JP4939005B2 - Catalyst carrier and catalyst carrier for electrode catalyst of fuel cell - Google Patents

Description

  The present invention relates to a catalyst carrier, and more particularly to a catalyst carrier for an electrode catalyst of a fuel cell.

  Fuel cells are attracting attention as a highly efficient power generation system in harmony with the environment. In particular, solid polymer fuel cells that use proton-conducting solid polymers as electrolytes can operate at room temperature and achieve high output density, and are therefore highly expected as power sources for automobiles and stationary power sources. Yes. However, in order to put it into practical use and spread as a consumer power supply, it is important to further improve performance, improve durability, and reduce costs.

In general, an electrode of a polymer electrolyte fuel cell contains a noble metal such as platinum or a platinum alloy which is a catalytically active component, a conductive carbon material supporting the noble metal, and a polymer electrolyte, and efficiently performs an electrode reaction. In order to do so, it is said that it is necessary to efficiently form a three-phase interface. For example, at the hydrogen electrode (negative electrode), the following electrode reaction is performed using platinum as a catalytically active component.
H ₂ → 2H ⁺ + 2e ⁻

  In order to carry out an electrode reaction efficiently at the hydrogen electrode (negative electrode), hydrogen as a fuel is brought into contact with platinum supported on conductive carbon by utilizing gaps between conductive carbon particles as a carrier. At the same time as the reaction, it is necessary to move the generated hydrogen ions to the positive electrode using the polymer electrolyte as a medium, and to flow the generated electrons to the external circuit using the conductive carbon as a medium. Therefore, it is necessary to efficiently form the three-phase interface of the polymer electrolyte, hydrogen, platinum, and the support inside the electrode. When the three-phase interface is not formed, the electrode reaction efficiency (or catalyst utilization efficiency) can be increased. Can not. The same applies to the oxygen electrode (positive electrode).

  For example, Patent Literature 1 and Patent Literature 2 disclose techniques for increasing electrode reaction efficiency (or catalyst utilization efficiency). Patent Document 1 discloses that a noble metal is supported on carbon fine powder having pores having a diameter of 60 angstroms or less in a ratio of 20% or less with respect to all pores. Patent Document 2 discloses a catalyst active component ( It is disclosed that a specific fluorine-containing organic acid is impregnated or impregnated into activated carbon as a carrier supporting platinum), and a conductive agent and a fluorine-containing ion exchange resin are used in combination. Patent Document 3 discloses that a residue generated by fullerene extraction operation in a fullerene production process is used as a catalyst carrier. Currently, the factors that essentially affect durability are not clear.

At the oxygen electrode, water is generated by a reduction reaction of oxygen. Water causes clogging (flooding) within the electrode pores, impairing long-term stability. Hydrogen peroxide having strong oxidizing power may be generated, and oxygen may cause local heat generation on the catalyst. In Patent Document 4, an attempt is made to improve durability by controlling the specific surface area and the degree of graphitization by heat-treating carbon black or activated carbon.
Japanese Patent Laid-Open No. 2000-1000044 Japanese Patent No. 3446064 Japanese Patent Laid-Open No. 2004-223311 JP 2000-268828 A

  An object of the present invention is to provide a catalyst carrier that supports a catalytically active component such as a noble metal, improves the dispersibility of the catalytically active component, has a high catalytic activity, and is excellent in oxidation resistance. In particular, it is an object of the present invention to provide a catalyst carrier for a fuel cell electrode catalyst, which enhances the dispersibility of noble metals such as platinum, is excellent in power generation performance, and has excellent durability.

