JP2008038218A - Sputtering apparatus with multiangular barrel, surface-modified carbon material and production method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sputtering apparatus with a multiangular barrel, which can make the outer surface of a carbon carrier carry many catalytic fine particles thereon; a carbon-supported catalyst; and a production method therefor. <P>SOLUTION: The sputtering apparatus with the multiangular barrel comprises: a vacuum vessel 1 of which the inner part has a polygonal shape in a cross section cut along an approximately parallel direction to gravity; a dispersing member which is accommodated in the vacuum vessel and disperses secondary particles formed by the agglomeration of primary particles of a carbon carrier 3 into the primary particles or secondary particles smaller than the original secondary particles; a rotating mechanism for rotating the vacuum vessel around a rotation axis which is approximately vertical to the cross section; and a sputtering target 2 arranged in the vacuum vessel. The production method includes carrying out a sputtering operation to make the carbon carrier 3 carry fine particles or a thin film on the surface, while dispersing the secondary particles of the carbon carrier 3 by the dispersing member while stirring or rotating the carbon carrier 3 in the vacuum vessel 1 by rotating or swinging the vacuum vessel with the use of the rotating mechanism. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polygonal barrel sputtering apparatus capable of supporting many fine particles or thin films on the outer surface of a carbon support, a surface-modified carbon material, and a method for producing the same.

  A fuel cell is a new power generation system that directly converts energy generated by electrochemical reaction of a fuel gas and an oxidant gas into electric energy, and is a molten carbonate electrolyte fuel cell that operates at a high temperature (500 to 700 ° C.). , A phosphoric acid electrolyte fuel cell operating at around 200 ° C., an alkaline electrolyte fuel cell operating at room temperature to about 100 ° C. or less, and a polymer electrolyte fuel cell.

  Examples of the polymer electrolyte fuel cell include a hydrogen ion exchange membrane fuel cell (Proton Exchange Membrane Fuel Cell: PEMFC) that uses hydrogen gas as a fuel and a direct methanol fuel that is used by supplying liquid methanol directly to the anode as a fuel. There is a battery (Direct Methanol Fuel Cell: DMFC).

  In order to increase the energy density of fuel cells and improve the output density and output voltage, research is actively conducted on electrodes, fuel, and electrolyte membranes. In particular, the activity of the catalyst used in the electrodes is to be improved. There are many attempts. In general, Pt, Pt, and Pt alloys are frequently used as catalysts used in PEMFC and DMFC, but it is preferable to reduce the amount of catalyst used in order to ensure price competitiveness. As a method of reducing the amount of catalyst while maintaining or increasing the performance of the fuel cell, a conductive carbon material having a large specific surface area is used as a support, and Pt is dispersed in a fine particle state in this to form an electrochemical catalyst metal particle. A method of increasing the active surface area is used.

  The activity of the catalyst improves as the electrochemically active surface area of the catalyst increases. In order to increase the active surface area, the amount of the supported catalyst may be simply increased, but in this case, the amount of the carbon support to be used increases together, so that the thickness of the electrode also increases. For this reason, problems such as an increase in internal resistance of the electrode and difficulty in forming the electrode occur. Therefore, it is required to increase the concentration of the supported catalyst while keeping the amount of the carrier used constant.

Hereinafter, a conventional method for producing a surface-modified carbon material will be described.
The step of impregnating carbon nanotubes, which are carbon supports, with a solvent and a precursor of platinum, which is the finally supported catalyst metal, is impregnated twice or more, and the catalyst metal precursor is impregnated during the impregnation step. The method includes a step of drying the carbon support and a step of reducing the carbon support.

  More specifically, the method for producing the surface-modified carbon material includes: (a) impregnating a carbon support with a metal precursor solution in which a part of a precursor of platinum, which is a catalyst metal that is finally supported, is mixed. A first impregnation step, (b) a first drying step for drying the carbon support impregnated with the catalyst metal precursor, and (c) a first reduction for reducing the carbon support impregnated with the catalyst metal precursor. And (d) a second impregnation step in which the carbon support pre-impregnated with the catalyst metal particles is impregnated again with a metal precursor solution in which the solvent and the remainder of the catalyst metal precursor to be finally supported are mixed. (E) a second drying step of drying the catalyst metal precursor and the carbon support impregnated with the catalyst metal particles; and (f) the catalyst metal precursor and the carbon support impregnated with the catalyst metal particles. A second reduction stage to reduce Than (for example, see Patent Document 1).

