WO2002024572A1

WO2002024572A1 - Hybrid single-wall carbon nanotube

Info

Publication number: WO2002024572A1
Application number: PCT/JP2001/008194
Authority: WO
Inventors: Sumio Iijima; Shunji Bandow; Kazutomo Suenaga; Kaori Hirahara; Toshiya Okazaki; Hisanori Shinohara
Original assignee: Japan Science And Technology Corporation; Japan As Represented By Director General Of Nagoya University; Nec Corporation
Priority date: 2000-09-20
Filing date: 2001-09-20
Publication date: 2002-03-28
Also published as: JP2002097009A

Abstract

A novel hybrid single-wall carbon nanotube capable of encapsulating various substances in clearances in cylinders and having the possibility of finding its applications in extensive fields such as information telecommunications and chemical industries. The hybrid single-wall carbon nanotube comprises foreign substances encapsulated in clearances in the cylinders of a single-wall carbon nanotube.

Description

Description Hybrid Single-Walled Carbon Nanotube Technical Field

The invention of this application relates to a hybrid single-walled carbon nanotube. More specifically, the invention of this application is a new hybrid single-walled carbon nanotube that has the potential to be used in a wide range of fields such as information and communication and the chemical industry, because various substances can be included in the space inside the cylinder It is about. Background art

Carbon nanotubes are attracting attention as next-generation high-performance materials in a wide range of fields, including the energy field, information and communications, aerospace, biological and medical fields. This carbon nanotube has a so-called single-walled carbon nanotube (SWNT), which has a single layer of graphitic sheet that forms the tube, and a multi-layered carbon, in which a large number of graphitic sheet cylinders are nested. There is a nanotube (MWNT). In research and development to efficiently apply the electron emission function, hydrogen storage function, magnetic function, etc. of these carbon nanotubes, SWNT is mainly used because of its simpler structure and its unique properties. I have. In recent years, there has been debate about creating new chemically or physically modified nanocomposites by processing SWNTs in various ways.

Specifically, the possibility of changing the electrical and mechanical characteristics of SWN T itself to completely different ones was discussed, and the introduction of various atoms, molecules, etc. into the cavity inside the cylinder of SWN T was discussed. Is being promoted. And SWN C ₆ in the space inside the cylinder C ₆ encapsulating the molecule. @ SWNT (the symbol @ generally means inclusion) has already been discovered. In addition, the inventors of the present application have proposed a multi-walled carbon nanotube containing a foreign substance and a method for producing the same (Japanese Patent Application No. 4-314147).

However, at present, no new material based on SWNT and containing various substances in the voids in the cylinder and its manufacturing technology are known.

Therefore, the invention of this application has been made in view of the above circumstances, and can include various substances in the space inside the cylinder, and is used in a wide range of fields such as information and communication and the chemical industry. The goal is to provide new hybrid single-walled carbon nanotubes with potential. Disclosure of the invention

Thus, the invention of this application provides the following inventions to solve the above problems.

That is, first of all, the invention of this application provides a hybrid single-walled carbon nanotube characterized in that a foreign substance is included in a cylindrical space of the single-walled carbon nanotube.

Second, the invention of this application is the same as the first invention, except that the foreign substances included are metals, organic molecules, organometallic compounds, magnetic substances, semiconductors, superconductors, complexes, gases, and inorganic solids. Hybrid single-walled carbon nanotubes, which are characterized in that they are at least one compound or two or more types of compounds.Hybrid single-walled, characterized in that the contained foreign substance is a metal-encapsulated fullerene. Fourth, the present invention also provides a carbon nanotube, and fourthly, a hybrid single-walled carbon nanotube characterized in that the contained foreign substance is a toxic gas. BRIEF DESCRIPTION OF THE FIGURES

In Figure 1, (a) was isolated in _{_{(G d @ C 82) n}} @ S WN T, (b) is exemplified HRTEM image of _{_{(G d @C 82) n @}} S WN T of bundle the Figure der Li, (c) is a schematic diagram illustrating a structure of a SWN T containing therein the metal-encapsulated fullerene _{_{(G d @ C 82) n}} @ SWN T.