  The catalyst carrier of the present invention that has been able to solve the above-described problems is an activation treatment of an extraction residue obtained by substantially extracting at least a part of fullerene using a solvent from a fullerene-containing soot or a fullerene-containing soot, It contains a porous material obtained by high temperature heat treatment or high temperature heat treatment after activation treatment. When this porous material is used as a catalyst support for a fuel cell, it exhibits high catalytic activity and excellent oxidation resistance. As said high temperature heat processing temperature, 1500 degreeC or more is suitable, for example. This is because heat treatment at a high temperature of 1500 ° C. or higher controls the graphite crystal structure contained in the porous material and further improves the oxidation resistance of the resulting catalyst carrier. Examples of the solvent that substantially extracts at least a part of the fullerene include aromatic organic solvents.

BET specific surface area of the porous material used in the present invention is preferably a 350~1450m ² / g, more preferably 350~1300m ² / g.

  The catalyst carrier of the present invention is excellent in dispersibility of catalytically active components such as noble metals and is highly active and also excellent in oxidation resistance. The catalyst carrier of the present invention is particularly suitable for an electrode catalyst for a fuel cell.

  The catalyst carrier of the present invention is a fullerene-containing soot, or an extraction residue obtained by substantially extracting at least a part of fullerene from a fullerene-containing soot using a solvent, after activation treatment, high-temperature heat treatment, or after activation treatment It contains a porous substance obtained by high-temperature heat treatment.

  First, the fullerene-containing soot used in the present invention or an extraction residue obtained by substantially extracting at least a part of fullerene from the fullerene-containing soot using a solvent will be described. In the following description, “fullerene-containing soot or an extraction residue obtained by substantially extracting at least a part of fullerene from a fullerene-containing soot using a solvent” is simply abbreviated as “fullerene-containing soot”. There is.

As is well known, fullerene is a carbon molecule having a hollow shell-like structure closed by a network of five-membered rings and six-membered rings. For example, C ₆₀ , C ₇₀ , C ₇₆ , C ₈₀ , C ₈₄ , Mention may be made of C ₈₆ , C ₉₀ , C ₉₄ , C ₉₆ , C ₁₈₀ , C ₂₄₀ , C ₃₂₀ , C ₅₄₀ , or mixtures thereof. The fullerene-containing soot is not particularly limited as long as it is a soot that can be produced when producing fullerene. As a method for producing fullerene, for example, a method of evaporating a raw material by arc discharge using a graphite electrode (arc discharge method), a method of evaporating a raw material by passing a high current through a carbonaceous material (resistance heating method), an ultraviolet There are a method of irradiating a graphite with a laser (laser evaporation method), a method of incompletely burning a carbon-containing compound such as benzene (combustion method), etc., and any method can obtain soot containing fullerene. For the fullerene-containing soot, in addition to the above-mentioned fullerene, for example, a fullerene precursor that has not reached a closed ring structure such as fullerene, graphite or carbon having a graphite structure, amorphous carbon, amorphous carbon, carbon black Or a polycyclic aromatic hydrocarbon.

Examples of the fullerene-containing soot, be mentioned fullerene-containing soot containing fullerene-containing soot and the toluene soluble fullerenes containing C ₆₀ obtained by an arc discharge method or laser evaporation method at least 10% 3 wt% or more it can.

In the present invention, an extraction residue obtained by substantially extracting at least a part of fullerene from the fullerene-containing soot using a solvent can be used. An extraction residue obtained by substantially extracting at least a part of fullerene from a fullerene-containing soot using a solvent is a residue obtained by substantially extracting a fullerene component soluble in a solvent from the fullerene components contained in the fullerene-containing soot. Means a thing. For example, fullerene having 60 to 70 carbon atoms (such as C _{60 to} C ₇₀ ) is soluble in a solvent described later, and is extracted from the fullerene-containing soot with the solvent. An extraction residue obtained by substantially extracting at least a part of the fullerene from the fullerene-containing soot using a solvent includes a precursor of the fullerene, carbon having a graphite or a graphite structure, and amorphous carbon. , amorphous carbon, and carbon black, is considered to contain a like C ₇₀ or higher order fullerenes.