Japanese Patent Laying-Open No. 2005-108838 (paragraphs 0027 and 0029 to 0030)

  In the conventional method for producing a surface-modified carbon material, an impregnation method is used as a method for supporting platinum as a catalyst metal on a carbon nanotube. In this impregnation method, as described above, the carbon nanotube is impregnated with the metal precursor solution, so that the metal precursor solution is sucked into the carbon nanotube tube by the capillary effect, and finally, a large amount of platinum is outside the carbon nanotube. Without being carried in the tube. Thus, when a large amount of platinum is supported inside the outside of the carbon nanotube, much of the platinum in the tube is wasted because most of the platinum in the tube is not used as an electrode catalyst. Therefore, development of a method for supporting a large number of catalyst fine particles on the outer surface of a carbon support such as a carbon nanotube is required.

  The present invention has been made in consideration of the above-described circumstances, and its purpose is to provide a polygonal barrel sputtering apparatus capable of supporting many fine particles or thin films on the outer surface of a carbon support, a surface-modified carbon material, and a method for producing the same. It is to provide.

  In order to solve the above-mentioned problems, attention was paid to a sputtering method which is one of physical vapor deposition methods which does not cause a capillary effect. This method is considered to be very versatile for reasons such as selecting a carrier, being able to modify the surface of the carrier from metal to inorganic, and having a low environmental load. This time, we invented the polygonal barrel sputtering method. In this method, the carbon support is agitated or rotated by rotating a polygonal barrel containing the carbon support, and a large number of fine particles or thin films are supported on the outer surface of the carbon support.

This will be specifically described below.
The polygonal barrel sputtering apparatus according to the present invention is a vacuum container that contains a carbon carrier, and the internal shape of a cross section substantially parallel to the direction of gravity is a polygon,
A dispersion member that is placed in the vacuum vessel and disperses secondary particles formed by agglomerating primary particles of the carbon carrier into primary particles or secondary particles smaller than the original secondary particles;
A rotation mechanism that rotates the vacuum vessel about a direction substantially perpendicular to the cross section as a rotation axis;
A sputtering target disposed in the vacuum vessel;
Comprising
The carbon carrier in the vacuum vessel is agitated by performing a rotation operation that rotates the vacuum vessel in one direction using the rotation mechanism, or a pendulum operation that repeats the rotation operation in the opposite direction after rotating in one direction. Alternatively, sputtering is performed while dispersing the secondary particles of the carbon support by the dispersion member while rotating, thereby supporting fine particles or a thin film on the surface of the carbon support.
The pendulum operation is an operation that repeats an operation of rotating at a rotation angle of 180 ° or less or more than 180 ° in one direction and rotating at a rotation angle of 180 ° or less or more than 180 ° in the opposite direction.

According to the polygon barrel sputtering apparatus, fine particles or a thin film is supported on the surface of the carbon support by sputtering. Since sputtering has directivity and no capillary effect, many fine particles or thin films can be supported on the outer surface of the carbon support.
In addition, the carbon carrier itself and the dispersion member are both rotated by rotating or pendulating the vacuum vessel itself with a substantially vertical direction (that is, substantially horizontal direction) as a rotation axis with respect to a cross section substantially parallel to the direction of gravity. Stirring can be performed, and the cross-sectional shape inside the vacuum vessel is made polygonal, so that the carbon carrier and the dispersion member can be periodically dropped by gravity, and the carbon carrier can collide with the inner wall of the vacuum vessel. For this reason, stirring efficiency can be improved dramatically, aggregation of the carbon support can be prevented, and in addition, the aggregated carbon support can be stirred while being dispersed by the dispersing member. That is, the stirring by the rotation operation or the pendulum operation and the dispersion of the aggregated carbon support can be performed simultaneously and effectively. Therefore, fine particles having a relatively small particle size can be carried on the carbon support.

  In the polygon barrel sputtering apparatus according to the present invention, it is preferable that the dispersion member includes at least one of a powdery substance, a rod-like substance, a small piece, a spherical substance, and a substance having a plurality of protrusions.

  The polygonal barrel sputtering apparatus according to the present invention may further include a vibrator that applies vibration to the vacuum vessel. Thereby, it becomes possible to prevent aggregation more effectively.

  The polygonal barrel sputtering apparatus according to the present invention may further include a heater for heating the carbon carrier in the vacuum vessel. For example, when the inside of the vacuum vessel is evacuated, by heating the vacuum vessel with a heater, moisture adsorbed in the vacuum vessel and on the surface of the carbon support can be vaporized and exhausted. Therefore, since water can be removed from the inside of the vacuum container, aggregation of the carbon support can be prevented more effectively.