FIG. 2 (a) is a diagram illustrating an HRT EM image of a bundle SWNT composed of several hundred SWNTs, and FIG. 2 (b) is a diagram illustrating an electron diffraction pattern of the bundle SWNT, (C) illustrates a diagram obtained by Fourier-transforming the HRT EM image (a).

Figure. 3 (a), the number bundles _{_{(G d @C 82) n @}} S WN T electron energy of - N (4 d) the absorption edge of the G d of spectra obtained by loss spectroscopy (~ 1 4 5 e V) and the K (Is) absorption edge (~ 285 e V) of carbon, (b) is the M (3 d) absorption edge of Gd obtained from the same sample as (a). FIG. BEST MODE FOR CARRYING OUT THE INVENTION

The invention of this application has the features described above, and the embodiment will be described below.

First, the hybrid single-walled carbon nanotube provided by the invention of the present application is characterized in that a foreign substance is included in a cavity in a cylinder of SWNT.

As the substance to be included, any one or more of metals, organic molecules, organometallic compounds, magnetic substances, semiconductors, superconductors, complexes, gases, inorganic solid compounds, and the like can be selected. .

For example, metals such as lead, tin, copper, indium, mercury, and alkali Various metals such as metals and transition metals and their compounds, as organic molecules, aromatic compounds such as naphthalene, anthracene, phenanthrene, pyrene, and perylene; organic molecular semiconductors; and organic dye molecules such as cyanine dyes and beta-carotene. Further, carbon clusters such as fullerenes and super-fullerenes, metal-encapsulated fullerenes in which these include metal atoms, and organometallic compounds represented by Fevacene, etc. can be used. Elements such as samarium, gadolinium, lanthanum, iron, cobalt, nickel, and mixtures thereof are used as the magnetic material, and silicon, germanium, gallium arsenide, zinc selenide, zinc sulfide, etc. are used as semiconductors. Elements such as lead, tin, and gallium can be used as the superconductor, and organometallic complex / inorganic metal complex, hydrogen, boron, nitrogen, oxygen, and the like can be used. Examples of the gas include gases such as carbon oxide, nitric oxide, inert gas and toxic gas, silane, disilane, germane, dichlorosilane, arsine, phosphine, hydrogen selenide, hydrogen sulfide, triethylgallium, dimethylzinc, It is also possible to use hydrides, chlorides, fluorides, alkoxy compounds, alkyl compounds and gaseous substances composed of a combination of the desired elements such as hexafluorotungsten.

Of the above substances, metal-encapsulated fullerenes are C ₆ . Unlike molecules, it is a semiconductor with a narrow band gap, and it is known that the band gap takes various values depending on the number of contained metal atoms. If such metal-encapsulated fullerenes can be encapsulated in SWNTs, it will provide a more interesting composite material.

The hybrid single-walled carbon nanotube of the invention of this application has a structure in which the above-described foreign substances are arranged in a cavity in a cylinder of SWNT like beans in a sheath. Since these foreign substances are relatively stably arranged in the SWNT, they are stable even if they were unstable in the air in the past. There is a high possibility that they can be stored or used, and there is a possibility that harmful things will be stored or used without harm.

Therefore, examples will be shown below, and the embodiments of the present invention will be described in more detail. Example

(Example 1)

The G d @C ₈₂ and S WN T is the starting material closely sealed put into a glass ampoule, and held at 500 ° C 24 h, as the reaction product of the invention of this application _{_{(G d @ C 82) n}} @ S WNT was obtained.

Using the obtained (G d @ C ₈₂ ) _n @SWNT as a sample, observation was performed with a high-resolution transmission electron microscope (HRT EM) equipped with an electron energy loss spectrometer. The sample is ultrasonically dispersed in hexane, and the suspension is dropped on a microgrid of an electron microscope.Image observation is performed at a setting of 120 kV and spectroscopic measurement is performed at a setting of 117 kV. Was performed.

<A> FIGS. 1 (a) and 1 (b) show HRTEM images of (G d @ C ₈₂ ) _n @SWNT. FIG. 1C illustrates a structural model of (G d @ C ₈₂ ) _n @S WNT.

1 from (a), is in SWANT s was found that G d @ C ₈₂ is Nde parallel in a row in a chain. The SWNTs with the metal-encapsulated fullerenes in a chain further included therein had a diameter of 1.4 to 1.5 nm. Also, as shown in Fig. 1 (a), a dark area was found inside most of the _C82 molecular shell. This dark area is C _6, which has nothing in the fullerene cage. Since it is not observed in the case of a molecule, it can be said that it corresponds to the Gd atom included in the _C82 molecule. Therefore, without G d @C ₈₂ molecules decompose or react, it is directly included in the S WN T I understand.

The G d atom in the fullerene cage included in SWNT was located off center of the fullerene cage _C82 molecule. The fact that the metal atoms contained in the fullerene cage appear at certain positions confirms that the fullerene cage contained in SWNT does not rotate at room temperature.

As shown in Fig. 1 (b), many bundled SWNTs were also obtained, and the average distance between the centers of the tubes (corresponding to d in Fig. 1 (c)) was 1.64 η. m or less.

In <B> FIG. 2 (a), the exhibited hundreds bundled consisting SWN T of _{_{(G d @C 82) n @}} S WN T HRTEM images. Although cylindrical inner void is present also a bunch of empty SWNT, almost all bundled SWN T it was confirmed that the enclosing G d @C ₈₂ full cylindrical inner void. These were also proved, for example, by the electron diffraction pattern of a bundle of SWNTs as illustrated in Fig. 2 (b).

Also, from the electron diffraction image in Fig. 2 (b), a sharp line that forms a striped pattern perpendicular to the nanotube bundle axis can be observed, which is due to the intermolecular distance between adjacent Gd @ _C82 molecules. match, intermolecular distance G d @C ₈₂ molecules to each other is confirmed to be uniform in each of the S WN T bundle. This was confirmed by Fourier transforming and analyzing the HRTEM image as shown in Fig. 2 (c). The rings seen in both patterns correspond to reflections (~ 0.214 nm) from the Daraphyte (100) plane. The points aligned perpendicular to the axis of the bundled SWNT correspond to the center-to-center distance (d) of the hexagonal closest packed SWNT.

G d @ C ₈₂ molecules in SWN T from that are arranged at a distance between certain molecules chain G d, which is included in the SWN T @C ₈₂ one-dimensional It can be regarded as a crystal. The measured interatomic distance (a) was 1.10 ± 0.03 nm. From the results of synchrotron X-ray diffraction analysis, the interatomic distance of a three-dimensional molecular crystal assumed to have C ₂ V-type molecular symmetry (for example, when Sc-encapsulated fullerene Sc @ C ₈₂ is 1.124 nm ), Or slightly smaller. Note that C _{6 in} SWNT can be regarded as a one-dimensional crystal. And C _7. Were ~ 0.97 nm and ~ 1.02 nm, respectively.

<C> It was confirmed that Gd @ _C82 was also introduced into the SWNT located at the center of the SWNT bundle, as was the SWNT located at the periphery. This was confirmed for all other inclusions. Since it is unlikely that the encapsulated material will diffuse from the SWNT outside the bundle to the central SWNT, the inclusion is likely to occur at the capped end of the SWNT.

Shows the results of <D> Number bundles of the _{_{(G d @C 82) n @}} SWN T analyzed by electron energy loss spectroscopy in Figure 3 (a). In Fig. 3 (a), the N (4d) absorption edge of Gd (~ 145 eV) and the K (1 s) absorption edge of carbon (~ 285 eV) were confirmed. Since the (I s) absorption edge of carbon is due to both fullerene and SWNT carbon, it exhibited a sharp 7T * bond peak and a broad * bond peak around 299 eV. .

When the two absorption edges of N (4 d) and K (1 s) were averaged using an appropriate scattering cross section, the atomic ratio (G d / C) between 〇 and 〇 was approximately 0.0 (± 0.0004 7). As can be seen from the above observations, this value is due to the fact that Gd @ _C82 is arranged at an interatomic distance of 1.1 nm in SWNT with a diameter of 1.4 nm (Gd @ _C82 ) _n @ This value is very close to the calculated value obtained for SWNT, 0.00037. And from this, the (G d @C ₈₂ ) _n @ SWNT bundle used in this observation The filling factor of G d @C ₈₂ was estimated to be approximately 68%.

Fig. 3 (b) shows the M (3d) absorption edge of Gd obtained from the same sample as above. In general, the position of the M (3d) peak of a lanthanoid metal can be used to identify the valence state, and the amount of charge transfer can be known from the result. Figure 4 (b), the highest peak position _{_{(G d @ C 82) n}} @ M 5 Contact and M ₄ absorption edge of SWNT were respectively 1 1 84 e V and 1 2 1 4 e V. These peak positions, since exactly match the peak positions of the G d ₂ 0 ₃ is a reference spectrum, G d atom which is contained in _{_{(G d @ C 82) n}} @ S WNT the trivalent state Proven to be. In one hand, it G d ^{3 +} @ 〇 ₈₂ ³ _ bulk G d atom that is contained in the crystal is the same spin state as G d atom _{_{^{G d 2 0 3 (8 S}}} 7/2) is already confirmed ing. From these, the valence state of the G d atom which is contained in G d @C ₈₂ does not change before and after being included in the SWNT, for example, ^{_{_{(G d 3 + @C 8 2}}} 3 _) n @ It can be seen that the state is SWNT.

<E> be present since (G d @C ₈₂₎ _n @ valence state of C ₈₂ Fuller Rengeji in SWN T is not disclosed, but the above results, the fullerene cage from G d atom Alternatively, the possibility of charge transfer to SWNT was suggested. In TEM observation, (G d) is larger than ( _N d) than SWN with metal-free fullerene, such as (C ₆₀ ) _n @ SWN T or (C ₇₀ ) _n @ SWNT. @C ₈₂ ) _n @SWNT was found to be more easily broken by electron beam irradiation. These are important findings about the chemical properties of nanotubes containing metal-encapsulated fullerenes.

(Example 2)

Sm @ C ₈₂ , Sc ₂ @C ₈₄ , and La ₂ @C ₈ as foreign substances included. , S c ₃ N @ C _68, etc. and the metal-containing fullerene, C _7. , C ₇₆ , C ₈ . , C _{8 2,} C _{8 4} hollow fullerene like, even if using a variety of materials such as Hue spout, hype lid carbon Nanochi Yubu containing therein these impurities could be obtained confirmed similarly.

Of course, the present invention is not limited to the above-described example, and it goes without saying that various aspects are possible in detail. Industrial applications

As described in detail above, according to the present invention, a new hybrid single-walled carbon nanotube that has the potential to be used in a wide range of fields such as information and communication and the chemical industry, because various substances can be included in the space inside the cylinder Is provided.

Claims

The scope of the claims

1. A hybrid single-walled carbon nanotube characterized in that a foreign substance is included in a cavity in the cylinder of the single-walled carbon nanotube.

2. Encapsulated foreign substances must be one or more of carbon clusters, metals, organic molecules, organic metal compounds, magnetic materials, semiconductors, superconductors, complexes, gases, and inorganic solid compounds. 2. The hybrid single-walled carbon nanotube according to claim 1, which is characterized in that:

3. The hybrid single-walled carbon nanotube according to claim 1, wherein the encapsulated foreign substance is a metal-encapsulated fullerene.

4. The hybrid single-walled carbon nanotube according to claim 1, wherein the foreign substance contained is a toxic gas.