Examples of the solvent used when substantially extracting at least a part of fullerene from the fullerene-containing soot using a solvent include organic solvents such as aromatic hydrocarbons and aliphatic hydrocarbons. Examples thereof include aromatic organic solvents such as benzene, toluene, xylene, 1-methylnaphthalene, 1,2,4-trimethylbenzene, and tetralin, and among these, toluene is preferable. Using _toluene, can be extracted C _{60 -C 120} about fullerene.

  Examples of a method for obtaining an extraction residue by substantially extracting at least a part of fullerene from a fullerene-containing soot using a solvent include the following methods. First, a solvent having a mass of about 60 times is added to fullerene-containing soot to prepare a dispersion of fullerene-containing soot, and this dispersion is treated with ultrasonic waves at room temperature for 1 hour to be soluble in the solvent of fullerene-containing soot. The fullerene component and other solvent-soluble components are dissolved in the solvent. Next, the dispersion of the fullerene-containing soot is filtered, and the fullerene-containing soot is washed with a solvent until the filtrate is no longer colored, so that at least a part of the solvent-soluble fullerene and other solvent-soluble components are substantially removed. And the obtained extraction residue is vacuum-dried at about 60 ° C.

  Next, the fullerene-containing soot or the extraction residue obtained by substantially extracting at least a part of the fullerene using a solvent from the fullerene-containing soot is subjected to activation treatment, high-temperature heat treatment, or high-temperature heat treatment after activation treatment. The porous material obtained will be described.

  The “activation treatment” in the present invention is not particularly limited as long as it is a treatment for making the fullerene-containing soot porous, and increasing its specific surface area. For example, chemical activation treatment, gas activation treatment, less than 1500 ° C. A heat treatment at a temperature can be employed.

  The chemical activation treatment can be performed, for example, by mixing the fullerene-containing soot described above and an alkali metal compound as an activator and performing heat treatment. Examples of the alkali metal compound include alkali metal hydroxides such as potassium hydroxide and sodium hydroxide; alkali metal carbonates such as potassium carbonate and sodium carbonate; alkali metal sulfates such as potassium sulfate and sodium sulfate; And aqueous solutions and hydrates thereof. Preferred as the activator is a hydrate or concentrated aqueous solution of an alkali metal hydroxide such as potassium hydroxide or sodium hydroxide. Although the usage-amount of the alkali metal compound with respect to the said fullerene containing soot etc. is not specifically limited, For example, it is an alkali metal compound / fullerene containing soot etc. (mass ratio) = 0.3 or more and 4.0 or less. preferable.

  The heat treatment at the time of chemical activation is not particularly limited. For example, the heat treatment can be performed at 500 ° C. or higher and 900 ° C. or lower, and the heat treatment is performed in an inert gas atmosphere such as argon or nitrogen. Is also a preferred embodiment. In addition, when chemical activation is performed using an alkali metal hydroxide or the like, washing with an acid and / or water is performed, and an unreacted activator present in the fullerene-containing soot etc. or an alkali generated as a result of the reaction. It is a preferred embodiment to remove a metal compound (for example, potassium compound). Moreover, it is preferable that the carbonaceous material washed with an acid and / or water is vacuum-dried. This is because the acid and / or water remaining inside the fullerene-containing soot can be easily removed by vacuum drying.

  In the present invention, the fullerene-containing soot may be subjected to a gas activation treatment. The gas activation treatment is preferably performed, for example, by bringing the fullerene-containing soot described above into contact with an oxidizing gas at 750 ° C. or higher. The temperature of the gas activation treatment is preferably 800 ° C. or higher, more preferably 850 ° C. or higher, preferably 1100 ° C. or lower, more preferably 1050 ° C. or lower. Moreover, as said oxidizing gas, a carbon dioxide gas, water vapor | steam, oxygen, combustion exhaust gas, a mixture thereof, etc. can be used, for example.

