JP2018174078A - Carbon material for catalyst carrier of solid polymer fuel cell and manufacturing method thereof, and catalyst carrier for solid polymer fuel cell arranged by use of carbon material for catalyst carrier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carbon material for a catalyst carrier, which is low in volume density, and suitable for manufacturing a catalyst of a solid polymer fuel cell superior in such characteristics as required in use as a fuel battery; a method for manufacturing the carbon material; and a catalyst carrier for a solid polymer fuel cell, which is arranged by use of the carbon material.SOLUTION: Disclosed are a carbon material for a catalyst carrier of a solid polymer fuel cell and a method for manufacturing the same. The carbon material is a porous carbon material which satisfies all of the following requirements: (1) the volume density is 0.05 g/mL or more and less than 0.14 g/mL; (2) BET specific surface area determined by BET analysis of a nitrogen gas adsorption isotherm is 400-1500 m/g; and (3) a cumulative pore volume Vof a pore size of 2-10 nm determined by analysis of the nitrogen gas adsorption isotherm by Dollimore-Heal method is 0.4-1.5 mL/g.SELECTED DRAWING: None

Description

  The present invention relates to a carbon material for a catalyst support of a polymer electrolyte fuel cell, a method for producing the same, and a catalyst support for a polymer electrolyte fuel cell using the carbon material for a catalyst support, and more particularly to a solid polymer fuel. The present invention relates to a carbon material for a catalyst carrier that is useful as a catalyst carrier for preparing a battery catalyst and a method for producing the same.

  In recent years, polymer electrolyte fuel cells that can operate at a low temperature of 100 ° C. or less have attracted attention, and are being developed and put into practical use as driving power sources for vehicles and stationary power generators. A general polymer electrolyte fuel cell has a membrane electrode assembly (MEA) in which a catalyst layer serving as an anode and a cathode is disposed on both sides of a proton conductive electrolyte membrane, respectively. The basic structure (unit cell) is composed of a gas diffusion layer disposed outside the catalyst layer with the membrane electrode assembly interposed therebetween, and a separator disposed outside the gas diffusion layer. , By stacking as many unit cells as necessary to achieve the required output.

In the unit cell of such a polymer electrolyte fuel cell, from the gas flow path of the separator disposed on the anode side and the cathode side, an oxidizing gas such as oxygen or air is provided on the cathode side, Fuel such as hydrogen is supplied to the anode side, and the supplied oxidizing gas and fuel (these are sometimes referred to as “reactive gases”) are supplied to the catalyst layer through the gas diffusion layers, respectively. Work is taken out by utilizing an energy difference (potential difference) between a chemical reaction occurring in the anode catalyst layer and a chemical reaction occurring in the cathode catalyst layer. For example, when hydrogen gas is used as the fuel and oxygen gas is used as the oxidizing gas, a chemical reaction that occurs in the catalyst layer of the anode [oxidation reaction: H ₂ → 2H ⁺ + 2e ⁻ (E ₀ = 0V)] And an energy difference (potential difference) between the chemical reaction occurring in the cathode catalyst layer [reduction reaction: O ₂ + 4H ⁺ + 4e ⁻ → 2H ₂ O (E ₀ = 1.23 V)].

  Here, for a catalyst that forms a catalyst layer as described above to cause a chemical reaction, a porous carbon material is usually used as a catalyst carrier from the viewpoint of electron conductivity, chemical stability, and electrochemical stability. As the catalyst metal, Pt or a Pt alloy that can be used in a strongly acidic environment and exhibits high reaction activity for both oxidation reaction and reduction reaction is mainly used. For catalytic metals, the above oxidation reaction and reduction reaction generally occur on the catalytic metal. In order to increase the utilization rate of the catalytic metal, it is necessary to increase the specific surface area per mass. Have a particle size of several nanometers.

  And about the catalyst support | carrier which carry | supports such a catalyst metal particle | grain, in order to raise the carrying | supporting capability as a support | carrier, That is, the site for adsorbing and carrying | supporting the said catalyst metal particle of about several nanometers is increased. Therefore, it is necessary to be a porous carbon material having a large specific surface area, and the volume of the mesopores having a pore diameter of 2 to 50 nm so as to support the catalytic metal particles in a highly dispersed state as much as possible. That is, it is required to be a porous carbon material having a large mesopore volume, and at the same time, when a catalyst layer to be an anode and a cathode is formed, the reaction gas supplied into the catalyst layer is diffused without resistance, In addition, in order to discharge water generated in the catalyst layer (generated water) without delay, it is necessary to form fine pores suitable for diffusion of reaction gas and discharge of generated water in the catalyst layer.

  Therefore, conventionally, as a porous carbon material having a relatively large specific surface area and mesopore volume, and at the same time having a tree-like structure with three-dimensionally developed branches, for example, CABOT Vulcan XC-72, Lion EC600JD made by the company and EC300 made by Lion Corporation are used. In addition, attempts have been made to develop a porous carbon material having a more suitable specific surface area and mesopore volume as a catalyst support carbon material and having a more suitable dendritic structure. As a starting material, there is a dendritic carbon nanostructure produced using a metal acetylide such as silver acetylide having a three-dimensionally branched three-dimensional tree structure as an intermediate, and maintaining this three-dimensional tree structure. Some proposals have been made.

For example, Patent Document 1 discloses a step of preparing a solution containing a metal or a metal salt, a step of blowing acetylene gas into the solution to generate a dendritic carbon nanostructure made of metal acetylide, and the carbon nanostructure. A step of heating the body at 60 to 80 ° C. to produce a metal-encapsulated dendritic carbon nanostructure in which metal is encapsulated in the dendritic carbon nanostructure, and 160 of the metal-encapsulated dendritic carbon nanostructure. Heating to 200 ° C. to eject metal to produce a dendritic carbon mesoporous structure, heating the carbon mesoporous structure to 1600-2200 ° C. under a reduced pressure atmosphere or an inert gas atmosphere, A porous carbon material prepared by a production method comprising: a pore diameter of 1 to 20 nm and an integrated pore volume of 0.2 to 1.5 cc / g determined by analyzing a nitrogen adsorption isotherm by a Dollimore-Heal method Have Rutotomoni, a BET specific surface area 200~1300m ² / g, low reduction rate of the current amount for a long period, the catalyst for the possible preparation of a catalyst carrier for a solid polymer fuel cell having excellent durability Carbon materials have been proposed.