The method for producing a surface-modified carbon material according to the present invention is formed by agglomerating the carbon support and the primary particles of the carbon support in a vacuum vessel having a polygonal internal shape in a cross section substantially parallel to the direction of gravity. Containing a dispersing member for dispersing secondary particles into primary particles or secondary particles smaller than the original secondary particles;
By performing a pendulum operation that repeats a rotation operation in which the vacuum vessel is rotated in one direction with a substantially vertical direction as a rotation axis with respect to the cross section, or an operation in which the vacuum vessel is rotated in the opposite direction after being rotated in one direction. Sputtering is performed while dispersing the secondary particles of the carbon support by the dispersing member while stirring or rotating the carbon support inside, thereby supporting fine particles or a thin film on the surface of the carbon support.

  In the method for producing a surface-modified carbon material according to the present invention, the carbon support includes single-wall carbon nanotubes (SWNT), double-wall carbon nanotubes (DWNT), and multi-wall carbon. Multi-wall carbon nanotubes (MWNT), carbon nanohorns, carbon nanocoils, cup-stacked carbon nanotubes, bamboo-like carbon nanotubes, vapor-grown carbon fibers (VGCF), carbon nanofibers, graphite nano It is preferably at least one of fiber, fullerene, carbon black and carbon single crystal.

  In the surface-modified carbon material according to the present invention, a vacuum container having a polygonal cross-sectional shape is rotated in one direction about a direction substantially perpendicular to the cross-section as a rotation axis, or rotated in one direction. By performing a pendulum operation that repeats the operation of rotating in the opposite direction later, by performing sputtering while stirring or rotating the carbon carrier in the vacuum vessel, fine particles or thin films were supported on the outer surface of the carbon carrier. It is characterized by.

  In the surface-modified carbon material according to the present invention, it is preferable that the carbon support is a carbon nanotube, and more fine particles or thin films are supported on the outer surface of the tube than in the tube of the carbon nanotube.

  In the surface-modified carbon material according to the present invention, it is preferable that almost 100% of the fine particles or thin film supported on the carbon nanotubes are supported on the outer surface of the tube.

  As described above, according to the present invention, it is possible to provide a polygonal barrel sputtering apparatus, a carbon-supported catalyst, and a method for producing the same that can support a large number of catalyst fine particles on the outer surface of a carbon support.

Embodiments of the present invention will be described below with reference to the drawings.
(Embodiment 1)
FIG. 1 is a configuration diagram showing an outline of a polygonal barrel sputtering apparatus according to Embodiment 1 of the present invention. This polygonal barrel sputtering apparatus is an apparatus for supporting catalyst fine particles having a relatively small particle diameter (an example of particle diameter; 1 to 100 nm, more preferably 1 to 3 nm) on the surface of a carbon support 3 made of carbon nanotubes. . Moreover, if this apparatus is used, by controlling the sputtering conditions such as argon flow rate (total pressure), high frequency output, sputtering time, temperature, etc., the particle diameter of the supported platinum fine particles can be easily in the range of about 1 to 100 nm, for example. Can be controlled.

  In the present embodiment, the catalyst fine particles are supported on the surface of the carbon support 3 made of carbon nanotubes. However, the present invention is not limited to this, and the catalyst fine particles are supported on the surface of the carbon support other than the carbon nanotubes. It is also possible. Specific examples of the carbon support include single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, carbon nanohorns, carbon nanocoils, cup-stacked carbon nanotubes, bamboo-shaped carbon nanotubes, vapor-grown carbon fibers, carbon nanofibers, Examples include graphite nanofiber, fullerene, carbon black, and carbon single crystal.

  The polygonal barrel sputtering apparatus has a vacuum vessel 1 for supporting catalyst fine particles on a carbon carrier 3, and this vacuum vessel 1 has a cylindrical portion 1a having a diameter of 200 mm and a hexagonal barrel (hexagonal cross section installed therein). Mold barrel) 1b. The cross section shown here is a cross section substantially parallel to the direction of gravity. In the present embodiment, the hexagonal barrel 1b is used. However, the present invention is not limited to this, and a polygonal barrel other than the hexagon can also be used.