  In the present invention, the fullerene-containing soot and the like described above can be made porous to a practical level simply by heat treatment at a temperature of less than 1500 ° C. (preferably 750 ° C. to 1500 ° C., more preferably 800 ° C. to 1400 ° C.). Porous material is obtained. The details of the mechanism for heat treatment of fullerene-containing soot and the like to make it porous are unknown, but part of fullerene contained in fullerene-containing soot etc. sublimates during the heat treatment, and the place where fullerene was present is hollow It is also considered that the fullerene-containing soot and the like become porous. The heat treatment of the fullerene-containing soot or the like at a temperature of less than 1500 ° C. is preferably performed in an inert atmosphere. For example, a container in which carbon that is easily oxidized is placed in an atmosphere of an inert gas atmosphere such as nitrogen or argon. It is preferable to carry out in a substantially inert atmosphere, for example, in a crucible made of carbon and firing.

  In the activation process of the present invention, a heat treatment at a temperature lower than 1500 ° C. and a chemical activation process or a gas activation process can be performed in a superimposed manner. For example, a heat treatment at a temperature of less than 1500 ° C. and a gas activation treatment using an oxidizing gas can be appropriately combined. Following the heat treatment at a temperature of less than 1500 ° C. in an inert gas atmosphere, an oxidizing gas can be used. The aspect which performs the gas activation process to be used, and the aspect which heat-processes at the temperature below 1500 degreeC following a gas activation process can be mentioned.

  In the present invention, it is also a preferred aspect to adjust the amount of surface functional groups of the porous material by heat-treating the porous material after washing or activation treatment at a temperature of less than 1500 ° C. in an inert gas atmosphere. As the heat treatment at a temperature of less than 1500 ° C. for adjusting the amount of functional groups on the surface of the porous material, an embodiment in which the porous material immediately after activation is heat-treated in an inert gas atmosphere; the porous material immediately after activation is treated with an acid and An embodiment in which heat treatment is performed in an inert gas atmosphere after washing with water; an embodiment in which a porous material immediately after activation is washed with an organic solvent, and then heat treatment is performed in an inert gas atmosphere; And / or an embodiment in which the substrate is washed with water and heat-treated in an inert gas atmosphere, and further washed with an organic solvent and heat-treated in an inert gas atmosphere. As said inert gas, argon, nitrogen, helium etc. can be used, for example. The heat treatment temperature for adjusting the surface functional group amount of the porous material is not particularly limited, but is preferably less than 1500 ° C, more preferably 1000 ° C or less, and preferably 400 ° C or more.

  The “high temperature heat treatment” in the present invention is to heat treat the fullerene-containing soot or the like, or a product obtained by activating the fullerene-containing soot, at a high temperature of 1500 ° C. or higher in a substantially inert atmosphere. Such high-temperature heat treatment is intended to adjust the graphite crystal structure contained in the porous material and further improve the oxidation resistance (durability) of the resulting catalyst carrier. However, as described above, fullerene-containing soot and the like are activated simply by heat treatment, and thus the high-temperature heat treatment may substantially double as activation treatment for fullerene-containing soot and the like. In addition, it is also a preferable aspect to perform activation processing of fullerene containing soot etc. and the said high temperature heat processing separately.

  The high temperature heat treatment temperature in this embodiment is not particularly limited, but is preferably 1500 ° C. or higher, more preferably 1600 ° C. or higher, preferably 2500 ° C. or lower, more preferably 2200 ° C. or lower. This is because if the high-temperature heat treatment temperature is too low, the development of the graphite crystal structure is low, and if the high-temperature heat treatment temperature is too high, the pores once developed may decrease and the specific surface area may be reduced. The high-temperature heat treatment (graphite crystal structure adjustment) is preferably performed in an inert atmosphere. For example, in an atmosphere of an inert gas such as nitrogen or argon, a oxidizable carbon is placed in a surrounding container or a crucible made of carbon. It is preferable to carry out in a substantially inert atmosphere, such as putting and baking. The high temperature heat treatment can also be performed under reduced pressure (in a vacuum), for example.