Moreover, in patent document 2, the acetylene production | generation process which blows in acetylene gas in the ammoniacal aqueous solution containing a metal or a metal salt, and produces | generates a metal acetylide, the said metal acetylide is heated at the temperature of 60-80 degreeC, and a metal particle A first heat treatment step for creating an inclusion intermediate, and heating the metal particle inclusion intermediate at a temperature of 120 to 200 ° C. to eject metal particles from the metal particle inclusion intermediate to obtain a carbon material intermediate A second heat treatment step, a washing treatment step of bringing the carbon material intermediate into contact with hot concentrated sulfuric acid to purify the carbon material intermediate, and further cleaning the carbon material intermediate at 1000 to 2100 ° C. A porous carbon material prepared by a manufacturing method comprising a third heat treatment step for obtaining a support carbon material by heat treatment, having a predetermined hydrogen content, and a BET ratio table Product 600~1500m ² / g, and the range of the peak intensity of Raman range of peak intensity of the spectrum obtained from D- band 1200~1400cm ^-1 (l _D) and G- band 1500~1700cm ^-1 (l _G) Carbon material having a relative strength ratio (l _D / l _G ) of 1.0 to 2.0 and capable of preparing a catalyst for a polymer electrolyte fuel cell capable of exhibiting high battery performance under high humidification conditions Has been proposed.

Furthermore, in Patent Document 3, an acetylide generating step of generating acetylene gas by blowing acetylene gas into an ammoniacal aqueous solution containing a metal or a metal salt, and heating the metal acetylide at a temperature of 40 to 80 ° C. to form metal particles A first heat treatment step for producing an inclusion intermediate, the metal particle inclusion intermediate is compacted, and the resulting molded article is heated to 400 ° C. or higher at a temperature rising rate of 100 ° C. or more per minute. A second heat treatment step of ejecting metal particles from the particle inclusion intermediate to obtain a carbon material intermediate; and contacting the carbon material intermediate with hot concentrated nitric acid or hot concentrated sulfuric acid to clean the carbon material intermediate And a third heat treatment step for obtaining a carrier carbon material by heat-treating the cleaned carbon material intermediate in a vacuum or in an inert gas atmosphere at 1400 to 2100 ° C. A porous carbon material prepared by the manufacturing process comprising, the specific surface area S _A of the mesopores of pore diameters 2~50nm obtained by analyzing the nitrogen adsorption isotherm of adsorption process in Dollimore-Heal method 600 1600 m ² / g, and the peak intensity (l _{G ′} ) in the range of G′-band 2650-2700 cm ⁻¹ and the peak intensity (l _G ) in the range of 1550-1650 cm ⁻¹ in the Raman spectrum. The relative intensity ratio (l _{G ′} / l _G ) is 0.8 to 2.2, and the specific pore area S _{2-10 of the} mesopores having a pore diameter of 2 nm or more and less than 10 nm in the mesopores is 400 to 1100 m. ² / g, the specific pore volume V _2-10 is 0.4 to 1.6 cc / g, and the specific pore area S _{10− of the} mesopores having a pore diameter of 10 nm or more and 50 nm or less in the mesopores. ₅₀ is 20-150 m ² / g, specific pore volume V _2-10 is 0.4-1.6 cc / g, and the nitrogen adsorption isotherm of the adsorption process is Horva The specific pore area S ₂ of pores having a pore diameter of less than 2 nm determined by analysis by th-Kawazoe method is 250 to 550 m ² / g, which is excellent against potential fluctuations while maintaining high power generation performance. There has been proposed a carbon material for a catalyst support capable of preparing a solid polymer fuel cell catalyst capable of exhibiting durability.

Furthermore, in Patent Document 4, a porous carbon material having a dendritic carbon nanostructure prepared through a self-decomposing explosion reaction using metal acetylide as an intermediate [trade name: ESCARBON, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.] (Registered trademark) -MCND] as a raw material, and after performing a graphitization treatment, a carbon material for a catalyst support obtained by further performing an oxidation treatment using hydrogen peroxide, nitric acid, a submerged plasma apparatus, etc. The oxygen content O _ICP is 0.1 to 3.0% by mass, the oxygen remaining amount O _{1200 ° C.} remaining after heat treatment at 1200 ° C. in an inert gas (or vacuum) atmosphere is 0.1 to 1.5% by mass, BET specific surface area is 300-1500 m ² / g, G-band half-value width ΔG detected in the range of 1550-1650 cm ⁻¹ of Raman spectrum is 30-70 cm ⁻¹ , and in an inert gas (or vacuum) atmosphere Remains after heat treatment at 1200 ° C Containing residual amounts H _{1200 ° C.} is that 0.005 to 0.080 mass%, excellent durability against repeated load fluctuations such starting and stopping, also has excellent power generation performance under operating conditions at the time of low humidification A carbon material for a catalyst carrier capable of preparing a catalyst for a polymer electrolyte fuel cell has been proposed.

WO 2014/129597 A1 Publication WO 2015/088025 A1 Publication WO 2015/141810 A1 Publication WO 2016/133132 A1 Publication

The carbon materials for catalyst supports described in the above Patent Documents 1 to 4 have a relatively large specific surface area and mesopore volume, and are excellent in durability. Although it has excellent large current characteristics, which are important for drawing out a large output when used as a battery, the inventors of the present application have continued further detailed investigation, and while maintaining durability, the large current It has been found that there is room for further improvement in enhancing the characteristics.
In order to enhance this large current characteristic, as described above, a relatively large specific surface area and mesopore volume are required for supporting the catalyst metal platinum sufficiently and in a highly dispersed state on the catalyst support. In addition to the above, it is important that the diffusibility of the reaction gas is excellent. The cause of the overvoltage generated at the time of a large current is considered to be a governing factor due to the migration resistance (diffusion resistance) of the substance involved in the positive electrode reaction. The specific substances involved in the movement resistance are electrons, protons, oxygen, and water vapor that is generated, but the electrons move through the carrier carbon material, exhibit ohmic resistance behavior, and increase resistance due to large currents. It is not considered to give. Protons move through the proton conductive resin, and as long as the wetness is constant, they exhibit ohmic resistance like electrons, and there is no special overvoltage increase at high currents. For this reason, it is generally accepted that the main cause of overvoltage at high current is the diffusion of oxygen and water vapor. In order to improve the diffusion of oxygen and water vapor, based on the viewpoint of improving the diffusibility of oxygen and water vapor in the porous carbon pores, it may correlate with the bulk density of the carbon material for the catalyst support. I came up with the idea.

That is, the bulk density in the porous carbon material represents the degree of development of the pore structure, but when the micro to meso pore volume is equivalent, the macro pore volume, ie, the tree, is reduced by making this as low as possible. It has been speculated that the porous carbon material will have a developed structure, thereby improving the diffusibility of the reaction gas and, as a result, the idea that high current characteristics can be enhanced.
In view of this point, the inventors of the present application have studied that Patent Document 3 discloses that the thickness of the branch of a three-dimensional dendritic structure is increased by increasing the acetylene concentration in the process of producing metal acetylide as a raw material of the porous carbon material. Although it is disclosed about the porous carbon which can make ΔG small without impairing the DBP oil absorption and the BET specific surface area which show the degree of the dendritic network by appropriately increasing the length and the length of the dendritic network. As for the conventional carbon materials for the catalyst support, an oxidizing acid solution containing (concentrated) nitric acid or hot concentrated sulfuric acid is used in the step of dissolving and removing the silver particles in the process of obtaining the carbon material. However, when silver is removed by such an oxidizing acid, carbon oxidation occurs not a little. When the carbon is oxidized, functional groups such as hydroxyl groups and carboxyl groups are imparted to the surface of the particles. Such a surface functional group causes a dehydration condensation reaction in the course of a heat treatment performed at about 2000 ° C., which is subsequently performed, thereby causing sintering of the particles. Thus, in the conventional carbon material for a catalyst support, It turned out that there was a problem that the bulk density could not be lowered significantly.

