JPH10324513A - Production of metal-containing carbon cluster - Google Patents

Abstract

PURPOSE: To enhance the productivity of a metal-contg. carbon cluster, to facilitate collection and to increase the kinds of metallic compds. by pulverizing a metallic element-contg. oxide and a powdery carrier in an org. solvent and carrying out drying, heating in an atmosphere of a hydrogen-contg. reducing gas and heating in a vacuum. CONSTITUTION: A metal oxide and a powdery carrier, preferably alumina, zirconia or manganese oxide are pulverized in an org. solvent to stick the metal oxide of about several μm to the surface of the carrier. The metal oxide is reduced by heating in an atmosphere of a hydrogen-contg. reducing gas and the objective metal-contg. carbon cluster is formed from carbon atoms fed from the adsorbed residual org. solvent or graphite by heating in a vacuum. For example, alumina powder having 20-400 nm diameter is mixed with tungsten oxide powder having several μm diameter and alcohol. After pulverization, the resultant tungsten doped alumina powder 4 with occluded alcohol is put in a graphite vessel 1, the vessel 1 is set in a carbon fiber vessel 3 and the powder 4 is heated with a carbon heater 2 while blowing hydrogen-contg. gaseous Ar.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel carbon compound or a novel metal compound and a method for producing the same, and more particularly, to a magnetic recording medium such as a magnetic disk or a magnetic tape and an insulator, a semiconductor, a conductor, or The present invention relates to a method for producing a metal-containing carbon cluster which is an electronic material such as a superconductor or a chemical material such as a catalyst or a gas occlusion.

[0002]

2. Description of the Related Art In 1990, Kretschmer et al.
A cage-like hollow carbon cluster as represented by 60;
The so-called mass synthesis method of fullerenes was announced (Kretschmer et al., Nature (W. Kratzmer et al., Natu
re). In particular, K3 doped with K in a C60 thin film by Hebard et al.
Report that C60 exhibited superconductivity at critical temperature Tc = 18K (Hebard et al., Nature (AFHebard e)
t al., Nature), 350 (1991) 600) attracted attention as a discovery of new superconductors. Since then, many research institutions have conducted research aimed at increasing the superconducting transition temperature. At present, Cs2RbC60 has reached Tc = 33K.
(K. Tanigaki et al., Nature), 352
(1991) 222).

More recently, the synthesis of an organic ferromagnet composed of tetrakis (dimethylamino) ethylene and C60 has been described.
(Armand et al., Science (PMAllemand et
al., Science), 253 (1991) 301), and the production of carbon tubes made of graphite in a cylindrical shape (Iijima, Nature (S. Iijima, Nature), 354 (1991) 56). It is starting to show.

[0004] As described above, carbon clusters and fullerenes have received great attention as new industrial materials such as electronics. Hereinafter, the carbon cluster is used as a general term for the fullerenes, carbon tubes, and general carbon aggregates.

[0005] On the other hand, since such a carbon cluster has a cage structure, even a metal-encapsulated carbon cluster in which atoms, molecules, or ions are encapsulated, is a new compound and a new material as never before. Expectations are high. To date, a small group of La @ C82 containing La has been obtained by a group of Smalley et al. Of Rice University (Yan Chai et al., J. Phys. Ch.
em.), 95 (1991) 7564) and a report of C82 containing three Sc by the group of Shinohara et al. of Mie University (H. Shinohara et al., Nature), 357 (1992)
52).

[0006]

The above-described method for producing a metal-containing carbon cluster uses a laser evaporation method or an electric heating method as described below.

(1) In the laser evaporation method, a metal impregnated carbon cluster is evaporated by irradiating a graphite impregnated with a metal halide to be confined by laser irradiation. As a result, only a small quantity of 10 4 to 10 5 pieces can be obtained per pulse, and collection is difficult.

(2) In the current heating method, La2O3 is put in a carbon rod used for arc discharge in advance, and a DC current of about 25 V and 100 A is applied to generate the same as in a normal fullerene mass synthesis method. In this case also, only a small amount of La-containing C82 is obtained.

As described above, according to the current method, the amount of the metal-encapsulated carbon clusters obtained is very small and difficult to collect, and the types of metal compounds that penetrate into graphite are limited, so that the desired metal is confined in the carbon clusters. It was difficult.

An object of the present invention is to provide an efficient method for producing a metal-containing carbon cluster which can avoid or improve the above-mentioned problems.

[0011]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
This is achieved by mixing the oxide of the desired metal to be included with the support powder in the presence of an organic solvent, reducing the mixture, and then heating in vacuum. As the support powder, alumina, zirconia oxide and manganese oxide are preferred.