  Next, the porous material used in the present invention is not particularly limited as long as it is obtained by the production method described above, but preferably has the following characteristics.

Porous material for use in the present invention, BET specific surface area of 350 meters ² / g or more, more preferably be at 400 meters ² / g or more, 1450 m ² / g or less, more preferably 1300 m ² / g or less, more preferably It is desirable that it is 1000 m < ² > / g or less. The larger the specific surface area, the better the catalyst supportability. Therefore, by setting it to 350 m ² / g or more, the dispersion of the catalyst when used as a catalyst carrier is improved. On the other hand, by setting it as 1450 m < ² > / g or less, the fall of the oxidation resistance of the catalyst support obtained can be prevented.

  The catalyst carrier of the present invention is not particularly limited as long as it contains the above-described porous material. For example, the catalyst carrier of the present invention is substantially composed of the porous material described above, or in addition to the porous material described above. As long as the effect of the present invention is not substantially lowered, an embodiment containing conductive carbon black that has been used as a conventional catalyst carrier can be exemplified.

  The method of supporting the catalytically active component such as (noble) metal on the catalyst carrier of the present invention prepared as described above is not particularly limited. For example, the catalyst carrier is dispersed in a (noble) metal salt solution, A method of reducing the metal ions in the solution by adding a reducing agent and precipitating the metal on the catalyst carrier, or a solution of the (noble) metal salt in which the catalyst carrier is dispersed is heated and stirred to form a metal salt And the like, after being deposited on the catalyst support, filtration, washing, drying and the like are appropriately performed, and a reduction treatment with hydrogen gas or the like can be given. Examples of the (noble) metal that can be supported on the catalyst carrier of the present invention include platinum, rhenium, palladium, iridium, rhodium, ruthenium, osmium, gold, silver, and alloys thereof.

  Since the catalyst carrier of the present invention is excellent in the dispersibility of the catalytically active component, it is suitable for an electrode catalyst for a fuel cell that needs to efficiently form a three-phase interface reaction. In particular, it is suitable for an electrode catalyst of a polymer electrolyte fuel cell that is being put into practical use for consumer use.

  Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to the following examples, and all modifications and embodiments within the scope not departing from the gist of the present invention are described in the present invention. Included within the scope of the invention.

[Method for measuring BET specific surface area]
The BET specific surface area of the extraction residue and the porous material was measured using an ASAP-2400 nitrogen adsorption device manufactured by Micromeritics, and determined by the BET multipoint method.

[X-ray diffraction measurement]
X-ray diffraction measurement was performed under the following conditions.
X-ray diffraction measurement apparatus: X'Pert PRO type manufactured by Spectris X-ray source: Cu-Kα ray (wavelength 1.54 mm), output: 40 KV 40 mA, operation axis: θ / 2θ, measurement mode: Continuous, measurement range: 2θ = 5 to 80 °, capture width: 0.01 °, scanning speed: 5.0 ° / min.
The graphitization degree was analyzed based on the Gakushin method by adding standard silicon.

[Catalyst activity evaluation]
The catalytic activity was evaluated by the rotating electrode method, which was reported to be effective for the evaluation of solid polymer electrolyte fuel cell catalysts and had a good correlation with fuel cell performance (S.Lj.Gojkovic, SKZecevic and RF Savinell, “O ₂ Reduction on an Ink-Type Rotating Disk Electrode Using Pt Supported on High-Area Carbon”, J. Electrochem. Soc. 145, 3713 (1998)).

  2 g of a porous substance as a catalyst carrier was mixed with 45 g of a dinitrodiamine platinum nitric acid solution (platinum content: 4.5 mass%) manufactured by Tanaka Kikinzoku Co., Ltd. After stirring, 11 ml of ethanol was added as a reducing agent. This solution was refluxed for 6 hours with stirring, and platinum was supported on the porous material. Thereafter, the solution was filtered, washed and dried to obtain an electrode catalyst. The amount of platinum supported in the obtained catalyst was 33% by mass.