  Then, the inventors of the present application examined the above-mentioned problems of the prior art in more detail, and have been treated with an acid solution so far, focusing on the fact that silver is easily vaporized at high temperature under reduced pressure. By radically changing the silver removal (cleaning process) and heating at a predetermined temperature in a reduced-pressure atmosphere, the silver removal process with an oxidizing acid is not performed, so that functional groups on the particle surface can be removed. Addition and subsequent sintering of particles during high-temperature treatment can be prevented, the bulk density is lower than conventional carbon materials for catalyst supports, gas diffusibility is good, and the power generation characteristics of conventional carbon materials for catalyst supports The present invention has been completed by finding out that there is also an advantage that it is better than that using the.

The present invention has been invented based on the above-described findings, and the object of the present invention is that the bulk density is lower than that of conventional carbon materials for catalyst supports, a dendritic structure is developed, and gas diffusibility is achieved. In producing a polymer electrolyte fuel cell catalyst that excels in power generation characteristics and characteristics required for use as a fuel cell (specific surface area, mesopore volume, durability, etc.) An object is to provide a suitable carbon material for a catalyst support.
Furthermore, another object of the present invention is to provide a method for producing a carbon material for a catalyst carrier that is useful for producing such a catalyst for a polymer electrolyte fuel cell.

That is, the present invention is as follows.
[1] A carbon material for a catalyst carrier of a polymer electrolyte fuel cell, which is a porous carbon material and satisfies the following (1), (2) and (3) simultaneously.
(1) The bulk density is 0.05 g / mL or more and less than 0.14 g / mL.
(2) The BET specific surface area calculated | required by the BET analysis of a nitrogen gas adsorption isotherm is 400-1500 m < ² > / g.
(3) The integrated pore volume V _2-10 having a pore diameter of 2 to 10 nm determined by analysis using a Dollimore-Heal method of nitrogen gas adsorption isotherm is 0.4 to 1.5 mL / g.
[2] half-width ΔG of G- bands detected in the range of 1550～1650Cm ^-1 Raman spectroscopy spectrum, the polymer electrolyte fuel according to characterized in that it is a 50 to 70 cm ^-1 (1) Carbon material for battery catalyst support.
[3] The carbon material for a catalyst support of a polymer electrolyte fuel cell according to [1] or [2], wherein the V _2-10 is 0.5 to 1.0 mL / g.
[4] The catalyst carrier of a polymer electrolyte fuel cell according to any one of [1] to [3], wherein the mode diameter of mesopores determined in nitrogen gas adsorption measurement is more than 2 nm and less than 9 nm Carbon material for use.
[5] The carbon material for a catalyst support of a polymer electrolyte fuel cell according to any one of [1] to [4], wherein the bulk density is 0.05 g / mL or more and 0.10 g / mL or less.
[6] The catalyst support for a polymer electrolyte fuel cell according to any one of [1] to [5], wherein the rod-like body or the annular body has a three-dimensional tree-like structure in which the rod-like body or the annular body is branched three-dimensionally Carbon material.
[7] A catalyst support for a polymer electrolyte fuel cell using the carbon material for a catalyst support according to any one of [1] to [6].

[8] A method for producing a carbon material for a catalyst support of a polymer electrolyte fuel cell according to any one of [1] to [6],
A silver acetylide production step of synthesizing silver acetylide by blowing acetylene gas into a reaction solution consisting of an aqueous silver nitrate solution, a decomposition step of obtaining a decomposition product by subjecting the silver acetylide to an autolytic explosion reaction, and the decomposition product A cleaning process for obtaining a carbon material intermediate from which silver has been removed by heat treatment at a temperature of 1400 to 1800 ° C. in a reduced-pressure atmosphere, and the carbon material intermediate in a vacuum or an inert gas atmosphere at 1800 to 2200 ° C. And a heat treatment step of obtaining a carbon material for a catalyst carrier by performing a heat treatment at a temperature of 5 to 10. A method for producing a carbon material for a catalyst carrier of a polymer electrolyte fuel cell, comprising:

ADVANTAGE OF THE INVENTION According to this invention, the carbon material for catalyst supports of a high specific surface area with a low bulk density and excellent gas diffusibility and high oxidation resistance can be provided. Furthermore, high catalytic activity can be imparted by using these carbon materials for catalyst carriers as catalyst carriers for fuel cells.
Further, according to the production method of the present invention, it is useful for producing a catalyst for a polymer electrolyte fuel cell, and has a high specific surface area with high bulk density, low gas density, excellent gas diffusibility, and high oxidation resistance. A method for manufacturing the material can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

<Method for producing carbon material for catalyst support>
First, the manufacturing method of the carbon material for catalyst carriers which concerns on one Embodiment of this invention is demonstrated. The method for producing a carbon material for a catalyst carrier according to the present embodiment includes a silver acetylide production step for obtaining silver acetylide, and decomposition by heating the silver acetylide to obtain a decomposition product composed of a composite material of silver and carbon. A cleaning step of treating the decomposition product comprising the composite material in a reduced pressure atmosphere at a temperature of 1400 ° C. to 1800 ° C. to remove silver from the composite material to obtain a carbon material intermediate; A heat treatment step of further obtaining a porous carbon material for a catalyst carrier by further heat-treating the carbon material intermediate from which silver has been removed. Hereinafter, each step will be described in detail.

(Silver acetylide production process)
The silver acetylide production step is not particularly limited as long as it is a known method. For example, a method of producing silver acetylide by bringing a silver nitrate aqueous solution and acetylene molecules into contact with each other as described in Patent Document 1 can be used.

  The contact method of the acetylene gas is not particularly limited, and examples thereof include a method of passing the acetylene gas through the silver nitrate aqueous solution, and more specifically, a method of blowing the acetylene gas into the silver nitrate aqueous solution.

  Further, when the silver nitrate aqueous solution and the acetylene gas are brought into contact with each other, ultrasonic waves can be irradiated to the silver nitrate aqueous solution. Thereby, the effect that dissolution and dispersion | distribution in the silver nitrate aqueous solution of acetylene gas are accelerated | stimulated is acquired.

  Moreover, it is preferable to stir the silver nitrate aqueous solution at the time of contact between the silver nitrate aqueous solution and the acetylene gas. As a result, the contact frequency of the contact between the acetylene gas and the aqueous silver nitrate solution increases, and as a result, silver acetylide is efficiently generated. Stirring may be performed using a general stirring blade, or may be performed using a stirring bar such as a magnetic stirrer.

  Thus, silver acetylide can be obtained as a bulky precipitate of white crystals.