[0012]

According to the method of the present invention, an oxide containing a desired metal element to be encapsulated in a carbon cluster is mixed with a support powder in the presence of an organic solvent, reduced, and then heated in a vacuum to form an ordinary powder. A metal-containing carbon cluster containing a metal in addition to fullerenes can be obtained efficiently. The exact reason for this has not been elucidated, but he speculates as follows.

That is, the conventional manufacturing method basically promotes the generation of active species such as carbon clusters, metal atoms or metal ions by using current heating or laser sputtering of carbon. However, in these conventional methods, the active species described above are in a state of spatially diverging, and it is considered that there is a high possibility that a sufficient collision probability cannot be obtained to generate a desired metal-containing carbon cluster.

On the other hand, according to the present invention, after a metal oxide of about several microns is attached to the surface of the support powder and reduced, the metal-encapsulated carbon cluster is adsorbed by the adsorbed resident organic solvent or carbon atoms supplied from graphite. Is assumed to be generated.

[0015]

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

Example 1 92 g of alumina (Al2O3) powder having a diameter of 20 nm to 400 nm, 8 g of tungsten oxide (WO3) powder having a diameter of about several μm and 200 ml of alcohol were mixed and pulverized by a ball mill for 24 hours. Then, the obtained tungsten-doped alumina powder occluded alcohol,
In a graphite container 1 shown in FIG. 1, the container was placed in a carbon fiber container, and heated at 700 ° C. for 2 hours by a carbon heater 2 while blowing argon gas containing 3% hydrogen gas under normal pressure. Thereafter, it was heated at 780 ° C. for 1 hour under a vacuum of 10-7 torr. Observation of the obtained sample with an electron microscope confirmed the existence of a spherical carbon cluster having a diameter of about 5 nm. About 3 nm tungsten was confirmed at the center in about half of the carbon clusters. Tungsten atoms exist as clusters, and the lattice spacing is
It was 0.22 nm. It is consistent with the lattice spacing of tungsten. The presence of the element was also confirmed by X-ray energy analysis. It is considered that the spherical carbon cluster is composed of multiple layers of spheres.

Therefore, from the above results, it was found that metal-encapsulated carbon clusters were formed on the alumina surface.

The obtained metal-containing carbon cluster was taken out of the vacuum, exposed to the air, and further observed in a vacuum. As a result, no metal-containing carbon cluster was observed, and it was found that the metal-containing carbon cluster was stable in the air.

Example 2 As in Example 1, a study was conducted using nickel oxide (NiO) as a metal oxide as a raw material. As a result, it was found that a nickel element-containing carbon cluster was formed as in Example 1.

[0020]

According to the present invention, a desired metal-containing carbon cluster can be produced by subjecting a support powder mixed with a metal oxide of a desired metal element to be included to a heat treatment.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing the structure of an apparatus used for producing a metal-containing carbon cluster according to the present invention.

[Explanation of symbols]

1: graphite container, 2: carbon heater, 3: carbon fiber, 4: tungsten-doped alumina powder containing alcohol, 5: carbon support block.

Continued on the front page (71) Applicant 000233240 Hitachi Instrument Engineering Co., Ltd. 312 832 Nagakubo, Horiguchi, Hitachinaka-shi, Ibaraki Prefecture (72) Inventor Akio Taniguchi 2520 Akanuma, Hatoyama-cho, Hiki-gun, Saitama Japan Basic Research, Hitachi, Ltd. In-house (72) Inventor Koichi Niihara 3-18-1-608 Yamadahigashi, Suita-shi, Osaka (72) Inventor Atsushi Nakahira 1-2 Aoyamadai, Suita-shi, Osaka C33-307 (72) Inventor Toru Sekino Osaka 2-2-3-341 Nishi Midorioka, Toyonaka-shi (72) Inventor Takeo Ueno 832 Nagakubo, Horiguchi, Hitachinaka-shi, Ibaraki 2 Hitachi Measurement Engineering Co., Ltd.

Claims (4)

[Claims] In a method for producing a metal-encapsulated carbon cluster containing at least one metal element inside a carbon cluster, an oxide containing the metal element and a support powder are pulverized in an organic solvent and dried. A method for producing a metal-containing carbon cluster, comprising heating in a reducing gas atmosphere containing hydrogen and then heating in a vacuum. 2. The method for producing a metal-containing carbon cluster according to claim 1, wherein the mixing ratio of the metal oxide to the support powder is 1% to 50% by weight. 3. The method for producing a metal-containing carbon cluster according to claim 1, wherein the support powder is an alumina powder. 4. The method according to claim 1, wherein the metal oxide is tungsten, molybdenum,
The method for producing a metal-encapsulated carbon cluster according to claim 1, wherein the method is an oxide of nickel, titanium, niobium, iron, cobalt, or zirconia, or a composite oxide thereof.