In the hexagonal barrel 1b, secondary particles (size: for example, 100 nm to 100 mm) formed by agglomeration of primary particles of the carbon support 3 by moisture, electrostatic force, intermolecular force, etc. are regenerated as primary particles or original particles. A dispersion member (not shown) for dispersing the secondary particles smaller than the secondary particles is placed. This dispersion member disperses the carbon carrier 3 aggregated and collected in the vacuum vessel 1, and includes, for example, a powdery substance, a rod-like substance, a small piece, a spherical substance, and a substance having a plurality of protrusions. It is done.
The powdery substance has a size of about 0.1 to 5 mm, for example, and specific examples include sand and alumina powder.
The rod-like substance is a rod-like substance having a size of, for example, a length of about 1 to 50 mm and a thickness of about 0.1 to 10 mm. Specific examples include nails, wires, square bars, bolts, and the like. .
The small piece has a size of, for example, about 1 to 100 mm, and specific examples of the material include metals and resins.
The spherical material has a diameter of, for example, about 1 to 50 mm, and specific examples include iron balls, plastic balls, BB bullets, beads, and the like.
The substance having a plurality of protrusions has a size of about 10 to 50 mm and a large number of protrusions, and specific examples thereof include demon nuts.

The vacuum vessel 1 is provided with a rotating mechanism (not shown), and the rotating mechanism rotates the hexagonal barrel 1b in one direction (in the direction of the arrow), or the opposite direction after rotating in one direction. By performing a pendulum operation that repeats the operation of rotating in the direction opposite to the arrow, the carbon support 3 in the hexagonal barrel 1b is stirred or rotated to disperse the secondary particles of the carbon support by the dispersing member. The carrying process is carried out.
The original secondary particles have a size of 100 nm to 100 mm, for example.
In addition, the pendulum operation includes, of course, an operation of repeating an operation of rotating at a rotation angle of 180 ° or less in one direction and rotating at a rotation angle of 180 ° or less in the opposite direction, but 180 ° in one direction. It also includes an operation of repeating the operation of rotating at a super-rotation angle (for example, a rotation angle of 720 °) and rotating in the opposite direction at a rotation angle of over 180 ° (for example, a rotation angle of 720 °).

  A rotation axis when the hexagonal barrel is rotated by the rotation mechanism is an axis substantially parallel to the horizontal direction (perpendicular to the gravity direction). Further, a sputtering target 2 made of Pt is disposed on the central axis of the cylinder in the vacuum vessel 1, and the target 2 is configured so that the angle can be freely changed. As a result, when carrying the supporting process while rotating the hexagonal barrel 1b, the target 2 can be directed in the direction in which the carbon carrier 3 is positioned, thereby increasing the sputtering efficiency. In this embodiment, a Pt target is used. However, a material other than Pt (for example, Pd, Ni, etc.) can be supported on a carbon support. In that case, a target made of the supported material is used. It will be.

  One end of a pipe 4 is connected to the vacuum vessel 1, and one side of the first valve 12 is connected to the other end of the pipe 4. One end of the pipe 5 is connected to the other side of the first valve 12, and the other end of the pipe 5 is connected to the intake side of the turbo molecular pump (TMP) 10. The exhaust side of the turbo molecular pump 10 is connected to one end of the pipe 6, and the other end of the pipe 6 is connected to one side of the second valve 13. The other side of the second valve 13 is connected to one end of the pipe 7, and the other end of the pipe 7 is connected to the pump (RP) 11. The pipe 4 is connected to one end of the pipe 8, and the other end of the pipe 8 is connected to one side of the third valve 14. The other side of the third valve 14 is connected to one end of the pipe 9, and the other end of the pipe 9 is connected to the pipe 7.

  This apparatus includes a heater 17 for heating the carbon carrier 3 in the vacuum vessel 1. In addition, this apparatus includes a vibrator 18 for applying vibration to the carbon support 3 in the vacuum vessel 1. The apparatus also includes a pressure gauge 19 that measures the internal pressure of the vacuum vessel 1. In addition, the apparatus includes a nitrogen gas introduction mechanism 15 that introduces nitrogen gas into the vacuum vessel 1 and an argon gas introduction mechanism 16 that introduces argon gas into the vacuum vessel 1. In addition, this apparatus includes a high frequency application mechanism (not shown) that applies a high frequency between the target 2 and the hexagonal barrel 1b.

  Next, a polygon barrel sputtering method for supporting catalyst fine particles on the carbon carrier 3 using the polygon barrel sputtering apparatus and a method for producing a carbon supported catalyst will be described.

  First, about 0.03 gram of carbon support 3 is introduced into the hexagonal barrel 1b. As this carbon support 3, single-walled carbon nanotubes (SWNT) of CNI (registered trademark) Buckytubes were used. A nail was used as the dispersing member. Further, Pt was used for the target 2. In the present embodiment, carbon nanotubes are used. However, the present invention is not limited to this, and carbon carriers made of other materials can also be used. If this polygonal barrel sputtering method is used, fine particles can be supported on a wide range of carbon carriers.

Next, a high vacuum state was created in the hexagonal barrel 1b using the turbo molecular pump 10, and the pressure in the hexagonal barrel was reduced to 8 × 10 ⁻⁴ Pa. Thereafter, an inert gas such as argon or nitrogen is introduced into the hexagonal barrel 1b by the argon gas supply mechanism 16 or the nitrogen gas supply mechanism 15. The pressure in the hexagonal barrel at this time is about 0.8 Pa. In some cases, a mixed gas of oxygen and hydrogen may be introduced into the hexagonal barrel 1b. Here, about 90 ccm of argon gas is introduced into the hexagonal barrel 1b, and the argon pressure is about 30 Pa. Then, by rotating the hexagonal barrel 1b with a rotation mechanism for 30 minutes at an angle of 75 ° and 3.5 rpm, the carbon nanotubes 3 in the hexagonal barrel 1b are stirred and rotated to rotate the nail. The carbon nanotubes 3 are dispersed. At the same time, a high frequency output of, for example, 50 W is applied between the target 2 and the hexagonal barrel 1b by the high frequency application mechanism, so that Pt is sputter deposited on the surface of the carbon nanotube 3 at room temperature. At that time, the target is directed in the direction in which the carbon nanotube is located. In this way, Pt fine particles can be carried on the surface of the carbon nanotube 3.

  In this example, the pendulum operation at an angle of 75 ° is performed on the hexagonal barrel 1b. However, the present invention is not limited to this, and the angle of the pendulum operation can be changed to another angle. It is also possible to perform a rotating operation instead of a pendulum operation. Although the rotation speed of the pendulum operation is 3.5 rpm here, the rotation speed of the pendulum operation can be increased to about 20 rpm. In addition, although the high frequency output is 50 W here, the high frequency output can be increased to about 500 W. Here, the temperature at which the Pt fine particles are supported is room temperature, but the temperature can be raised to about 600 ° C.

  According to the first embodiment, the carbon nanotube itself can be rotated and stirred together with the nail by causing the hexagonal barrel itself to perform a pendulum operation or a rotation operation. Can be dropped regularly. For this reason, it is possible to dramatically improve the stirring efficiency, to prevent aggregation due to moisture, electrostatic force, and intermolecular force, and to stir the carbon nanotubes together with the nail. It can be stirred while being dispersed. That is, stirring by rotation and dispersion of the aggregated carbon nanotubes can be performed simultaneously and effectively. Therefore, Pt fine particles having a relatively small particle diameter can be carried on the carbon nanotube 3.

  In the present embodiment, Pt is supported on the surface of the carbon nanotube by sputtering. Since sputtering has directivity and no capillary effect, a large amount of Pt is not carried in the carbon nanotube tube as in the prior art. In other words, in the present embodiment, a large amount of Pt can be supported outside the inside of the carbon nanotube, or almost 100% of the Pt fine particles supported on the carbon nanotube can be supported on the outer surface of the tube. . Therefore, when the supported Pt is used as a catalyst, wasteful Pt of the supported Pt is reduced, and the catalyst efficiency can be dramatically increased.

  In the present embodiment, a heater 17 is attached to the outside of the vacuum vessel 1, and the hexagonal barrel 1 b can be heated to 600 ° C. by the heater 17. For this reason, when the inside of the vacuum vessel 1 is evacuated, by heating the hexagonal barrel with the heater 17, moisture in the hexagonal barrel can be vaporized and exhausted. Therefore, since water can be removed from the hexagonal barrel, aggregation of the carbon support can be prevented more effectively.

  In the present embodiment, a vibrator 18 is attached to the outside of the vacuum vessel 1, and the vibrator 18 can apply vibration to the powder 3 in the hexagonal barrel. Thereby, it becomes possible to prevent aggregation of the carbon support more effectively.

  In the present embodiment, since catalyst fine particles are supported on the surface of the carbon support 3 by the polygonal barrel sputtering method, it is not necessary to treat the waste liquid as in the impregnation method of the prior art, and the load on the environment can be reduced. There are advantages.

  In this embodiment, catalyst fine particles are supported on a carbon support, but fine particles or thin films other than catalyst fine particles can be supported on a carbon support.

  Further, since the carbon-supported catalyst manufactured by the manufacturing method according to the present embodiment supports Pt fine particles, it can be used for fuel cell electrode catalysts (anodes, cathodes) and industrial catalysts. Can be used for various surface-modified carbon materials other than fuel cell electrode catalysts and industrial catalysts. For example, industrial catalysts (aromatic hydrogenation, selective hydrogenation of unsaturated aldehydes, selective CO oxidation, selective hydrogenation of silicic aldehyde, NO decomposition, ammonia synthesis, hydrogenation of citral, hydrogenation of crotonaldehyde, etc.) It can be used for sensors, Li battery materials, photocatalysts, STM and SFM probes, field emitters, rubber and resin fillers, conductive resin fillers, and the like.

  In the first embodiment, vibration is applied to the carbon carrier 3 in the hexagonal barrel by the vibrator 18. However, instead of the vibrator 18 or in addition to the vibrator 18, a rod-shaped member is provided in the hexagonal barrel. It is also possible to apply vibration to the carbon support 3 by rotating the hexagonal barrel in the accommodated state. Thereby, it becomes possible to prevent aggregation of the carbon support more effectively.

  Next, electron microscope observation, EDX (energy dispersive X-ray analysis), XRD (X-ray diffraction method) of a sample (carbon-supported catalyst) in which Pt fine particles are supported on the outer surface of the carbon nanotube by the above-described carbon-supported catalyst production method The results of XRF (fluorescence X-ray analysis) will be described.

2 and 3 are photographs obtained by observing, with an electron microscope, a carbon-supported catalyst in which Pt fine particles are supported on the outer surface of a carbon nanotube by the manufacturing method according to the present embodiment.
As shown in FIGS. 2 and 3, it was confirmed that Pt fine particles were supported on the outer surface of the carbon nanotube. Specifically, it was confirmed that most of the Pt fine particles were supported on the outer surface of the carbon nanotube, and almost no Pt fine particles were supported inside the carbon nanotube tube.

  The Fe fine particles attached to the carbon nanotubes shown in FIG. 2 are not attached by the polygonal barrel sputtering apparatus according to the present embodiment, but are attached to the carbon nanotubes before carrying the Pt fine particles by the polygonal barrel sputtering apparatus. It was what was done. This is because, in the carbon nanotube production stage, Fe fine particles are used as seed crystals, and carbon nanotubes from which these seed crystals have not been removed are used in the present embodiment.

  FIG. 4 is a diagram showing the particle size distribution of Pt fine particles supported on the carbon supported catalyst shown in FIG. This figure measures the diameter of 100 randomly selected Pt particles in the photograph of FIG. 2, and shows the distribution of diameters from the measurement results. As shown in FIG. 4, the average value of the diameters of 100 Pt fine particles is 1.95 nm, and 90% of all particles are present between the particle diameters of 1.4 to 2.2 nm. Accordingly, it was confirmed that Pt fine particles having a uniform particle size were supported.

  FIG. 5 (A) is a diagram showing the result of analyzing the carbon nanotube before supporting Pt by EDX (energy dispersive X-ray analysis). FIG. 5B is a diagram showing a result of analyzing the carbon-supported catalyst in which the Pt fine particles are supported on the outer surface of the carbon nanotube by the manufacturing method according to the present embodiment by EDX.

  As shown in FIGS. 5A and 5B, it was confirmed that Pt fine particles were supported on the carbon nanotubes by a polygonal barrel sputtering apparatus.

  FIG. 6 is a diagram showing the results of analysis by XRD (X-ray diffraction method) of a carbon-supported catalyst in which Pt fine particles are supported on the outer surface of a carbon nanotube by the manufacturing method according to the present embodiment. As shown in this figure, it was confirmed that Pt fine particles were supported on the carbon nanotubes by a polygonal barrel sputtering apparatus. At the Pt (220) peak at 67.4 °, the particle size of Pt determined by Scherrer's equation is 1.85 nm, which almost coincides with the average particle size shown in FIG. 4 determined from the TEM photograph.

  FIG. 7 is a diagram showing a result of analyzing a carbon-supported catalyst in which Pt fine particles are supported on the outer surface of a carbon nanotube by XRF (fluorescence X-ray analysis) by the manufacturing method according to the present embodiment. As shown in this figure, it was confirmed that Pt fine particles were supported on the carbon nanotubes by a polygonal barrel sputtering apparatus.

(Embodiment 2)
A polygonal barrel sputtering method and a carbon-supported catalyst manufacturing method according to Embodiment 2 in which catalyst fine particles are supported on a carbon support 3 using the polygonal barrel sputtering apparatus shown in FIG. 1 will be described.

  First, about 0.5 gram of carbon support 3 is introduced into the hexagonal barrel 1b. As the carbon carrier 3, vapor grown carbon fiber (VGCF) manufactured by Showa Denko was used. A nail was used as the dispersing member. Further, Pt was used for the target 2.

Next, a high vacuum state was created in the hexagonal barrel 1b using the turbo molecular pump 10, and the pressure in the hexagonal barrel was reduced to 8 × 10 ⁻⁴ Pa. Thereafter, argon gas is introduced into the hexagonal barrel 1b by the argon gas supply mechanism 16. The argon gas flow rate at this time is about 20 ccm, and the argon gas pressure is about 0.8 Pa. Then, the rotating mechanism causes the hexagonal barrel 1b to perform a pendulum operation for 30 minutes at an angle of 75 ° and 3.5 rpm, thereby stirring and rotating the VGCF in the hexagonal barrel 1b and rotating the nail, which is agglomerated VGCF To disperse. At the same time, a high frequency output of, for example, 50 W is applied between the target 2 and the hexagonal barrel 1b by the high frequency application mechanism, so that Pt is sputter deposited on the surface of the VGCF at room temperature. At that time, the target is directed in the direction in which the VGCF is located. In this way, Pt fine particles can be supported on the surface of the VGCF.

  In the second embodiment, the same effect as in the first embodiment can be obtained.

  Next, the results of electron microscope observation, XRD (X-ray diffraction method) and XRF (fluorescence X-ray analysis) of a sample (carbon-supported catalyst) in which Pt fine particles are supported on the outer surface of VGCF by the above-described carbon-supported catalyst production method explain.

8 and 9 are TEM photographs of a carbon-supported catalyst in which Pt fine particles are supported on the outer surface of the VGCF by the manufacturing method according to the present embodiment, which is observed with an electron microscope.
As shown in FIGS. 8 and 9, it was confirmed that Pt fine particles having a relatively uniform particle size were uniformly supported on the outer surface of the VGCF.

  FIG. 10 is a diagram showing the particle size distribution of Pt fine particles supported on the carbon supported catalyst shown in FIG. This figure measures the diameter of 100 randomly selected Pt fine particles in the photograph of FIG. 8, and shows the distribution of diameters from the measurement result. As shown in FIG. 10, the average value of the diameters of 100 Pt fine particles is 2.1 nm, and 90% of all particles are present between 1.2 and 3.0 nm in particle size. Accordingly, it was confirmed that Pt fine particles having a uniform particle size were supported.

  FIG. 11 is a diagram showing the results of XRD (X-ray diffraction) analysis of a carbon-supported catalyst in which Pt fine particles are supported on the outer surface of VGCF by the manufacturing method according to the present embodiment. As shown in this figure, it was confirmed that Pt fine particles were supported on the VGCF by a polygonal barrel sputtering apparatus. Note that the graphite peak in FIG. 11 is attributed to VGCF, and is also observed in VGCF before supporting Pt. At the Pt (220) peak at 67.4 °, the particle size of Pt determined by Scherrer's equation is 2.3 nm, which almost coincides with the average particle size shown in FIG. 10 determined from the TEM photograph.

  FIG. 12 is a diagram showing the results of XRF (fluorescence X-ray analysis) analysis of a carbon-supported catalyst in which Pt fine particles are supported on the outer surface of VGCF by the manufacturing method according to the present embodiment. As shown in this figure, it was confirmed that Pt fine particles were supported on the VGCF by a polygonal barrel sputtering apparatus.

  Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, it is possible to appropriately change the supporting conditions for supporting the catalyst fine particles on the carbon support.

  In this embodiment, Pt is used as the material for the catalyst fine particles. However, the present invention is not limited to this, and other fine particles such as metals (Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Sr, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Tl, Pb, etc.) or non-metal (Si, As, C, etc.), the metal or non-metal alloy, or the metal or non-metal oxide, nitride, boride, carbide It is also possible to use.