(Disassembly process)
Next, the obtained silver acetylide is decomposed by heating to obtain a decomposition product made of a composite material. By heating the silver acetylide, the silver acetylide explodes at the nanoscale and phase-separates into silver and carbon. At this time, the silver forms nano-sized particles or is gasified by the reaction heat to form a surface portion. Erupts. Carbon has a highly aromatic structure because three acetylene-based compounds such as acetylene molecules easily gather to form a benzene ring. Further, since silver forms nanoparticles, the carbon phase from which silver has been removed becomes a porous structure.

  The heating of silver acetylide can be performed as follows, for example. The obtained silver acetylide precipitate is heated in a reduced-pressure atmosphere at, for example, 40 ° C. or more and 100 ° C. or less (this will be referred to as “first heat treatment”), thereby remaining in the silver acetylide. Thus, the solvent in the reaction solution can be removed, the thermal energy of the explosion can be prevented from being spent on the sensible heat of the phase transition of the solvent to the gas phase, and the decomposition of the silver acetylide can be made efficient. At this temperature, silver acetylide does not decompose.

  Next, the silver acetylide from which the solvent has been removed is heated at, for example, 150 ° C. or more and 400 ° C. or less (this will be referred to as “second heat treatment”). By heating the silver acetylide to such a relatively high temperature, the silver acetylide explodes on the nanoscale and decomposes, and silver and carbon each form a nanostructure. Thereby, the decomposition product which consists of a composite material containing silver and carbon is obtained. Note that the basic structure of the carbon phase portion of the composite material is mainly composed of several layers of graphene by forming a polycyclic aromatic with an acetylene compound as described above. In the composite material, since silver forms nanoscale particles in the explosion process, a carbon material from which silver particles have been removed can be obtained as a carbon material having a large specific surface area and a high porosity. .

[Cleaning process (silver removal process)]
Next, the obtained decomposition product made of the composite material is subjected to heat treatment at a temperature of 1400 ° C. or higher and 1800 ° C. or lower in a reduced-pressure atmosphere (this is referred to as “third heat treatment”). ) Evaporate and remove at least a portion of the metal from the composite material.

  By performing such third heat treatment, silver is efficiently and sufficiently removed from the composite material. That is, since the vapor pressure of silver is relatively high at a temperature in the above range, the silver exposed on the carbon surface is easily vaporized and removed from the composite material. On the other hand, within the above temperature range, the carbon material, which is the main component of the composite material, undergoes a structural change due to heat, specifically, an increase in graphene size due to bonding between graphenes, development of a laminated structure of graphene, etc. As a result of structural change and deformation of the structure, silver encapsulated in the composite material is exposed on the surface of the composite material. Thereby, silver which was included in the composite material before the third heat treatment can also be vaporized and removed from the composite material. In addition, since silver is removed, the same material after silver removal becomes a carbon material consisting essentially of carbon, and in the present invention, this is referred to as a carbon material intermediate.

  By adopting this step, it is possible to prevent the problem that the metal cannot be sufficiently removed, which has been partially confirmed in the conventional cleaning process using nitric acid or hot concentrated sulfuric acid.

  In addition, as described above, in the conventional cleaning treatment with nitric acid, hot concentrated sulfuric acid, etc., functional groups such as hydroxyl groups and carboxyl groups are added to the carbon particle surface by oxidizing carbon, thereby In the subsequent heat treatment step described later, the bulk density of the carbon material for the catalyst support tends to increase due to the sintering of the particles caused when the added functional group causes a dehydration condensation reaction. However, it turned out that this can be prevented by changing to this process.

  The element component derived from silver acetylide remaining in the carbon material intermediate obtained through this step can be analyzed by a known measurement method. For example, inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma emission spectroscopy (ICP-AES), atomic absorption spectrometry (AAS) and the like can be mentioned. Here, the amount of silver derived from silver acetylide remaining in the carbon material intermediate obtained through this step is, for example, preferably less than 1000 ppm, more preferably less than 500 ppm, and still more preferably not detected. . If a large amount of silver remains, the remaining silver may adversely affect the application characteristics depending on the use of the carbon material for the catalyst support. Further, silver remaining in the subsequent heat treatment step may volatilize and contaminate or damage an apparatus such as a heating furnace.

  Moreover, the temperature in this process is 1400 degreeC or more and 1800 degrees C or less as mentioned above. When the temperature in this step is less than the lower limit, even if the degree of vacuum is improved, the vapor pressure of silver is not sufficiently high, and the silver removal efficiency is not sufficient. On the other hand, when the temperature in this step exceeds the upper limit, graphitization is promoted in the heat treatment step described later by the graphitization catalytic action of silver present in the carbon material intermediate after the treatment, and the bulk density increases. There is a fear.

  The time in this step is not particularly limited, but is, for example, 10 minutes to 20 hours, preferably 30 minutes to 10 hours. Thereby, while being able to remove a metal fully, unintentional excessive carbonization and crystallization are prevented, and the quality of the porous carbon material finally obtained can be managed more easily.

  The pressure in this step is not particularly limited, but in this step, for example, the treatment is performed in a reduced pressure atmosphere of 0.1 Pa to 10,000 Pa, preferably 1 Pa to 5000 Pa, more preferably 1 Pa to 1000 Pa. Is done. The metal can be efficiently removed by keeping the atmospheric pressure low.

(Heat treatment process)
Next, the carbon material intermediate from which silver has been removed is heat-treated to obtain a porous carbon material for a catalyst carrier (this will be referred to as “fourth heat treatment”). Crystals of the porous carbon material can be developed by heat treatment performed in this step, and the crystallinity can be adjusted and controlled by temperature. For example, when used as a catalyst support for an electrode of a polymer electrolyte fuel cell, the porous carbon material has a relatively high temperature, for example, about 80 ° C., a strong acidity of pH 1 or less, and 1.3 V vs SHE. Although exposed to a high potential environment, the carbon in the porous carbon material is easily oxidized and consumed under such an environment. Therefore, when using the porous carbon material as a catalyst carrier, it is important to increase crystallinity in this step.

  By the way, the pores and specific surface area in the porous carbon material are factors that greatly affect the amount of the catalyst supported when used as a catalyst carrier. Therefore, the porous carbon material has many pores and the specific surface area. Is generally preferred. However, generally, when a porous carbon material is heat-treated, crystals develop, but the pores are crushed and the specific surface area of the material is reduced.

  From such a viewpoint, the temperature of the heat treatment in this step is preferably 1800 ° C. or higher and 2200 ° C. or lower. Thereby, while reducing the specific surface area, the crystallinity of the porous carbon material can be sufficiently enhanced without increasing the bulk density.

The heat treatment in this step is not particularly limited, but can be performed, for example, in a reduced pressure atmosphere or an inert gas atmosphere, and preferably in an inert gas atmosphere. Although it does not specifically limit as an inert gas, For example, nitrogen, argon, etc. can be used.
In addition, this process can be performed using a general heating furnace. Moreover, this process may be continued from the above-mentioned silver removal process.