To 0.15 g of the obtained platinum-supported catalyst, 1.6 g of a 5% Nafion solution (manufactured by Aldrich) was added and dispersed by ultrasonic waves to prepare a catalyst paste. Next, 6 μl of the catalyst paste was applied to a rotating glassy carbon disk electrode (manufactured by Hokuto Denko, application area 0.196 cm ² ), and fixed by drying. The rotating electrode was immersed in a 0.1 M sulfuric acid aqueous solution saturated with oxygen, and the relationship between the oxygen reduction current and the electrode potential was measured while rotating at 1500 rpm using the silver / silver chloride electrode as a reference electrode.

[Evaluation of oxidation resistance by thermobalance]
Using a TG-DTA2000SP manufactured by Bruca AXS, the platinum-supported catalyst was heated to 350 ° C under a nitrogen stream of 100 ml / min, air reaching 100 ml / min was added, held for 1 hour, and weight loss was measured did.

Example 1
Using a rotary kiln, the temperature of a fullerene-containing soot (manufactured by Aldrich, product name Fullerene Soot as prodeced) was raised to 950 ° C. in a nitrogen atmosphere, and then maintained at 950 ° C., nitrogen / water vapor = 50/50 (volume ratio) Was kept for 15 minutes in the atmosphere to perform a gas activation treatment and cooled to obtain a porous material. The specific surface area of the obtained porous material was 1030 m ² / g. Table 1 shows the relationship between the oxygen reduction current and the electrode potential of a platinum-supported catalyst using the obtained porous material as a catalyst carrier.

The result of measuring X-ray diffraction of the fullerene-containing soot used as a raw material is shown in FIG. Peaks derived from graphite are observed in the vicinity of 27 °, 44 °, and 55 °, peaks considered to be derived from fullerene C ₆₀ in the vicinity of 11 °, 17 °, and 21 °, and amorphous and amorphous shapes. An increase in plateau-like baseline, which is thought to be derived from carbon, was observed.

( Reference Example 1 )
About 60 times the mass of toluene was added to the fullerene-containing soot used in Example 1 to prepare a dispersion of fullerene-containing soot, and this dispersion was treated with ultrasound at room temperature for 1 hour. Filter, wash with toluene until the filtrate is no longer colored, and vacuum-dry the filtrate for about 5 hours at 60 ° C., and extract at least a part of the fullerene using a solvent from the fullerene-containing soot. Thus obtained extraction residue was obtained. The specific surface area of the extraction residue was 180 m ² / g. The result of measuring the X-ray diffraction of the extracted residue is shown in FIG. From FIG. 2, it is recognized that peaks near 11 °, 17 ° and 21 ° considered to be derived from fullerene C ₆₀ almost disappeared. From this result, it can be seen that the extracted residue obtained is that C ₆₀ and C ₇₀ are substantially extracted as at least a part of the fullerene from the fullerene-containing soot.

The extraction residue was subjected to activation treatment in the same manner as in Example 1 using a rotary kiln to obtain a porous material. The porous material was further subjected to high-temperature heat treatment in a static high-temperature furnace at 1500 ° C. or higher under an argon atmosphere for 5 hours or longer. The specific surface area of this high-temperature heat-treated product (porous material) was 560 m ² / g. 3 is an X-ray diffraction result by the Gakushin method of the porous material after the high-temperature heat treatment, and FIG. 4 is a partially enlarged view of 24 ° to 28 ° of FIG. is there. 3 and 4 show that a new graphite peak is observed in the porous material after the high-temperature heat treatment on the low angle side of the graphite peak around 2θ = 26.5 degrees derived from the raw material, although the crystallinity is low. It was. Table 1 shows the relationship between the oxygen reduction current and the electrode potential of a platinum-supported catalyst using the obtained porous material as a catalyst carrier. FIG. 5 shows an oxidation weight loss curve by a thermobalance.

(Example 3)
The fullerene-containing soot used in Example 1 was subjected to high-temperature heat treatment at 1500 ° C. or higher under an argon atmosphere for 5 hours or longer in a static high-temperature furnace to obtain a porous material. The specific surface area of this porous material was 410 m ² / g. Table 1 shows the relationship between the oxygen reduction current and the electrode potential of a platinum-supported catalyst using the obtained porous material as a catalyst carrier. FIG. 5 shows an oxidation weight loss curve by a thermobalance.

( Reference Example 2 )
The fullerene-containing soot used in Example 1 was heat-treated at 1000 ° C. to 1500 ° C. for 5 hours or more in an argon atmosphere in a static high temperature furnace to obtain a porous material. The specific surface area of this porous material was 510 m ² / g. Table 1 shows the relationship between the oxygen reduction current and the electrode potential of the platinum-supported catalyst using the obtained catalyst carrier. FIG. 5 shows an oxidation weight loss curve by a thermobalance.

(Comparative Example 1)
In place of the porous material used in the examples, a conductive carbon black marketed as an electrode catalyst for a fuel cell was used, and the condition was 5 hours or more at 1500 ° C. or higher in an argon atmosphere in a stationary high temperature furnace. The porous material was obtained by high-temperature heat treatment. The specific surface area of the obtained porous material was 590 m ² / g. Table 1 shows the relationship between the oxygen reduction current and the electrode potential of a platinum-supported catalyst using the obtained porous material as a catalyst carrier. FIG. 5 shows an oxidation weight loss curve by a thermobalance.

(Comparative Example 2)
An electrode catalyst was produced in the same manner as in Example 1 using the toluene extraction residue produced in Reference Example 1 as a catalyst carrier. Table 1 shows the relationship between the oxygen reduction current and the electrode potential of a platinum-supported catalyst using the obtained porous material as a catalyst carrier.

  From Table 1, it can be seen that when the catalyst carrier of the present invention is used, the electrode potential is high and the catalytic activity is high in the electrode. On the other hand, when the catalyst carriers of Comparative Examples 1 and 2 were used, the electrode potential was lowered. FIG. 5 also shows that when the catalyst carrier of the present invention is used, the weight reduction rate is low and the oxidation resistance is excellent. In particular, it can be seen that the oxidation resistance of Example 3 in which the fullerene-containing soot is heat-treated at a high temperature is very good.

  The catalyst carrier of the present invention has high dispersibility of (noble) metal catalyst, high activity and good oxidation resistance, and is particularly suitable for an electrode catalyst of a polymer electrolyte fuel cell.

2 is an X-ray diffraction pattern of fullerene-containing soot used in the present invention. It is an X-ray diffraction pattern of an extraction residue obtained by substantially extracting at least a part of fullerene from a fullerene-containing soot used in the present invention using a solvent. 2 is an X-ray diffraction pattern of a porous material after high-temperature heat treatment. It is the elements on larger scale in 24 degrees-28 degrees of FIG. It is a graph which shows the weight reduction at the time of heat processing of an electrode catalyst.

Claims (4)

  A catalyst carrier comprising a porous material obtained by activating a fullerene-containing soot at a high temperature heat treatment of 1500 ° C. or higher, or a high temperature heat treatment at 1500 ° C. or higher after the activation treatment. The catalyst carrier according to claim 1, wherein the porous material has a BET specific surface area of 350 to 1450 m ² / g. The catalyst carrier according to claim 2 , wherein the porous material has a BET specific surface area of 350 to 1300 m ² / g. The catalyst carrier according to any one of claims 1 to 3 , which is used for an electrode catalyst of a fuel cell.