It is a block diagram which shows the outline of the polygon barrel sputtering apparatus by Embodiment 1. FIG. 2 is a photograph of the carbon-supported catalyst according to Embodiment 1 observed with an electron microscope. 2 is a photograph of the carbon-supported catalyst according to Embodiment 1 observed with an electron microscope. It is a figure which shows the particle size distribution of the Pt fine particle carry | supported by the carbon carrying catalyst shown in FIG. (A) is a figure which shows the result of having analyzed the carbon nanotube before carrying | supporting Pt by EDX, (B) is a figure which shows the result of having analyzed the carbon carrying catalyst by Embodiment 1 by EDX. It is a figure which shows the result of having analyzed the carbon carrying catalyst by Embodiment 1 by XRD. It is a figure which shows the result of having analyzed the carbon carrying catalyst by Embodiment 1 by XRF. 4 is a TEM photograph of the carbon-supported catalyst according to Embodiment 2 observed with an electron microscope. 4 is a TEM photograph of the carbon-supported catalyst according to Embodiment 2 observed with an electron microscope. It is a figure which shows the particle size distribution of the Pt fine particle carry | supported by the carbon carrying catalyst shown in FIG. It is a figure which shows the result of having analyzed the carbon carrying catalyst by Embodiment 2 by XRD. It is a figure which shows the result of having analyzed the carbon carrying catalyst by Embodiment 2 by XRF.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Vacuum vessel 1a ... Cylindrical part 1b ... Hexagonal barrel 2 ... Target 3 ... Carbon support 4-9 ... Piping 10 ... Turbo molecular pump (TMP)
11 ... Pump (RP)
12-14 ... First to third valves 15 ... Nitrogen gas introduction mechanism 16 ... Argon gas introduction mechanism 17 ... Heater 18 ... Vibrator 19 ... Pressure gauge

Claims (9)

A vacuum vessel containing a carbon carrier and having a polygonal internal shape in a cross section substantially parallel to the direction of gravity; and
A dispersion member that is placed in the vacuum vessel and disperses secondary particles formed by agglomerating primary particles of the carbon carrier into primary particles or secondary particles smaller than the original secondary particles;
A rotation mechanism that rotates the vacuum vessel about a direction substantially perpendicular to the cross section as a rotation axis;
A sputtering target disposed in the vacuum vessel;
Comprising
The carbon carrier in the vacuum vessel is agitated by performing a rotation operation that rotates the vacuum vessel in one direction using the rotation mechanism, or a pendulum operation that repeats the rotation operation in the opposite direction after rotating in one direction. Alternatively, the multi-barrel sputtering apparatus is configured to carry fine particles or a thin film on the surface of the carbon support by performing sputtering while rotating the secondary particles of the carbon support with the dispersing member while rotating.   2. The polygonal barrel sputtering apparatus according to claim 1, wherein the dispersion member includes at least one of a powdery substance, a rod-like substance, a small piece, a spherical substance, and a substance having a plurality of protrusions.   3. The polygonal barrel sputtering apparatus according to claim 1, further comprising a vibrator that applies vibration to the vacuum vessel.   4. The polygonal barrel sputtering apparatus according to claim 1, further comprising a heater for heating the carbon carrier in the vacuum vessel. 5. In the vacuum vessel whose internal shape of the cross section substantially parallel to the direction of gravity is a polygon, the secondary particles formed by aggregating the carbon carrier and the primary particles of the carbon carrier from the primary particles or the original secondary particles. Contains a dispersion member to be dispersed in small secondary particles,
By performing a pendulum operation that repeats a rotation operation in which the vacuum vessel is rotated in one direction with a substantially vertical direction as a rotation axis with respect to the cross section, or an operation in which the vacuum vessel is rotated in the opposite direction after being rotated in one direction. A surface modification characterized by carrying fine particles or a thin film on the surface of the carbon support by carrying out sputtering while dispersing the secondary particles of the carbon support by the dispersing member while stirring or rotating the carbon support inside A method for producing a carbon material.   6. The carbon support according to claim 5, wherein the carbon support is a single-walled carbon nanotube, a double-walled carbon nanotube, a multi-walled carbon nanotube, a carbon nanohorn, a carbon nanocoil, a cup-stacked carbon nanotube, a bamboo-shaped carbon nanotube, a vapor grown carbon fiber, or a carbon nano A method for producing a surface-modified carbon material, which is at least one of fiber, graphite nanofiber, fullerene, carbon black, and carbon single crystal.   A pendulum that repeats a rotating operation of rotating a vacuum vessel having an internal cross-sectional shape of a polygon in one direction with a substantially vertical direction as a rotation axis with respect to the cross-section, or a rotating operation in the opposite direction after rotating in one direction A surface-modified carbon material wherein fine particles or thin films are supported on the outer surface of the carbon support by performing sputtering while performing stirring while rotating or rotating the carbon support in the vacuum vessel.   8. The surface-modified carbon material according to claim 7, wherein the carbon carrier is a carbon nanotube, and a larger amount of the fine particles or thin film is supported on the outer surface of the tube than in the tube of the carbon nanotube. 9. The surface-modified carbon material according to claim 8, wherein almost 100% of the fine particles or thin film supported on the carbon nanotubes are supported on the outer surface of the tube.