  In the method for producing a porous carbon material according to the present embodiment described above, by adopting the removal step as described above, the silver particles can be efficiently and sufficiently removed from the composite material, and the obtained carbon for the catalyst support is obtained. It is possible to reduce the bulk density of the material.

<Carbon material for catalyst support>
Next, the porous carbon material for a catalyst carrier obtained by the present invention will be described.
The carbon material for a catalyst carrier produced by the above method is formed by ejecting silver using a bulky precipitate of silver acetylide as a raw material. Therefore, the carbon material for the catalyst support is a porous body having many ejection holes (mesopores). The presence of such mesopores has a relatively large specific surface area and can carry, for example, a catalyst or the like on the surface.

  In addition, the microscopic structure of the carbon material for the catalyst support may vary depending on the type of metal acetylide, that is, the type of metal used to form the metal acetylide.

  When the carbon material for a catalyst support is derived from silver acetylide, it has a dendritic carbon mesoporous structure having a three-dimensional structure in which rod-like bodies or cyclic bodies containing carbon are branched three-dimensionally. More specifically, this carbon mesoporous structure has a so-called dendrite-like three-dimensional structure in which rod-like bodies or annular bodies extend three-dimensionally and combine with each other to form a network. Yes.

  Further, the carbon mesoporous structure is generally composed of a skin made of graphene and carbon grains such as a plurality of graphene parcels contained therein due to a manufacturing method and the like. Here, the “graphene” is an arrangement of carbon atoms in a hexagonal network, and corresponds to a single layer of graphite.

  Since the carbon mesoporous structure has a dendritic portion as described above, the carbon mesoporous structure itself has a high specific surface area. Therefore, any gas such as hydrogen can be sufficiently occluded and can sufficiently function as a gas molecule occlusion body. Further, it can sufficiently function as a catalyst support.

  Here, it is generally said that when the bulk density is 0.10 g / mL or less in the porous carbon material, it may be difficult to ensure both the specific surface area and the carbon wall strength. Since the carbon material is composed of a graphene skin as described above and carbon grains such as a plurality of graphene parcels contained therein, even if the bulk density is less than 0.10 g / mL, the carbon wall It has been confirmed from a cross-sectional photograph of a polymer electrolyte fuel cell catalyst layer using the porous carbon material. However, even with the carbon material for a catalyst carrier of the present invention, if the bulk density is less than 0.05 g / mL, it may be difficult to maintain the strength of the carbon wall. On the other hand, if the bulk density is 0.14 g / mL or more, it can be considered that the particles are sintered in the production process of the carbon material for the catalyst support, and the gap between the dendritic structures is reduced. For example, when used as a member of a polymer electrolyte fuel cell, gas diffusibility is lowered.

As for the catalyst carrier carbon material for the present invention, the above (2) as, BET specific surface area as determined by BET analysis of nitrogen sorption isotherms 400~1500m ² / g, preferably 500 meters ² / g or more 1400m ² / g or less, and when the BET specific surface area is 400 m ² / g or more, preferably 500 m ² / g or more, the catalyst metal particles of several nm are in a well dispersed state, that is, The catalyst metal particles are supported in such a state that the distance between the catalyst metal particles is maintained at a certain value or more and the particles can exist alone. On the other hand, when the BET specific surface area is less than 400 m ² / g, the distance between the catalyst particles may be shortened, and it may be difficult to uniformly support the catalyst metal fine particles at a high density. The area is reduced, and the fuel cell characteristics are greatly reduced. On the other hand, if it exceeds 1500 m ² / g, the edge portion in the porous carbon material increases, so that there is a risk that durability is likely to be lowered with a substantial decrease in crystallinity.

Further, such a carbon material for a catalyst carrier of the present invention has an integrated pore volume V having a pore diameter of 2 to 10 nm determined by analysis using a Dollimore-Heal method of a nitrogen gas adsorption isotherm as described in (3) above. _2-10 should be 0.4 to 1.5 mL / g, preferably 0.5 to 1.0 mL / g. By having such a pore diameter of 2 to 10 nm, the catalyst metal fine particles that are usually prepared to have a diameter of several nm are dispersed in the pores in a highly dispersed state, which preferably contributes from the viewpoint of catalyst utilization. When the pore volume V _2-10 is less than 0.4 mL / g, the average pore size is small because the volume is small relative to the pore area. When platinum fine particles, which are catalytic metals, are supported in the pores, the gap between the pores and the platinum fine particles becomes small, so that there is a risk that gas diffusion will decrease and the large current characteristics will deteriorate. On the other hand, when V _2-10 exceeds 1.5 mL / g, the skeleton as the carbon material for the support becomes thin, and the oxidation consumption resistance decreases and the catalyst layer for preparing the catalyst layer The skeleton of the carbon material for the carrier is easily destroyed by stirring necessary for preparing the ink liquid, and there is a possibility that the characteristics derived from the shape cannot be exhibited.

  The most frequent diameter of the pore distribution of the mesopores derived from the carrier (in the present invention, simply referred to as “mesopore mode (straight) diameter”) is preferably more than 2 nm and less than 9 nm, more preferably. Is 2.1-5 nm or less. Since the general particle size of the catalyst particles used in the polymer electrolyte fuel cell is about 2 nm, the mesopores on which the catalyst particles are supported are preferably larger than 2 nm. On the other hand, when the mode diameter of the mesopores is increased to 9 nm or more, pores that are excessively larger than the catalyst particles exist, and the presence of unnecessary spaces causes a decrease in catalyst support efficiency. Invite.

In addition, the carbon material for the catalyst carrier of the present invention is detected in the range of 1550 to 1650 cm ⁻¹ of the Raman spectrum from the viewpoint of improving the crystallinity and improving the durability in the environment where the fuel cell is used. - half width ΔG band is preferably 50 to 70 cm ^-1, more preferably in the range of 50~65cm ^-1. This ΔG is said to represent the spread of the carbon network surface of the carbon material, and if ΔG is less than 50 cm ⁻¹ , the carbon network surface is too widened to reduce the edge amount of the carbon network surface forming the pore wall, There is a tendency that the supporting characteristics of the catalytic metal fine particles on the pore wall tend to be lowered, and conversely, if it exceeds 70 cm ⁻¹ , the carbon network surface becomes narrow, and the edge amount of the carbon network surface that is easily oxidized and consumed increases. Tend to decrease.

  As described above, the carbon material for a catalyst carrier of the present invention is preferably composed of a dendritic carbon nanostructure having a three-dimensional dendritic structure in which rod-like bodies or annular bodies are three-dimensionally branched as a catalyst carrier. In addition to the same or better BET specific surface area and durability as compared with the conventional dendritic carbon nanostructure of this type, as described above, the bulk density is low, thereby excellent gas diffusibility, Because it has a high specific surface area with high oxidation resistance, the reaction gas is diffused without resistance in the catalyst layer prepared using this carbon material as a catalyst support, and the water (product water) generated in this catalyst layer is delayed. It is possible to obtain a solid polymer fuel cell that has excellent mesopores that are suitable for discharge, and that is less likely to reduce the utilization rate of the catalytic metal, and that has excellent durability as a fuel cell. it can.

