 真空引きした後、 ガス供給管 13から 02： Ar=3： 7 (体積比） の混合ガスを反 応容器 10に送り込み、 反応容器 10の酸素分圧を 3 X 104Paに維持した。 該酸 素分圧が維持される条件下で 02， Arの混合ガスを反応容器 10に送り込みなが ら、 加熱機構 14により反応容器 10の雰囲気温度を上げ、 400°Cに 30分保持し た。 Next, the supply of power to the graphite electrodes 20R and 20L was stopped, and the reaction vessel 10 was evacuated. After that, a mixed gas of 02: Ar = 3: 7 (volume ratio) was supplied from the gas supply pipe 13 to the reaction vessel 10. The oxygen partial pressure of the reaction vessel 10 was maintained at 3 × 10 4 Pa. The atmosphere temperature of the reaction vessel 10 was increased by the heating mechanism 14 while the mixed gas of 02 and Ar was fed to the reaction vessel 10 under the condition that the oxygen partial pressure was maintained, and the temperature was maintained at 400 ° C. for 30 minutes. .
ネット状堆積物は 02， Arの混合ガス雰囲気中での加熱処理で llmgに減量し たが、 ネット状堆積物に含まれていたカーボンナノ粒子， アモルファスカーボン 等の不純物炭素が大幅に除去された。 不純物炭素の除去は、 加熱処理前のネット 状堆積物 (SEM写真：図 2) で観察されていたコントラストの弱いァモルファ スカ一ボンが加熱処理後のネット状堆積物 （SEM写真：図 3) で消失している ことによつても確認される。 加熱処理されたネット状堆積物を捕集装置 25で捕集し、 走査型電子顕微鏡で 観察したところ、 単層カーボンナノチューブのバンドルが形成されていることが 確認された （図 3)。 また、 ネット状堆積物に混入している Fe微粒子は、 加熱処 理によつて酸化鉄になり相互に結合し大粒径化し、 コントラストの強い粒子とし て観察された。 Net-like deposit 0 2 has been reduced to llmg in heat treatment in a mixed gas atmosphere of Ar, carbon nanoparticles, impurities carbon such as amorphous carbon is significantly removed contained in the net-like deposits Was. Removal of the impurity carbon was due to the low-contrast amorpha bubbles observed in the net-like sediment before the heat treatment (SEM photograph: Fig. 2) and the net-like sediment after the heat treatment (SEM photograph: Fig. 3). It is also confirmed by the disappearance. The heat-treated net-like sediment was collected by a collector 25 and observed with a scanning electron microscope. As a result, it was confirmed that single-walled carbon nanotube bundles had been formed (Fig. 3). In addition, Fe fine particles mixed in the net-like sediment were converted to iron oxide by heat treatment, bonded together and increased in particle size, and were observed as particles with high contrast.
加熱処理後のネット状堆積物に塩酸を添加すると、 塩酸が直ちに黄変した。 塩 酸の黄変は酸化鉄がネッ卜状堆積物から塩酸に溶出した結果であり、 単層カーボ ンナノチューブを容易に精製できることを意味する。 塩酸処理後に、 4mgの単 層力一ボンナノチューブが回収された。  When hydrochloric acid was added to the heat-treated net-like sediment, the hydrochloric acid immediately turned yellow. The yellowing of hydrochloric acid is the result of the elution of iron oxide from the net-like sediment into hydrochloric acid, which means that single-walled carbon nanotubes can be easily purified. After the hydrochloric acid treatment, 4 mg of single-walled carbon nanotubes were recovered.
精製された単層カーボンナノチューブには、 Fe微粒子の混入が検出されなか つた （SEM写真：図 4)。 Fe微粒子のない単層カーボンナノチューブのネット 状堆積物は、 透過型電子顕微鏡でも観察された （TEM写真：図 5)。 ラマン測定 の結果 （図 6) では、 精製の前後でもともと弱かった 1340cm-1近傍にある D バンドの強度が更に弱くなり、 1590CHT 1近傍にある Gバンドの強度が強くな つていた。 Gバンドのピークにも、 通常の単層力一ボンナノチューブと同様な スプリツチングが検出された。 No contamination of Fe fine particles was detected in the purified single-walled carbon nanotubes (SEM photograph: Fig. 4). A net-like deposit of single-walled carbon nanotubes without Fe fine particles was also observed with a transmission electron microscope (TEM photograph: Fig. 5). In the results of the Raman measurements (FIG. 6), the intensity of the D band in 1340Cm- 1 near it was originally weak before and after the purification is further weakened, a strong intensity of G-band in 1590CHT 1 near Tsuteita. Splitting similar to that of ordinary single-walled carbon nanotubes was also detected at the G-band peak.
Dパンド， Gバンドの強度変化は、 精製によってアモルファス力一ボンが除 去され、 単層カーボンナノチューブの存在比が著しく上昇したことを意味する。 極微細な直径に対応するラジアルブリージングモードは、 図 6 の挿入図にみら れるように、 精製前後で若干の分布に違いがあるものの何れもピークが検出され た。  The change in the intensity of the D band and G band means that the purification removed amorphous carbon and the abundance of single-walled carbon nanotubes increased significantly. As shown in the inset of Fig. 6, peaks were detected in the radial breathing mode corresponding to the very fine diameter, although there were slight differences in distribution before and after purification.
得られた単層力一ボンナノチューブは、 結晶性， 電気伝導度が高く、 機械的- 化学的強度にも優れていた。 実際、 網状の単層カーボンナノチューブから取り出 した紐を引張試験に供したところ、 断面積 0.1mm2程度の紐でも 100gを超える 荷重に耐えた。 産業上の利用可能性 · The resulting single-walled carbon nanotubes had high crystallinity, high electrical conductivity, and excellent mechanical-chemical strength. Actually, when a string taken out of the net-like single-walled carbon nanotube was subjected to a tensile test, a string having a cross-sectional area of about 0.1 mm 2 withstood a load exceeding 100 g. Industrial Applicability ·
以上に説明したように、 交流アーク放電で生成した単層カーボンナノチューブ のネット状堆積物をそのまま 02, Arの混合ガス雰囲気中で加熱処理することに より、 ネット状堆積物に含まれている力一ボンナノ粒子， アモルファスカーボン 等の不純物炭素がガス化して除去され、 純度の高い単層カーボンナノチューブが 得られる。 雰囲気を H2, Arの混合ガスからから 02, Arの混合ガスに切り替え た単層カーボンナノチューブ作製用反応容器でネット状堆積物を加熱処理できる ため、 機械的'化学的強度が低いことに由来する精製の困難性が克服され、 純度 の高い単層力一ボンナノチューブが高生産性で製造される。 As described above, net-like deposits of single-walled carbon nanotubes generated by AC arc discharge are directly heat-treated in a mixed gas atmosphere of 02 and Ar. Thus, carbon impurities such as carbon nanoparticles and amorphous carbon contained in the net-like sediment are gasified and removed, and single-wall carbon nanotubes with high purity can be obtained. Since the atmosphere can be heated net-like deposits in the H2, Ar SWNTs fabrication reactor was switched to a mixed gas of 0 2, Ar from the gas mixture, from a mechanical 'that chemical strength is low The purification difficulty is overcome, and high-purity single-walled carbon nanotubes are produced with high productivity.

Claims

請求の範囲 少なくとも陽極側のグラフアイト棒に Fe触媒を配合した 2本の電極を筒 状反応容器の内部で管軸直交方向に対向させ、 反応容器に H2， X (ただし、 Xは不活性ガス） の混合ガスを送り込みながら電極間にアーク放電を発生さ せ、 少なくとも陽極から蒸発したカーボンを混合ガスの流れに乗せて電極と 反応容器の内壁との間にネット状の単層カーボンナノチューブとして堆積さ せ、 アーク放電終了後に 02， Xの混合ガスを送り込みながら反応容器全体を 加熱することにより単層カーボンナノチューブのネット状堆積物から不純物 炭素を除去することを特徴とする単層カーボンナノチューブの製造方法。 Claims At least two electrodes containing Fe catalyst at the graphite rod on the anode side are opposed in the direction perpendicular to the tube axis inside the cylindrical reaction vessel, and H2, X (where X is an inert gas) An arc discharge is generated between the electrodes while feeding the mixed gas of (1), and at least carbon evaporated from the anode is carried on the flow of the mixed gas and deposited as net-like single-walled carbon nanotubes between the electrodes and the inner wall of the reaction vessel. The production of single-walled carbon nanotubes is characterized by removing the impurity carbon from the net-like deposits of single-walled carbon nanotubes by heating the whole reaction vessel while feeding a mixed gas of 02 and X after the completion of the arc discharge. Method.
2. Fe触媒を配合したグラフアイト棒から作製された一対の電極間に交流ァー ク放電を発生させる請求項 1記載の製造方法。  2. The production method according to claim 1, wherein an alternating current arc discharge is generated between a pair of electrodes produced from a graphite rod containing a Fe catalyst.
基端がプレチャンバに接続され、 先端に排気管が開口している筒状反応容 器と、 該反応容器内で管軸直交方向に対向させた少なくとも陽極側が Fe触 媒配合カーボンから作製された一対のグラフアイト電極と、 該グラフアイト 電極が接続された放電電源と、 反応容器の周囲に配置された加熱機構と、 ァ ーク放電中に H2, X (ただし、 Xは不活性ガス） の混合ガスを、 アーク放電 終了後に加熱機構をオンした状態で 02， Xの混合ガスを排気管に向けて流す プレチャンパに開口したガス供給管と、 排気管側の反応容器内に配置された 捕集装置を備えていることを特徴とする単層カーボンナノチューブの製造装 A cylindrical reaction vessel having a base end connected to a pre-chamber and an exhaust pipe opened at the tip, and at least the anode side opposed to the pipe axis orthogonal direction in the reaction vessel was made of Fe catalyst-containing carbon. A pair of graphite electrodes, a discharge power source to which the graphite electrodes are connected, a heating mechanism arranged around the reaction vessel, and H 2 , X (where X is an inert gas) during arc discharge With the heating mechanism turned on after the arc discharge, the mixed gas of 0, 2 and X flows toward the exhaust pipe. The gas supply pipe opened to the pre-chamber and the reaction vessel on the exhaust pipe side are placed in the reaction vessel. An apparatus for producing single-walled carbon nanotubes, comprising a trapping device.
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