  Hereinafter, the carbon material for a catalyst carrier of the present invention will be specifically described with reference to examples. In addition, the Example shown below is only an example of this invention, Comprising: This invention is not limited to the following example.

1. Production of carbon material for catalyst support <Example 1>
(I-1) Silver acetylide production step After preparing a 1.9% by mass ammonia aqueous solution containing silver nitrate at a concentration of 15.6% by mass in a flask and removing residual oxygen with an inert gas such as argon or dry nitrogen, While stirring the solution and applying vibration by immersing the ultrasonic vibrator in the liquid, acetylene gas was sprayed on the 150 mL solution at a flow rate of 25 mL / min for about 4 minutes. This produced a solid of silver acetylide in the solution and began to precipitate. Next, the precipitate was filtered with a membrane filter, and at the time of filtration, the precipitate was washed with methanol, and a slight amount of methanol was added to impregnate the precipitate with methanol.

(I-2) Decomposition step of silver acetylide 1 g of the precipitate impregnated with methanol was placed in a test tube, and this was kept in a vacuum dryer at 30 to 40 ° C. for 1 hour to remove methanol. (First heat treatment), the mixture was rapidly heated to 160 ° C. to 200 ° C. as it was, and heated for 20 minutes (second heat treatment). Here, a nano-scale explosion reaction occurred in the test tube, and the encapsulated silver was ejected, and a large number of ejection holes were formed on the surface and inside. Thereby, the decomposition product which consists of a composite material containing silver and carbon as a silver inclusion nanostructure was obtained.

(I-3) Cleaning step (i-2) 25 g of the composite material containing silver and carbon obtained in the decomposition step of silver acetylide is weighed and placed in a graphite crucible, and heated to 3000 ° C. in an argon atmosphere. In a possible Tamman furnace, the pressure was reduced to 0.5 Pa after vacuum substitution with argon gas, and the temperature was increased to 1400 ° C. at 15 ° C./min. And after reaching predetermined temperature, the said temperature was maintained for 10 hours, the removal of silver was performed, and the purified carbon material intermediate body from which silver was removed was obtained (3rd heat processing).

(I-4) Heat treatment step The cleaned carbon material intermediate obtained in the cleaning step (i-3) was heated to 2100 ° C at 15 ° C / min under argon flow. Then, after reaching the predetermined temperature, the temperature was maintained for 2 hours to perform heat treatment (fourth heat treatment), and the porous carbon material for catalyst support according to Example 1 was obtained. In addition, as a graphite material for the crucible, a graphite crucible in which the density of the molded product does not increase was selected by extruding a low-density aggregate material having a large graphite particle diameter.
<Example 2>
A carbon material for a catalyst support was obtained in the same procedure as in Example 1 except that the maintenance temperature in the heat treatment step (fourth heat treatment) after silver removal was 2000 ° C.

<Example 3>
A carbon material for a catalyst support was obtained in the same procedure as in Example 1 except that the maintenance temperature in the heat treatment step (fourth heat treatment) after silver removal was 1900 ° C.

<Example 4>
A carbon material for a catalyst support was obtained in the same procedure as in Example 1 except that the maintenance temperature in the heat treatment step (fourth heat treatment) after silver removal was 1800 ° C.

<Example 5>
A carbon material for a catalyst support was obtained in the same procedure as in Example 1 except that the maintenance temperature in the cleaning step (silver removal step, third heat treatment) was 1600 ° C.

<Example 6>
Example except that the maintenance temperature of the cleaning step (silver removal step, third heat treatment) was 1600 ° C., and the maintenance temperature of the heat treatment step (fourth heat treatment) after silver removal was 1800 ° C. A carbon material for a catalyst support was obtained in the same procedure as in 1.

<Example 7>
A carbon material for a catalyst support was obtained in the same procedure as in Example 1 except that the maintenance temperature in the heat treatment step (fourth heat treatment) after silver removal was 2200 ° C.

<Comparative Example 1>
(Ii-1) Acid removal step 1
Using 20 g of a composite material (decomposition product) containing silver and carbon obtained by performing the above-described (i-2) silver acetylide decomposition step in Example 1, this was immersed in 1500 g of 30% by mass concentrated nitric acid. And washed at 60 ° C. for 24 hours. Subsequently, the composite material and concentrated nitric acid were separated using a centrifuge. In order to remove nitric acid adhering to the composite material, the separated composite material was dispersed again in pure water, and the composite material (solid) was separated from the liquid by a centrifuge. Nitric acid was removed by performing this washing operation twice. Next, moisture was removed by treatment in air at 140 ° C. for 2 hours, and then heat treatment was performed at 1100 ° C. for 2 hours under argon flow.

(Ii-2) Acid removal step 2
8 g of the composite material containing silver and carbon obtained in the acid removal step 1 of (ii-1) above was immersed in 150 g of 30% by mass concentrated nitric acid and washed at 60 ° C. for 24 hours. Subsequently, the composite material and concentrated nitric acid were separated using a centrifuge. In order to remove nitric acid adhering to the composite material, the separated composite material was dispersed again in pure water, and the composite material (solid) was separated from the liquid by a centrifuge. Nitric acid was removed by performing this washing operation twice. Next, the composite material was treated in air at 140 ° C. for 2 hours to remove moisture and dried, and then heat-treated at 1400 ° C. for 2 hours under argon flow.

(Ii-3) Heat treatment step 6 g of the composite material obtained in the above (ii-2) acid removal step 2 was heated to 2100 ° C at 15 ° C / min under argon flow. Then, after reaching the predetermined temperature, the temperature was maintained for 2 hours to perform heat treatment (fourth heat treatment), and the porous carbon material for catalyst support according to Comparative Example 1 was obtained.

<Comparative example 2>
A carbon material for a catalyst carrier was obtained in the same procedure as in Comparative Example 1 except that the maintenance temperature in the heat treatment step (fourth heat treatment) was 1800 ° C.

<Comparative Example 3>
A carbon material for a catalyst support was obtained in the same procedure as in Example 1 except that the maintenance temperature in the heat treatment step (fourth heat treatment) after silver removal was 1500 ° C.

<Comparative example 4>
A carbon material for a catalyst support was obtained in the same procedure as in Example 1 except that the maintenance temperature in the heat treatment step (fourth heat treatment) after silver removal was 1400 ° C.

<Comparative Example 5>
Example except that the maintenance temperature of the cleaning step (silver removal step, third heat treatment) was 1600 ° C., and the maintenance temperature of the heat treatment step (fourth heat treatment) after silver removal was 1500 ° C. A carbon material for a catalyst support was obtained in the same procedure as in 1.

<Comparative Example 6>
Example except that the maintenance temperature of the cleaning step (silver removal step, third heat treatment) was 1600 ° C., and the maintenance temperature of the heat treatment step (fourth heat treatment) after silver removal was 1300 ° C. A carbon material for a catalyst support was obtained in the same procedure as in 1.

<Comparative Example 7>
A carbon material for a catalyst support was obtained in the same procedure as in Example 1 except that the maintenance temperature in the heat treatment step (fourth heat treatment) after silver removal was 2300 ° C.

<Comparative Example 8>
A carbon material for a catalyst support was obtained in the same procedure as in Example 1 except that the maintenance temperature of the heat treatment step (fourth heat treatment) after silver removal was 2500 ° C.

<Comparative Example 9>
When the maintenance temperature of the cleaning step (silver removal step, third heat treatment) was 1300 ° C., the determination of the amount of residual silver contained in the cleaned carbon intermediate was rejected. Was not processed.

<Comparative Example 10>
When the maintenance temperature of the cleaning step (silver removal step, third heat treatment) was set to 1100 ° C., the determination of the amount of residual silver contained in the cleaned carbon intermediate was rejected. Was not processed.

<Comparative Example 11>
5 g of ketjen black EC600JD (manufactured by Lion Corporation) was heated to 2100 ° C. at 15 ° C./min under an argon stream. Then, after reaching the predetermined temperature, the temperature was maintained for 2 hours and heat treatment was performed (corresponding to the fourth heat treatment) to obtain a carbon material for a catalyst carrier.

<Comparative Example 12>
A carbon material for a catalyst support was obtained in the same procedure as in Comparative Example 11 except that the maintenance temperature of the heat treatment (corresponding to the fourth heat treatment) was 2000 ° C.

<Comparative Example 13>
A carbon material for a catalyst carrier was obtained in the same procedure as in Comparative Example 11 except that the maintenance temperature of the heat treatment (corresponding to the fourth heat treatment) was 1900 ° C.

2. Evaluation (i) Measurement of BET specific surface area, integrated pore volume V _{2-10 with} pore diameter of 2 to 10 nm, and mode diameter About 30 mg of each of the carbon materials for the catalyst support of each Example and Comparative Example were weighed at 150 ° C. After vacuum drying, the specific surface area was measured by a gas adsorption method using nitrogen gas using an automatic specific surface area measuring apparatus (QUADRASORB evo, manufactured by Cantachrome Instruments Japan Ltd.), and the specific surface area was determined based on the BET analytical formula. . The adsorption isotherm of the adsorption process was analyzed and calculated by the Dollimore-Heal method (DH method). The integrated pore volume V _2-10 (mL / g) and pore mode diameter (nm) of mesopores having a pore diameter of 2 to 10 nm were calculated by an analysis program built in the apparatus. The evaluation results are shown in Table 1.

(Ii) G-band half-value width ΔG (cm ⁻¹ ) detected in the range of 1550 to 1650 cm ⁻¹ of the Raman spectrum.
After measuring about 3 mg of the catalyst support carbon material prepared in each of the examples and comparative examples as a sample, it was set in a laser Raman spectrophotometer (NRS-3100 model manufactured by JASCO Corporation), and an excitation laser: 532 nm, laser power: 10 mW (sample irradiation power: 1.1 mW), microscopic arrangement: Backscattering, slit: 100 μm × 100 μm, objective lens: × 100 times, spot diameter: 1 μm, exposure time: 30 sec, observation wave number: 2000 to 300 cm ⁻¹ and the number of integrations: Measured under 6 measurement conditions, so as to obtain a half-value width ΔG (cm ⁻¹ ) of so-called graphite G-band appearing in the vicinity of 1580 cm ⁻¹ from the obtained 6 spectra, The average value was taken as the measured value.

(Iii) Bulk density About 300 mg of each of the carbon materials for the catalyst support of each Example and Comparative Example was weighed and tapped 150 times using a tap denser (KYT-5000 manufactured by Seishin Enterprise), and the bulk density was measured. The evaluation results are shown in Table 1.
(IV) Measurement of remaining amount of silver The remaining amount of silver remaining in the cleaned carbon material intermediate after the cleaning step of each example and comparative example or the carbon material intermediate after acid treatment 2 is inductively coupled plasma emission. Obtained by spectroscopic analysis (ICP-AES). In this evaluation, those that failed were heat treatment step (fourth heat treatment) because the remaining silver volatilized in the subsequent heat treatment step (fourth heat treatment) and could damage the furnace body. Cannot be implemented.
[Acceptance rank]
○: Silver remaining amount below detection limit to 1000 ppm or less [failed rank]
X: Silver remaining amount exceeds 1000 ppm

<Catalyst preparation, catalyst layer production, MEA production, fuel cell assembly, and battery performance (durability) evaluation>
Next, using each of the carbon materials for the catalyst carrier prepared as described above, a catalyst for a polymer electrolyte fuel cell carrying a catalyst metal is prepared as follows, and the obtained catalyst is used. The catalyst layer ink liquid is prepared, and then the catalyst layer is formed using the catalyst layer ink liquid. Further, the membrane electrode assembly (MEA: Membrane Electrode Assembly) is manufactured using the formed catalyst layer. The produced MEA was incorporated into a fuel cell, and a power generation test was performed using a fuel cell measurement device. Hereinafter, preparation of each member and cell evaluation by a power generation test will be described in detail.

(1) Preparation of solid polymer fuel cell catalyst (platinum-supported carbon material) Each of the catalyst support carbon materials prepared above was dispersed in distilled water, and formaldehyde was added to this dispersion to set the temperature at 40 ° C. After being set in a water bath and the temperature of the dispersion reached 40 ° C., which was the same as that in the bath, an aqueous dinitrodiamine Pt complex nitric acid solution was slowly poured into the dispersion with stirring. Thereafter, stirring was continued for about 2 hours, followed by filtration, and washing of the obtained solid was performed. The solid material thus obtained was vacuum-dried at 90 ° C., pulverized in a mortar, and then heat-treated at 200 ° C. for 1 hour in an argon atmosphere containing 5% by volume of hydrogen to produce a platinum catalyst particle-supporting carbon material. did. The platinum loading amount of the platinum-supporting carbon material is adjusted to 25% by mass with respect to the total mass of the carbon material for the catalyst support and the platinum particles, and inductively coupled plasma emission spectroscopy (ICP-AES: Inductively It was confirmed by measurement by Coupled Plasma-Atomic Emission Spectrometry.

(2) Preparation of catalyst layer The platinum-supported carbon material (Pt catalyst) prepared as described above was used, and Nafion (registered trademark: Nafion; persulfonic acid ion exchange resin) manufactured by Dupont was used as the electrolyte resin. Using these Pt catalyst and Nafion in an Ar atmosphere, the mass of Nafion solids is 1.0 times that of the platinum catalyst particle-supporting carbon material, and 0.5 times that of non-porous carbon. After blending and lightly stirring, the Pt catalyst is crushed with ultrasonic waves, and ethanol is further added to adjust the total solid concentration of the Pt catalyst and electrolyte resin to 1.0% by mass. A catalyst layer ink liquid in which a Pt catalyst and an electrolyte resin were mixed was prepared.

Ethanol was further added to each of the catalyst layer ink liquids having a solid content concentration of 1.0% by mass thus prepared to prepare a catalyst layer ink solution for spray coating having a platinum concentration of 0.5% by mass, and a platinum catalyst. The spray conditions were adjusted so that the mass per unit area of the layer (hereinafter referred to as “platinum weight”) was 0.1 mg / cm ^2, and the above-mentioned catalyst layer ink for spray coating was placed on the Teflon (registered trademark) sheet. After spraying, a drying process was performed in argon at 120 ° C. for 60 minutes to prepare a catalyst layer.

(3) Production of MEA Using the catalyst layer produced as described above, a MEA (membrane electrode assembly) was produced by the following method.
A square electrolyte membrane having a side of 6 cm was cut out from a Nafion membrane (NR211 manufactured by Dupont). In addition, each of the anode and cathode catalyst layers coated on the Teflon (registered trademark) sheet was cut into a square shape having a side of 2.5 cm with a cutter knife.
Between each of the anode and cathode catalyst layers cut out in this way, each catalyst layer is in contact with each other with the center portion of the electrolyte membrane interposed therebetween, and the electrolyte membrane is sandwiched so that there is no deviation from each other. After pressing at 10 cm / cm ² for 10 minutes and then cooling to room temperature, only the Teflon (registered trademark) sheet was carefully peeled off for both the anode and cathode, and the catalyst layer in which the anode and cathode catalyst layers were fixed to the electrolyte membrane-electrolyte membrane A zygote was prepared.

Next, as a gas diffusion layer, a pair of square carbon paper having a side of 2.5 cm is cut out from carbon paper (35BC manufactured by SGL Carbon Co.), and the catalyst layers of the anode and the cathode are sandwiched between these carbon papers. So that there is no deviation and the catalyst layer-electrolyte membrane assembly was sandwiched and pressed at 120 ° C. and 50 kg / cm ² for 10 minutes to prepare an MEA.
In addition, about the estimated amount of each component of the catalyst metal component, carbon material, and electrolyte material in each produced MEA, the mass of the Teflon (registered trademark) sheet with the catalyst layer before pressing and the Teflon (registered trademark) peeled off after pressing The mass of the catalyst layer fixed on the Nafion membrane (electrolyte membrane) was determined from the difference from the mass of the sheet, and calculated from the mass ratio of the composition of the catalyst layer.

(4) Evaluation of power generation performance of fuel cells MEAs produced using the carbon materials for the catalyst carriers according to the examples and comparative examples are incorporated into the cells, set in the fuel cell measuring device, and fueled by the following procedure. The battery performance was evaluated.
Air is adjusted as an oxidizing gas on the cathode side, and pure hydrogen is used as a reaction gas on the anode side, and the pressure is adjusted by a back pressure valve provided downstream of the cell so that the utilization rates are 40% and 70%, respectively. The back pressure was 0.1 MPa. The cell temperature was set to 80 ° C., and the oxidizing gas and reaction gas to be supplied were bubbled with distilled water kept at 60 ° C. in a humidifier for both the cathode and anode, and in a low humidified state. The power generation was evaluated.

Under these conditions, the reaction gas was supplied to the cell, and the load was gradually increased. The voltage across the cell terminals at a current density of 1000 mA / cm ² was recorded as the output voltage, and the fuel cell performance was evaluated. The evaluation was performed based on the following criteria of pass rank ○ and fail rank x. The results are shown in Table 1.
[Acceptance rank]
A: The output voltage at 1000 mA / cm ² is 0.65 V or more.
[Failed rank]
×: what output voltage at 1000 mA / cm ² is less than 0.65V.

[Evaluation of durability]
In the above cell, while maintaining the anode as it is and flowing argon gas under the same humidification condition as above to the cathode, the cell voltage is set to 1.0 V and held for 4 seconds and the cell voltage is set to 1.3 V and held for 4 seconds. The operation (repeat operation of rectangular wave voltage fluctuation) is repeated as one cycle, and after 200 cycles of this square wave voltage fluctuation operation, the durability is improved in the same manner as the evaluation of the large current characteristics described above. It investigated and evaluated by the criteria of the following pass rank (circle) and the failure rank x. The results are shown in Table 1.
[Acceptance rank]
A: The output voltage at 1000 mA / cm ² is 0.65 V or more.
[Failed rank]
×: what output voltage at 1000 mA / cm ² is less than 0.65V.

Claims (8)

A carbon material for a catalyst carrier of a polymer electrolyte fuel cell, which is a porous carbon material and satisfies the following (1), (2) and (3) simultaneously.
(1) The bulk density is 0.05 g / mL or more and less than 0.14 g / mL.
(2) The BET specific surface area calculated | required by the BET analysis of a nitrogen gas adsorption isotherm is 400-1500 m < ² > / g.
(3) The integrated pore volume V _2-10 having a pore diameter of 2 to 10 nm determined by analysis using a Dollimore-Heal method of nitrogen gas adsorption isotherm is 0.4 to 1.5 mL / g. Half width ΔG of G- bands detected in the range of 1550～1650Cm ^-1 Raman spectroscopy spectrum, the polymer electrolyte fuel cell according to claim 1, characterized in that a 50 to 70 cm ^-1 catalyst Carbon material for support. 3. The carbon material for a catalyst support of a polymer electrolyte fuel cell according to claim 1, wherein the V _2-10 is 0.5 to 1.0 mL / g.   The carbon material for a catalyst support of a polymer electrolyte fuel cell according to any one of claims 1 to 3, wherein the mode diameter of mesopores determined in nitrogen gas adsorption measurement is more than 2 nm and less than 9 nm.   5. The carbon material for a catalyst support of a polymer electrolyte fuel cell according to claim 1, wherein the bulk density is 0.05 g / mL or more and 0.10 g / mL or less.   6. The carbon material for a catalyst support of a polymer electrolyte fuel cell according to claim 1, wherein the rod-like body or the annular body has a three-dimensional tree-like structure in which the rod-like body or the annular body is branched three-dimensionally.   A catalyst support for a polymer electrolyte fuel cell using the carbon material for a catalyst support according to any one of claims 1 to 6. A method for producing a carbon material for a catalyst support of a polymer electrolyte fuel cell according to any one of claims 1 to 6,
A silver acetylide production step of synthesizing silver acetylide by blowing acetylene gas into a reaction solution consisting of an aqueous silver nitrate solution, a decomposition step of obtaining a decomposition product by subjecting the silver acetylide to an autolytic explosion reaction, and the decomposition product A cleaning process for obtaining a carbon material intermediate from which silver has been removed by heat treatment at a temperature of 1400 to 1800 ° C. in a reduced-pressure atmosphere, and the carbon material intermediate in a vacuum or an inert gas atmosphere at 1800 to 2200 ° C. And a heat treatment step of obtaining a carbon material for a catalyst carrier by performing a heat treatment at a temperature of 5 to 10. A method for producing a carbon material for a catalyst carrier of a polymer electrolyte fuel cell, comprising: