WO2023218790A1 - Catalyst carrier for fuel cells, catalyst for fuel cells, electrode catalyst layer, and fuel cell - Google Patents

Catalyst carrier for fuel cells, catalyst for fuel cells, electrode catalyst layer, and fuel cell Download PDF

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Publication number
WO2023218790A1
WO2023218790A1 PCT/JP2023/012971 JP2023012971W WO2023218790A1 WO 2023218790 A1 WO2023218790 A1 WO 2023218790A1 JP 2023012971 W JP2023012971 W JP 2023012971W WO 2023218790 A1 WO2023218790 A1 WO 2023218790A1
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fuel cell
carbon black
less
catalyst layer
electrode catalyst
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PCT/JP2023/012971
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French (fr)
Japanese (ja)
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哲哉 伊藤
祐作 原田
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デンカ株式会社
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
    • B01J23/42—Platinum
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/90—Selection of catalytic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/90—Selection of catalytic material
    • H01M4/92—Metals of platinum group
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/96—Carbon-based electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

Definitions

  • the present invention relates to a fuel cell catalyst carrier, a fuel cell catalyst, an electrode catalyst layer, and a fuel cell.
  • fuel cells having a cell structure of separator/gas diffusion layer/electrode catalyst layer/electrolyte membrane/electrode catalyst layer/gas diffusion layer/separator have been used as polymer electrolyte fuel cells.
  • the electrode catalyst layer for example, a layer in which carbon black carrying metal particles such as platinum particles is dispersed in an electrolyte is used.
  • a method for efficiently dispersing carbon black in an electrode catalyst layer for example, a first step of mixing catalyst-supported carbon black, an ion exchange resin, and a solvent and externally shearing the mixture with an external shearer, and an internal shearer
  • a method for producing a catalyst paste for a fuel cell which includes a second step of performing internal shearing (liquid-liquid shearing), and a third step of performing external shearing again.
  • the metal particles in the electrode catalyst layer have high catalytic activity per unit mass (reaction efficiency of the electrode catalyst layer).
  • the present invention relates to, for example, the following ⁇ 1> to ⁇ 8>.
  • ⁇ 1> A fuel cell catalyst carrier made of carbon black, The specific surface area is 170 m 2 /g or more and 400 m 2 /g or less, The ratio (S 2 /S 1 ) of the peak area (S 1 ) of the m/z 57 peak to the peak area (S 2 ) of the m/z 128 peak detected by temperature programmed desorption gas analysis is 2.00. is less than Support for catalysts for fuel cells.
  • ⁇ 2> As described in ⁇ 1>, when a 3% by mass slurry is prepared using N-methyl-2-pyrrolidone as a dispersion medium, the slurry viscosity at 25°C and a shear rate of 10 s -1 is 400 mPa s or more and 1500 mPa s or less.
  • catalyst carrier for fuel cells ⁇ 3> The fuel cell catalyst carrier according to ⁇ 1> or ⁇ 2>, which has a hydrochloric acid absorption amount of 39 mL/5 g or more.
  • ⁇ 4> The fuel cell catalyst carrier according to any one of ⁇ 1> to ⁇ 3>, which has a DBP absorption amount of 200 mL/100 g or more and 400 mL/100 g or less.
  • a fuel cell catalyst comprising at least one metal particle selected from the group consisting of platinum particles and platinum alloy particles supported on the fuel cell catalyst carrier according to any one of ⁇ 1> to ⁇ 4>.
  • ⁇ 7> A fuel cell comprising the electrode catalyst layer according to ⁇ 6>.
  • ⁇ 8> comprising a first separator, a first gas diffusion layer, an anode electrode catalyst layer, an electrolyte membrane, a cathode electrode catalyst layer, a second gas diffusion layer, and a second separator, A fuel cell, wherein at least one of the anode electrode catalyst layer and the cathode electrode catalyst layer is the electrode catalyst layer according to ⁇ 6>.
  • a carrier for a fuel cell catalyst is provided that can realize a fuel cell catalyst that can achieve both high dispersibility and high reaction efficiency. Further, according to the present invention, a fuel cell catalyst is provided that is capable of achieving both high dispersibility and high reaction efficiency. Furthermore, according to the present invention, an electrode catalyst layer and a fuel cell containing the above fuel cell catalyst are provided.
  • FIG. 2 is a diagram showing a chart of m/z 57 and m/z 128 of carbon black used in Example 1, detected by temperature-programmed desorption gas analysis.
  • a numerical range indicated using “ ⁇ ” means a range from “more than” the number on the left side to “less than” the number on the right side.
  • a to B means greater than or equal to A and less than or equal to B.
  • the fuel cell catalyst carrier of this embodiment is made of carbon black, and is a carrier that forms a fuel cell catalyst by supporting metal particles, which will be described later.
  • the fuel cell catalyst carrier (hereinafter also simply referred to as carbon black) of the present embodiment has a specific surface area of 170 m 2 /g or more and 400 m 2 /g or less.
  • the reaction efficiency can be determined by comparing the level of voltage at the same current value in the current potential curve in fuel cell evaluation, and it can be said that the higher the voltage, the higher the reaction efficiency.
  • the specific surface area is 180 m 2 /g or more, 190 m 2 /g or more, 200 m 2 /g or more, 210 m 2 /g or more, 220 m 2 /g or more, or 230 m 2 /g or more.
  • the catalyst paste which is a mixture of a fuel cell catalyst, an electrolyte, and a solvent, tends to become non-uniform, and in the electrode catalyst layer obtained by coating the catalyst paste, the fuel cell catalyst tends to form agglomerated particles. Agglomerated particles in the electrode catalyst layer cause protrusions and may damage the electrolyte membrane-electrode assembly (MEA). Further, when the fuel cell catalyst aggregates in the electrode catalyst layer, the contact area between the gas and the metal particles becomes smaller, and the reaction efficiency decreases.
  • MEA electrolyte membrane-electrode assembly
  • the specific surface area is 400 m 2 /g or less, a uniform catalyst paste is easily obtained, an electrode catalyst layer with few aggregated particles is easily obtained, and long-term reliability and reaction efficiency are improved. From the viewpoint of achieving the above effects more significantly, the specific surface area may be 395 m 2 /g or less, or 390 m 2 /g or less.
  • the specific surface area is, for example, 170 to 400 m 2 /g, 170 to 395 m 2 /g, 170 to 390 m 2 /g, 180 to 400 m 2 /g, 180 to 395 m 2 /g, 180 to 390 m 2 /g, 190 ⁇ 400m 2 /g, 190 ⁇ 395m 2 /g, 190 ⁇ 390m 2 /g, 200 ⁇ 400m 2 /g, 200 ⁇ 395m 2 /g, 200 ⁇ 390m 2 /g, 210 ⁇ 400m 2 /g, 210 ⁇ 395m 2 /g, 210-390m 2 /g, 220-400m 2 /g, 220-395m 2 /g, 220-390m 2 /g, 230-400m 2 /g, 230-395m 2 /g or 230-390m 2 /g.
  • the ratio (S 2 /S 1 ) is less than 2.00.
  • the ratio (S 2 /S 1 ) indicates the ratio of organic components present on the surface of the carbon black, for example, the ratio of polycyclic aromatic hydrocarbons to aliphatic hydrocarbons.
  • m/z is a symbol that means the value on the horizontal axis of a mass spectrum.
  • the number to the right of m/z is the value (dimensionless quantity) obtained by dividing the mass of the target ion by the unified atomic mass unit and further dividing by the number of charges on the ion.
  • the peak position in the mass spectrum is indicated together with z.
  • the ratio (S 2 /S 1 ) can be determined by evolved gas mass spectrometry (EGA-MS). Specifically, carbon black was set in a gas chromatograph mass spectrometer equipped with a pyrolysis device, held at 50°C for 5 minutes in an atmospheric pressure He flow, and then heated to 800°C at a rate of 80°C/min. do. Perform mass spectrometry of the components desorbed by increasing the temperature under the following conditions, and calculate the ratio of the peak area (S 1 ) of the peak at m/z 57 to the peak area (S 2 ) of the peak at m/z 128. Then, the ratio (S 2 /S 1 ) is calculated.
  • EVA-MS evolved gas mass spectrometry
  • the peak area refers to the peak area of a component (component corresponding to m/z 57 or m/z 128) detected by desorption from carbon black due to temperature elevation in the temperature programmed desorption gas analysis method.
  • the present inventors found that in carbon black having a high specific surface area, the surface properties analyzed by temperature-programmed desorption gas analysis are determined by the number of aggregated particles in the electrode catalyst layer. was found to have a significant influence on That is, the carbon black of this embodiment has a ratio (S 2 /S 1 ) of less than 2.00, so that it can achieve a sufficiently low number of aggregated particles for practical use while having a high specific surface area.
  • the detected peak at m/z 128 is a peak derived from polycyclic aromatic hydrocarbons typified by naphthalene, and the peak at m/z 57 is a peak derived from aliphatic hydrocarbons. That is, a small ratio (S 2 /S 1 ) means that the proportion of polycyclic aromatic hydrocarbons present on the carbon black surface is small.
  • the ratio (S 2 /S 1 ) by setting the ratio (S 2 /S 1 ) to be less than 2.00, even carbon black with a developed structure and a high specific surface area is difficult to aggregate in the electrode catalyst layer and is not formed into aggregated particles. The resulting decrease in reaction efficiency and reliability can be suppressed. In addition, a uniform electrode catalyst layer is easily obtained, local variations in catalyst efficiency are suppressed, and a fuel cell with a high output voltage and long life is easily obtained.
  • the ratio (S 2 /S 1 ) is less than 2.00 in order to sufficiently reduce the number of aggregated particles in the electrode catalyst layer. This is desirable.
  • the ratio (S 2 /S 1 ) is less than 1.80, less than 1.60, less than 1.40, less than 1.20, less than 1.00, and 0. It may be less than .80, less than 0.60 or less than 0.50.
  • the lower limit of the ratio (S 2 /S 1 ) is not particularly limited, but from the viewpoint of excellent productivity, the ratio (S 2 /S 1 ) should be 0.05 or more, 0.10 or more, or 0.20 or more. It's fine. That is, the ratio (S 2 /S 1 ) is, for example, 0.05 or more and less than 2.00, 0.05 or more and less than 1.80, 0.05 or more and less than 1.60, 0.05 or more and less than 1.40, and 0. .05 or more and less than 1.20, 0.05 or more and less than 1.00, 0.05 or more and less than 0.80, 0.05 or more and less than 0.60, 0.05 or more and less than 0.50, 0.10 or more2.
  • 0.10 or more and less than 1.80 0.10 or more and less than 1.60, 0.10 or more and less than 1.40, 0.10 or more and less than 1.20, 0.10 or more and less than 1.00, 0. 10 or more and less than 0.80, 0.10 or more and less than 0.60, 0.10 or more and less than 0.50, 0.20 or more and less than 2.00, 0.20 or more and less than 1.80, 0.20 or more and less than 1.60 less than 0.20 or more, less than 1.40, 0.20 or more and less than 1.20, 0.20 or more and less than 1.00, 0.20 or more and less than 0.80, 0.20 or more and less than 0.60, or 0.20 It may be greater than or equal to less than 0.50.
  • the carbon black of this embodiment preferably has a hydrochloric acid absorption amount of 39 mL/5 g or more.
  • the amount of hydrochloric acid absorbed is the amount of hydrochloric acid that can be retained on the particle surface of carbon black and in the voids formed by the structure and agglomerate (secondary agglomeration of the structure), and is an index for evaluating the degree of development of the structure and agglomerate.
  • the carbon black structure is a structure in which primary particles are connected.
  • the structure of carbon black develops into a complex entangled shape as the primary particles become smaller in size.
  • Carbon black is characterized by its thermal history during synthesis (e.g. thermal history caused by thermal decomposition and combustion reactions of fuel oil, thermal decomposition and combustion reactions of raw materials, rapid cooling with cooling medium and reaction termination, etc.), collision frequency of primary particles.
  • thermal history during synthesis e.g. thermal history caused by thermal decomposition and combustion reactions of fuel oil, thermal decomposition and combustion reactions of raw materials, rapid cooling with cooling medium and reaction termination, etc.
  • collision frequency of primary particles e.g. thermal history caused by thermal decomposition and combustion reactions of fuel oil, thermal decomposition and combustion reactions of raw materials, rapid cooling with cooling medium and reaction termination, etc.
  • the degree of development of structure and agglomerate varies greatly depending on the difference in structure and agglomerate (secondary aggregation of structure).
  • the amount of hydrochloric acid absorbed can be measured according to JIS K1469:2003. Specifically, it is determined by adding hydrochloric acid little by little to 5 g of carbon black in an Erlenmeyer flask, shaking it, and measuring the amount of hydrochloric acid required to form a lump.
  • the amount of hydrochloric acid absorbed may be 39 mL/5 g or more, 40 mL/5 g or more, or 41 mL/5 g or more, from the viewpoint of obtaining the above effects more significantly.
  • the amount of hydrochloric acid absorbed by the carbon black of this embodiment is such that the slurry viscosity described below is 1500 mPa ⁇ s or less.
  • the upper limit of the preferable range of hydrochloric acid absorption amount may be defined by the slurry viscosity described below.
  • the hydrochloric acid absorption amount may be, for example, 49 mL/5 g or less, or 48 mL/5 g or less, from the viewpoint that the slurry viscosity described below is likely to be 1500 mPa ⁇ s or less. That is, in the carbon black of this embodiment, the hydrochloric acid absorption amount is, for example, 39 to 49 mL/5 g, 39 to 48 mL/5 g, 40 to 49 mL/5 g, 40 to 48 mL/5 g, 41 to 49 mL/5 g, or 41 to 48 mL. /5g.
  • the carbon black of this embodiment preferably has a slurry viscosity of 400 mPa ⁇ s or more and 1500 mPa ⁇ s or less.
  • the slurry viscosity refers to the viscosity of a slurry in which 3% by mass of carbon black is dispersed using N-methyl-2-pyrrolidone as a dispersion medium. More specifically, 3% by mass of carbon black and 97% by mass of N-methyl-2-pyrrolidone as a dispersion medium were mixed using a rotation-revolution mixer ("Awatori Rentaro ARV-310" manufactured by Shinky Co., Ltd.). A slurry was obtained by kneading at a rotational speed of 2000 rpm for 30 minutes, and the viscosity of this slurry at 25° C.
  • the viscosity at a shear rate of 10 s -1 is determined by changing the shear rate from 0.01 s -1 to 100 s -1 .
  • the viscosity measured in this manner at 25° C. and a shear rate of 10 s ⁇ 1 is defined as the slurry viscosity.
  • Slurry viscosity is an indicator of the dispersibility and stability of carbon black under shear.
  • carbon black with a slurry viscosity of 400 mPa ⁇ s or more and 1500 mPa ⁇ s or less is used as a carrier for a fuel cell catalyst
  • the catalyst paste which is a mixture of a fuel cell catalyst, an electrolyte, and a solvent, tends to be uniform.
  • the electrode catalyst layer obtained by coating the fuel cell catalyst is difficult to form aggregated particles. Therefore, it becomes easier to obtain better long-term reliability and reaction efficiency.
  • the slurry viscosity may be 450 mPa ⁇ s or more or 500 mPa ⁇ s or more from the viewpoint of obtaining the above effects more significantly.
  • the slurry viscosity may be 1400 mPa ⁇ s or less, or 1300 mPa ⁇ s or less from the viewpoint of obtaining the above effects more significantly. That is, in the carbon black of this embodiment, the slurry viscosity is, for example, 400 to 1500 mPa ⁇ s, 400 to 1400 mPa ⁇ s, 400 to 1300 mPa ⁇ s, 450 to 1500 mPa ⁇ s, 450 to 1400 mPa ⁇ s, 450 to 1300 mPa ⁇ s. , 500 to 1500 mPa ⁇ s, 500 to 1400 mPa ⁇ s or 500 to 1300 mPa ⁇ s.
  • the slurry viscosity of carbon black may be adjusted as appropriate depending on the average primary particle diameter of carbon black, the surface properties of carbon black, the shape of the structure of carbon black, etc.
  • the DBP absorption amount of the carbon black of this embodiment may be, for example, 200 mL/100 g or more, 210 mL/100 g or more, or 220 mL/100 g or more. Further, the DBP absorption amount of the carbon black of this embodiment may be, for example, 400 mL/100 g or less, 390 mL/100 g or less, or 380 mL/100 g or less.
  • the DBP absorption amount of the carbon black of this embodiment is, for example, 200 to 400 mL/100 g, 200 to 390 mL/100 g, 200 to 380 mL/100 g, 210 to 400 mL/100 g, 210 to 390 mL/100 g, 210 to 380 mL/100 g. , 220 to 400 mL/100 g, 220 to 390 mL/100 g, or 220 to 380 mL/100 g.
  • the DBP absorption amount is an index for evaluating the ability to absorb dibutyl phthalate (DBP) in the voids formed by the particle surface and structure of carbon black.
  • DBP absorption amount indicates a value obtained by converting a value measured by the method described in JIS K6221 Method B into a value equivalent to JIS K6217-4:2008 using the following formula (a).
  • DBP absorption amount (A-10.974)/0.7833...(a) [Wherein, A represents the equivalent value of DBP absorption measured by the method described in JIS K6221. ]
  • Carbon black with a developed structure has more necks formed by fusion of primary particles and more voids formed between particles, so the amount of DBP absorbed increases. If the DBP absorption amount is too small, the viscosity of the catalyst paste made by mixing the fuel cell catalyst, electrolyte, and solvent will become too low, making it difficult to apply shearing force due to mixing, and making it difficult to obtain good dispersibility. be. On the other hand, if the amount of DBP absorbed is too large, the viscosity of the catalyst paste may become too high, making it difficult to obtain good dispersibility.
  • the DBP absorption amount is preferably within the above range.
  • the average primary particle size of the carbon black of this embodiment may be, for example, less than 30 nm, less than 29 nm, less than 28 nm, less than 27 nm, less than 26 nm, or less than 25 nm. Further, the average primary particle diameter of the carbon black of this embodiment may be, for example, 10 nm or more. According to the findings of the present inventors, when comparing two types of carbon black that satisfy the above ratio (S 2 /S 1 ) with similar specific surface areas but different average primary particle sizes, it was found that carbon black with a small particle size In the case of carbon black, the particle size of metal particles formed on the carbon black is smaller.
  • carbon black with a large particle size has a high specific surface area due to a porous surface, while carbon black with a small particle size can achieve a high specific surface area even if the surface is relatively smooth. This is thought to be because the number of surfaces in contact increases, and the number of reaction fields for forming metal particles increases.
  • the average primary particle size of carbon black can be determined by measuring the primary particle size of 100 or more carbon black particles randomly selected from a 50,000x magnified image using a transmission electron microscope (TEM) and calculating the average value. can.
  • TEM transmission electron microscope
  • the primary particles of carbon black have a small aspect ratio and a shape close to a true sphere, they are not completely true spheres. Therefore, in this embodiment, the largest line segment connecting two points on the outer periphery of the primary particle in the TEM image is defined as the primary particle diameter of carbon black.
  • the ash content of the carbon black of this embodiment may be, for example, 0.05% by mass or less, 0.03% by mass or less, or 0.02% by mass or less.
  • the ash content can be measured according to JIS K1469:2003, and can be reduced, for example, by classifying carbon black with a device such as a dry cyclone.
  • the sulfur content of the carbon black of this embodiment may be, for example, 50 mass ppm or less.
  • the sulfur content in carbon black exists as acidic functional groups such as sulfuric acid groups on the surface of carbon black.
  • generation of gases such as SOx due to electrochemical reactions inside the battery is suppressed, and deterioration of fuel cell performance due to the gases is significantly suppressed.
  • the sulfur content of carbon black can be calculated by burning carbon black in an oxygen stream, absorbing the generated combustion gas into a hydrogen peroxide solution, and measuring it using ion chromatography.
  • the method for producing carbon black of this embodiment is not particularly limited.
  • raw materials such as hydrocarbons are supplied from a nozzle installed upstream of a reactor, and carbon black is produced by a thermal decomposition reaction and/or a combustion reaction.
  • Carbon black can be obtained by generating black and collecting it from a bag filter directly connected downstream of the reactor.
  • the raw materials used are not particularly limited, and include gaseous hydrocarbons such as acetylene, methane, ethane, propane, ethylene, propylene, butadiene, and oils such as toluene, benzene, xylene, gasoline, kerosene, light oil, and heavy oil. Hydrocarbons can be used. Among them, it is preferable to use acetylene, which has few impurities. Acetylene has a larger heat of decomposition than other raw materials, and the temperature inside the reactor can be raised, so carbon black nucleation dominates particle growth due to addition reactions, reducing the primary particle size of carbon black. be able to.
  • gaseous hydrocarbons such as acetylene, methane, ethane, propane, ethylene, propylene, butadiene, and oils such as toluene, benzene, xylene, gasoline, kerosene, light oil, and heavy oil. Hydrocarbons can be used. Among
  • the present inventors found that it is effective to use multiple raw materials and heat the raw materials before supplying them to the reactor. I discovered that.
  • carbon black produced through the high-temperature section of the reactor and carbon black produced via the low-temperature section coexist, resulting in large variations in properties, but by using multiple raw materials, It is thought that the proportion of polycyclic aromatic hydrocarbons present on the surface of carbon black decreased because the temperature in the reactor became uniform and the reaction history of thermal decomposition and combustion became uniform.
  • heating the raw materials promoted the mixing of multiple raw materials, making it possible to form a more uniform temperature field.
  • the plurality of raw materials are mixed before being supplied to the reactor. When using oily hydrocarbons, it is preferable to gasify them by heating and then supply them.
  • the heating method is not particularly limited, and for example, a tank or transport piping can be heated by heat exchange with a heating medium.
  • oxygen, hydrogen, nitrogen, steam, etc. it is preferable to supply oxygen, hydrogen, nitrogen, steam, etc. to the reactor separately from the raw material serving as the carbon source.
  • gases other than raw materials promote gas agitation in the reactor and increase the frequency of collision and fusion of primary particles of carbon black produced from raw materials.
  • gases other than raw materials carbon black structure develops, and the amount of DBP absorbed tends to increase.
  • oxygen is preferable to use oxygen as the gas other than the raw material. When oxygen is used, part of the raw material is combusted and the temperature inside the reactor increases, making it easier to obtain carbon black with a small particle size and a high specific surface area.
  • a plurality of gases can also be used as the gas other than the raw material.
  • the gas other than the raw material is preferably supplied to the upstream part of the reactor, and is preferably supplied from a different nozzle from that for the raw material.
  • the raw materials supplied from the upstream portion are efficiently stirred, and the structure is facilitated to develop.
  • a cooling medium such as water is sometimes introduced from the downstream part of the reactor to thermally decompose the raw material and stop the combustion reaction, but no effect on structure development has been observed.
  • the fuel cell catalyst of this embodiment has at least one metal particle selected from the group consisting of platinum particles and platinum alloy particles supported on the surface of a fuel cell catalyst carrier (carbon black).
  • the metal particles are strongly supported on the surface of the carrier.
  • the average particle size of the metal particles may be, for example, 2 nm or more. When the average particle size is 2 nm or more, dissolution, corrosion, etc. during potential fluctuations are suppressed.
  • the average particle size of the metal particles may be, for example, 5 nm or less. When the average particle size is 5 nm or less, a sufficient active surface area is ensured, and better fuel cell characteristics are likely to be obtained.
  • the particle size of the metal particles is determined by the length of the longest line segment connecting two points on the outer periphery of the metal particles, as determined by observation with a transmission electron microscope.
  • the average particle size of metal particles can be determined by measuring the particle size of 1000 metal particles and calculating the average value.
  • Platinum particles are particles composed of platinum.
  • Platinum alloy particles are particles composed of an alloy of platinum and other metals (hereinafter referred to as alloy forming metals).
  • alloy forming metals include palladium, rhodium, iridium, ruthenium, iron, titanium, nickel, cobalt, gold, silver, copper, chromium, manganese, molybdenum, tungsten, aluminum, silicon, rhenium, zinc, tin, and the like.
  • platinum-ruthenium alloys are preferred because they are effective in preventing carbon monoxide poisoning.
  • composition of the alloy is not particularly limited, but may be, for example, 30 to 90% by mass of platinum and 10 to 70% by mass of alloy forming metal.
  • the amount of metal particles supported in the fuel cell catalyst may be, for example, 5 parts by mass or more and 80 parts by mass or less, based on 100 parts by mass of carbon black.
  • the method for supporting metal particles on carbon black is not particularly limited, and may be, for example, the following method. Carbon black is suspended in water to form a slurry, a metal source is added to this to form a mixed solution A, and sodium borohydride is added in an amount equivalent to 10 times the amount of the metal to form metal particles on the surface of the carbon black. After precipitation, a fuel cell catalyst is obtained by filtering, washing, and drying.
  • platinum sources include hexachloroplatinum aqueous solution, hexahydroxoplatinum aqueous solution, dinitrodiammine platinum aqueous solution, and the like.
  • examples of the alloy-forming metal source include a ruthenium (III) trichloride aqueous solution.
  • a pH adjuster such as an aqueous sodium hydroxide solution may be added as appropriate.
  • the fuel cell catalyst may be subjected to an annealing treatment after supporting metal particles on carbon black, and then used in a fuel cell.
  • the annealing treatment can be performed by heating to 800 to 1000° C., for example, in an inert atmosphere such as argon gas or nitrogen gas, or a reducing atmosphere such as hydrogen gas.
  • the evaluation of the fuel cell catalyst of this embodiment can be performed as follows.
  • a fuel cell catalyst is mixed with a Nafion solution and alcohol is added to form a paste, which is applied to one side of carbon paper and dried to form an electrode catalyst layer (electrode for evaluation).
  • an evaluation electrode was placed on one side of the Nafion membrane (perfluorosulfonic acid electrolyte membrane), and a known electrode was placed on the other side, and thermocompression bonded using a hot press at 130°C. In this way, an electrolyte membrane-electrode assembly (MEA) is obtained.
  • MEA electrolyte membrane-electrode assembly
  • a single cell is completed by sandwiching the MEA between a separator and a current collector plate, and the fuel cell can be evaluated by connecting an electronic load device and a gas supply device. Moreover, the above evaluation can be performed more easily by using a commercially available fuel cell single cell evaluation device.
  • the electrode catalyst layer of this embodiment contains the above fuel cell catalyst and electrolyte.
  • the electrolyte is not particularly limited, and electrolytes used in known fuel cells can be used without particular limitation.
  • perfluorosulfonic acid polymers are preferably used, and examples thereof include Nafion (manufactured by Dupont), Aciplex (manufactured by Asahi Kasei), Flemion (manufactured by Asahi Glass), and the like.
  • the thickness of the electrode catalyst layer may be, for example, 5 ⁇ m or more, or 10 ⁇ m or more. Further, the thickness of the electrode catalyst layer may be, for example, 50 ⁇ m or less, 40 ⁇ m or less, or 30 ⁇ m or less. That is, the thickness of the electrode catalyst layer may be, for example, 5 to 50 ⁇ m, 5 to 40 ⁇ m, 5 to 30 ⁇ m, 10 to 50 ⁇ m, 10 to 40 ⁇ m, or 10 to 30 ⁇ m.
  • the fuel cell of this embodiment includes the electrode catalyst layer of this embodiment described above.
  • the structure other than the electrode catalyst layer is not particularly limited, and may be the same structure as a known fuel cell.
  • the fuel cell of this embodiment may include, for example, a first separator, an anode electrode catalyst layer, an electrolyte membrane, a cathode electrode catalyst layer, and a second separator. It may include a separator, a first gas diffusion layer, an anode electrode catalyst layer, an electrolyte membrane, a cathode electrode catalyst layer, a second gas diffusion layer, and a second separator.
  • one of the anode electrode catalyst layer and the cathode electrode catalyst layer may be the electrode catalyst layer of this embodiment described above.
  • the first separator and the second separator may be any separator provided with a gas flow path.
  • the first separator and the second separator may be separators used in known fuel cells.
  • the first separator and the second separator may be made of, for example, stainless steel, aluminum alloy, carbon, or the like.
  • the first gas diffusion layer and the second gas diffusion layer may be gas diffusion layers used in known fuel cells.
  • the first gas diffusion layer and the second gas diffusion layer are, for example, a coating layer (for example, a coating made of a carbon material and a water repellent material) on the surface of a base material (for example, carbon fiber paper, woven fabric, nonwoven fabric, etc.). layer) may be provided.
  • One of the anode electrode catalyst layer and the cathode electrode catalyst layer may be the electrode catalyst layer of the above-described present embodiment, and the other may be another electrode catalyst layer. Moreover, both the anode electrode catalyst layer and the cathode electrode catalyst layer may be the electrode catalyst layers of the above-described present embodiment. Electrode catalyst layers other than the electrode catalyst layer of this embodiment may be electrode catalyst layers used in known fuel cells.
  • the electrolyte membrane may be an electrolyte membrane used in known fuel cells.
  • a perfluorosulfonic acid polymer is preferably used for the electrolyte membrane, and may be, for example, Nafion (manufactured by Dupont), Aciplex (manufactured by Asahi Kasei), Flemion (manufactured by Asahi Glass), or the like.
  • Example 1 Manufacture of carbon black> From a nozzle installed at the upstream part of a carbon black reactor (furnace length: 6 m, furnace diameter: 0.65 m), acetylene as a raw material is fed at a rate of 12 Nm 3 /h, toluene at a rate of 32 kg/h, and oxygen as a gas other than the raw material at a rate of 21 Nm 3 /h . h to produce carbon black, which was collected by a bag filter installed downstream of the reactor. Thereafter, it was passed through a dry cyclone device and a magnet for iron removal and collected into a tank. Note that acetylene, toluene, and oxygen were heated to 115° C. and then supplied to the reactor. The following physical properties of the obtained carbon black were measured. The evaluation results are shown in Tables 1 and 2.
  • FIG. 1 is a diagram showing a chart of m/z 57 and m/z 128 detected by temperature-programmed desorption gas analysis of the carbon black of Example 1.
  • the obtained absorption liquid was introduced into an ion chromatography analyzer, the peak area of sulfate ions was measured, and the sulfur content in the sample was calculated based on a calibration curve prepared in advance from a sulfate ion standard solution.
  • Platinum particles were supported on carbon black using the following method.
  • a platinum solution prepare 1000 g (platinum content: 46 g) of a dinitrodiammine platinum nitric acid solution with a platinum concentration of 4.6% by mass. 46 g of carbon black is immersed in this platinum solution, and after stirring, 100% ethanol is added as a reducing agent. 100 mL of was added. Next, the mixture was stirred and mixed under heating and reflux for 7 hours, so that the platinum particles were supported on the carbon black. Filtration and drying were performed to obtain a fuel cell catalyst having a supported amount of platinum particles of 50 parts by mass based on 100 parts by mass of carbon black.
  • the particle size of 1000 platinum particles was measured by TEM observation (magnification: 100,000 times), and the average value was determined.
  • the evaluation results are shown in Table 2.
  • the obtained fuel cell catalyst was annealed by holding it at 900° C. for 1 hour in 100% hydrogen gas.
  • Electrode catalyst layer To 0.05 g of a fuel cell catalyst, 0.1 g of a 5% by mass Nafion solution (Nafion 1100EW, manufactured by Sigma-Aldrich) and 0.6 g of 2-propanol were added and mixed to form a catalyst paste. Next, a catalyst paste was applied to carbon paper so that the platinum content was 0.3 mg/cm 2 and dried at room temperature to obtain an electrode catalyst layer. The surface of the obtained electrode catalyst layer was observed using a SEM (magnification: 1000 times), and the number of aggregated particles of 10 ⁇ m or more existing in an area of 100 ⁇ m in length ⁇ 100 ⁇ m in width was determined. Here, the size of the aggregated particles was determined from the diameter of the smallest circle that could surround each aggregated particle. The results are shown in Table 3.
  • a fuel cell was manufactured using the electrode catalyst layer obtained above as a cathode electrode.
  • an anode electrode was produced in the same manner as ⁇ Manufacture of electrode catalyst layer> above, except that the fuel cell catalyst was changed to "TEC10E50E" (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.).
  • the Nafion membrane, the cathode electrode, and the anode electrode were overlapped so that the cathode electrode and the anode electrode faced each other with the Nafion membrane in between, and pressed at 130° C. and 9.8 MPa for 3 minutes to obtain an MEA.
  • a separator, a gasket, and an end plate were stacked on the upper and lower surfaces of the MEA in this order, and fixed with four screws to produce a fuel cell.
  • Example 2 and 3 Carbon black was produced in the same manner as in Example 1, except that the amount of oxygen supplied in ⁇ Production of carbon black> was changed to 22 Nm 3 /h (Example 2) or 24 Nm 3 /h (Example 3). and evaluated. The results are shown in Tables 1 and 2. Further, using the obtained carbon black, a fuel cell catalyst, an electrode catalyst layer, and a fuel cell were produced and evaluated in the same manner as in Example 1. The results are shown in Table 3.
  • Example 4 In ⁇ Production of carbon black>, carbon black was produced and evaluated in the same manner as in Example 1, except that the temperature during supply of toluene was changed to 100°C. The results are shown in Tables 1 and 2. Further, using the obtained carbon black, a fuel cell catalyst, an electrode catalyst layer, and a fuel cell were produced and evaluated in the same manner as in Example 1. The results are shown in Table 3.
  • Example 5 In ⁇ Manufacture of carbon black>, carbon black was produced and evaluated in the same manner as in Example 1, except that the temperature during acetylene supply was changed to 85 ° C., and the temperature during toluene supply was changed to 100 ° C. . The results are shown in Tables 1 and 2. Further, using the obtained carbon black, a fuel cell catalyst, an electrode catalyst layer, and a fuel cell were produced and evaluated in the same manner as in Example 1. The results are shown in Table 3.
  • Example 6 In ⁇ Production of carbon black>, carbon black was produced and evaluated in the same manner as in Example 1, except that the temperature during acetylene supply was changed to 85 ° C., and the temperature during toluene supply was changed to 85 ° C. . The results are shown in Tables 1 and 2. Further, using the obtained carbon black, a fuel cell catalyst, an electrode catalyst layer, and a fuel cell were produced and evaluated in the same manner as in Example 1. The results are shown in Table 3.
  • Example 7 Carbon black was produced and evaluated in the same manner as in Example 1, except that the acetylene supply rate was changed to 13 Nm 3 /h, the toluene supply rate was changed to 35 kg/h, and the oxygen supply rate was changed to 26 Nm 3 /h. did. The results are shown in Tables 1 and 2. Further, using the obtained carbon black, a fuel cell catalyst, an electrode catalyst layer, and a fuel cell were produced and evaluated in the same manner as in Example 1. The results are shown in Table 3.
  • Example 8 Carbon black was produced and evaluated in the same manner as in Example 1, except that 32 kg/h of benzene was heated to 115° C. and supplied instead of toluene. The results are shown in Tables 1 and 2. Further, using the obtained carbon black, a fuel cell catalyst, an electrode catalyst layer, and a fuel cell were produced and evaluated in the same manner as in Example 1. The results are shown in Table 3.
  • Example 1 Carbon black was produced and evaluated in the same manner as in Example 1, except that the amount of oxygen supplied was changed to 20 Nm 3 /h. The results are shown in Tables 1 and 2. Further, using the obtained carbon black, a fuel cell catalyst, an electrode catalyst layer, and a fuel cell were produced and evaluated in the same manner as in Example 1. The results are shown in Table 3.
  • Carbon black was prepared and evaluated in the same manner as in Example 1, except that the acetylene supply rate was changed to 11 Nm 3 /h, the toluene supply rate was changed to 30 kg/h, and the oxygen supply rate was changed to 24 Nm 3 /h. .
  • the results are shown in Tables 1 and 2. Further, using the obtained carbon black, a fuel cell catalyst, an electrode catalyst layer, and a fuel cell were produced and evaluated in the same manner as in Example 1. The results are shown in Table 3.
  • Example 9 The carbon black obtained in Comparative Example 1 was oxidized in an electric furnace heated to 720° C. to obtain carbon black. The obtained carbon black was evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2. Further, using the obtained carbon black, a fuel cell catalyst, an electrode catalyst layer, and a fuel cell were produced and evaluated in the same manner as in Example 1. The results are shown in Table 3.
  • Example 10 Carbon black was produced and evaluated in the same manner as in Example 1, except that the classification conditions of the dry cyclone device were changed to adjust the ash content. The results are shown in Tables 1 and 2. Further, using the obtained carbon black, a fuel cell catalyst, an electrode catalyst layer, and a fuel cell were produced and evaluated in the same manner as in Example 1. The results are shown in Table 3.
  • Example 11 Carbon black was produced and evaluated in the same manner as in Example 1, except that the iron content was adjusted by changing the magnetic flux density conditions of the iron removal magnet. The results are shown in Tables 1 and 2. Further, using the obtained carbon black, a fuel cell catalyst, an electrode catalyst layer, and a fuel cell were produced and evaluated in the same manner as in Example 1. The results are shown in Table 3.
  • the carbon black of the example as a carrier for the fuel cell catalyst, agglomeration in the electrode catalyst layer was suppressed and a high-performance fuel cell was obtained. It was confirmed that the catalyst is capable of achieving both high dispersibility and high reaction efficiency.
  • the fuel cell catalyst carrier of the present invention can be suitably used to realize a fuel cell catalyst that can achieve both high dispersibility and high reaction efficiency. Further, the fuel cell catalyst of the present invention can achieve both high dispersibility and high reaction efficiency, and can be suitably used as a fuel cell catalyst.

Abstract

The present invention provides a catalyst carrier for fuel cells, the catalyst carrier being formed of carbon black, wherein: the specific surface area is 170 m2/g to 400 m2/g; and the ratio (S2/S1) of the peak area (S2)of the m/z 128 peak to the peak area (S1) of the m/z 57 peak as determined by programmed-temperature desorption gas analysis is less than 2.00.

Description

燃料電池用触媒用担体、燃料電池用触媒、電極触媒層及び燃料電池Fuel cell catalyst carrier, fuel cell catalyst, electrode catalyst layer, and fuel cell
　本発明は、燃料電池用触媒用担体、燃料電池用触媒、電極触媒層及び燃料電池に関する。 The present invention relates to a fuel cell catalyst carrier, a fuel cell catalyst, an electrode catalyst layer, and a fuel cell.
　従来から、固体高分子型燃料電池として、セパレータ／ガス拡散層／電極触媒層／電解質膜／電極触媒層／ガス拡散層／セパレータのセル構造を有する燃料電池が利用されている。ここで、電極触媒層としては、例えば、白金粒子等の金属粒子が担持されたカーボンブラックを、電解質中に分散させた層が用いられている。 Conventionally, fuel cells having a cell structure of separator/gas diffusion layer/electrode catalyst layer/electrolyte membrane/electrode catalyst layer/gas diffusion layer/separator have been used as polymer electrolyte fuel cells. Here, as the electrode catalyst layer, for example, a layer in which carbon black carrying metal particles such as platinum particles is dispersed in an electrolyte is used.
　電極触媒層中でカーボンブラックを効率良く分散させる方法として、例えば、触媒担持カーボンブラックとイオン交換樹脂と溶媒とを混合して、外部剪断機で外部剪断を行う第１の工程と、内部剪断機で内部剪断（液－液剪断）を行う第２の工程と、再度外部剪断を行う第３の工程と、を備える燃料電池用触媒ペーストの製造方法が開示されている。 As a method for efficiently dispersing carbon black in an electrode catalyst layer, for example, a first step of mixing catalyst-supported carbon black, an ion exchange resin, and a solvent and externally shearing the mixture with an external shearer, and an internal shearer A method for producing a catalyst paste for a fuel cell is disclosed, which includes a second step of performing internal shearing (liquid-liquid shearing), and a third step of performing external shearing again.
特開２００５－２１６６６１号公報Japanese Patent Application Publication No. 2005-216661
　しかし、特許文献１に記載の方法では、装置の解砕能力に限界があるため、必ずしも十分な分散性が得られない場合があり、また、解砕処理に係る工程による異物の混入、生産性の低下等の問題が生じる場合もあった。 However, in the method described in Patent Document 1, there is a limit to the crushing capacity of the device, so sufficient dispersibility may not always be obtained, and the process of crushing may cause contamination of foreign matter and productivity. In some cases, problems such as a decrease in
　また、燃料電池では、高価な金属粒子の性能を最大限得る観点から、電極触媒層中の金属粒子の単位質量当たりの触媒活性（電極触媒層の反応効率）が高いことが望まれる。 Furthermore, in a fuel cell, from the viewpoint of maximizing the performance of expensive metal particles, it is desired that the metal particles in the electrode catalyst layer have high catalytic activity per unit mass (reaction efficiency of the electrode catalyst layer).
　本発明は、高い分散性と高い反応効率とを両立可能な燃料電池用触媒を実現可能な、燃料電池用触媒用担体を提供することを目的とする。また、本発明は、高い分散性と高い反応効率とを両立可能な燃料電池用触媒を提供することを目的とする。また、本発明は、上記燃料電池用触媒を含有する電極触媒層及び燃料電池を提供することを目的とする。 An object of the present invention is to provide a carrier for a fuel cell catalyst that can realize a fuel cell catalyst that can achieve both high dispersibility and high reaction efficiency. Another object of the present invention is to provide a fuel cell catalyst that can achieve both high dispersibility and high reaction efficiency. Another object of the present invention is to provide an electrode catalyst layer and a fuel cell containing the above fuel cell catalyst.
　本発明は、例えば、下記＜１＞～＜８＞に関する。
＜１＞
　カーボンブラックからなる燃料電池用触媒用担体であって、
　比表面積が１７０ｍ２／ｇ以上４００ｍ２／ｇ以下であり、
　昇温脱離ガス分析法により検出される、ｍ／ｚ５７のピークのピーク面積（Ｓ１）に対するｍ／ｚ１２８のピークのピーク面積（Ｓ２）の比（Ｓ２／Ｓ１）が２．００未満である、
　燃料電池用触媒用担体。
＜２＞
　Ｎ－メチル－２－ピロリドンを分散媒とした３質量％のスラリーとしたとき、２５℃、せん断速度１０ｓ－１におけるスラリー粘度が、４００ｍＰａ・ｓ以上１５００ｍＰａ・ｓ以下となる、＜１＞に記載の燃料電池用触媒用担体。
＜３＞
　塩酸吸液量が３９ｍＬ／５ｇ以上である、＜１＞又は＜２＞に記載の燃料電池用触媒用担体。
＜４＞
　ＤＢＰ吸収量が２００ｍＬ／１００ｇ以上４００ｍＬ／１００ｇ以下である、＜１＞～＜３＞のいずれかに記載の燃料電池用触媒用担体。
＜５＞
　＜１＞～＜４＞のいずれかに記載の燃料電池用触媒用担体に、白金粒子及び白金合金粒子からなる群より選択される少なくとも一種の金属粒子を担持させてなる、燃料電池用触媒。
＜６＞
　＜５＞に記載の燃料電池用触媒と電解質とを含有する、電極触媒層。
＜７＞
　＜６＞に記載の電極触媒層を備える、燃料電池。
＜８＞
　第一のセパレータと、第一のガス拡散層と、アノード電極触媒層と、電解質膜と、カソード電極触媒層と、第二のガス拡散層と、第二のセパレータと、を備え、
　前記アノード電極触媒層及び前記カソード電極触媒層のうち、少なくとも一方が＜６＞に記載の電極触媒層である、燃料電池。 The present invention relates to, for example, the following <1> to <8>.
<1>
A fuel cell catalyst carrier made of carbon black,
The specific surface area is 170 m 2 /g or more and 400 m 2 /g or less,
The ratio (S 2 /S 1 ) of the peak area (S 1 ) of the m/z 57 peak to the peak area (S 2 ) of the m/z 128 peak detected by temperature programmed desorption gas analysis is 2.00. is less than
Support for catalysts for fuel cells.
<2>
As described in <1>, when a 3% by mass slurry is prepared using N-methyl-2-pyrrolidone as a dispersion medium, the slurry viscosity at 25°C and a shear rate of 10 s -1 is 400 mPa s or more and 1500 mPa s or less. catalyst carrier for fuel cells.
<3>
The fuel cell catalyst carrier according to <1> or <2>, which has a hydrochloric acid absorption amount of 39 mL/5 g or more.
<4>
The fuel cell catalyst carrier according to any one of <1> to <3>, which has a DBP absorption amount of 200 mL/100 g or more and 400 mL/100 g or less.
<5>
A fuel cell catalyst comprising at least one metal particle selected from the group consisting of platinum particles and platinum alloy particles supported on the fuel cell catalyst carrier according to any one of <1> to <4>.
<6>
An electrode catalyst layer containing the fuel cell catalyst and electrolyte according to <5>.
<7>
A fuel cell comprising the electrode catalyst layer according to <6>.
<8>
comprising a first separator, a first gas diffusion layer, an anode electrode catalyst layer, an electrolyte membrane, a cathode electrode catalyst layer, a second gas diffusion layer, and a second separator,
A fuel cell, wherein at least one of the anode electrode catalyst layer and the cathode electrode catalyst layer is the electrode catalyst layer according to <6>.
　本発明によれば、高い分散性と高い反応効率とを両立可能な燃料電池用触媒を実現可能な、燃料電池用触媒用担体が提供される。また、本発明によれば、高い分散性と高い反応効率とを両立可能な燃料電池用触媒が提供される。更に、本発明によれば、上記燃料電池用触媒を含有する電極触媒層及び燃料電池は提供される。 According to the present invention, a carrier for a fuel cell catalyst is provided that can realize a fuel cell catalyst that can achieve both high dispersibility and high reaction efficiency. Further, according to the present invention, a fuel cell catalyst is provided that is capable of achieving both high dispersibility and high reaction efficiency. Furthermore, according to the present invention, an electrode catalyst layer and a fuel cell containing the above fuel cell catalyst are provided.
実施例１で用いたカーボンブラックの、昇温脱離ガス分析法により検出されるｍ／ｚ５７及びｍ／ｚ１２８のチャートを示す図である。FIG. 2 is a diagram showing a chart of m/z 57 and m/z 128 of carbon black used in Example 1, detected by temperature-programmed desorption gas analysis.
　以下、本発明の好適な実施形態について詳細に説明する。なお、本発明は、以下に説明する実施形態に限定されるものではない。なお、本明細書において、特にことわりがない限り、「～」を用いて示される数値範囲は、左側の数値「以上」且つ右側の数値「以下」の範囲を意味する。例えば、「Ａ～Ｂ」は、Ａ以上Ｂ以下であるという意味である。 Hereinafter, preferred embodiments of the present invention will be described in detail. Note that the present invention is not limited to the embodiments described below. In this specification, unless otherwise specified, a numerical range indicated using "~" means a range from "more than" the number on the left side to "less than" the number on the right side. For example, "A to B" means greater than or equal to A and less than or equal to B.
＜燃料電池用触媒用担体＞
　本実施形態の燃料電池用触媒用担体は、カーボンブラックからなり、後述の金属粒子の担持によって燃料電池用触媒を形成する担体である。 <Catalyst carrier for fuel cells>
The fuel cell catalyst carrier of this embodiment is made of carbon black, and is a carrier that forms a fuel cell catalyst by supporting metal particles, which will be described later.
　本実施形態の燃料電池用触媒用担体（以下、単にカーボンブラックともいう。）は、１７０ｍ２／ｇ以上４００ｍ２／ｇ以下の比表面積を有する。 The fuel cell catalyst carrier (hereinafter also simply referred to as carbon black) of the present embodiment has a specific surface area of 170 m 2 /g or more and 400 m 2 /g or less.
　比表面積が１７０ｍ２／ｇより低いと、金属粒子を高分散で担持させることができず、反応効率（金属粒子の単位質量当たりの触媒活性）が低くなる。比表面積が１７０ｍ２／ｇ以上であると、金属粒子を高分散で担持させることができ、反応効率（金属粒子の単位質量当たりの触媒活性）が高くなる。なお、反応効率は、担持量が一定の場合、燃料電池評価における電流電位曲線において、同じ電流値における電圧の高低を比較することで判断でき、当該電圧が高いほど反応効率が高いと言える。上記効果がより顕著に奏される観点から、比表面積は、１８０ｍ２／ｇ以上、１９０ｍ２／ｇ以上、２００ｍ２／ｇ以上、２１０ｍ２／ｇ以上、２２０ｍ２／ｇ以上、又は、２３０ｍ２／ｇ以上であってよい。 When the specific surface area is lower than 170 m 2 /g, metal particles cannot be supported in a highly dispersed manner, and the reaction efficiency (catalytic activity per unit mass of metal particles) becomes low. When the specific surface area is 170 m 2 /g or more, metal particles can be supported in a highly dispersed manner, and the reaction efficiency (catalytic activity per unit mass of metal particles) becomes high. In addition, when the supported amount is constant, the reaction efficiency can be determined by comparing the level of voltage at the same current value in the current potential curve in fuel cell evaluation, and it can be said that the higher the voltage, the higher the reaction efficiency. From the viewpoint of achieving the above effects more significantly, the specific surface area is 180 m 2 /g or more, 190 m 2 /g or more, 200 m 2 /g or more, 210 m 2 /g or more, 220 m 2 /g or more, or 230 m 2 /g or more.
　比表面積が４００ｍ２／ｇを超えると、燃料電池用触媒と電解質と溶媒とを混合した触媒ペーストが不均一になり易く、当該触媒ペーストを塗工して得られる電極触媒層中で、燃料電池用触媒が凝集粒子を形成し易い。電極触媒層中の凝集粒子は、突起発生の原因となってしまい、電解質膜－電極接合体（ＭＥＡ）を損傷させる可能性がある。また、電極触媒層中で燃料電池触媒が凝集すると、ガスと金属粒子との接触面積が小さくなり、反応効率が低下する。本実施形態では、比表面積が４００ｍ２／ｇ以下であるため、均一な触媒ペーストが得られやすく、凝集粒子の少ない電極触媒層が得られやすく、長期信頼性及び反応効率が高くなる。上記効果がより顕著に奏される観点から、比表面積は、３９５ｍ２／ｇ以下、又は、３９０ｍ２／ｇ以下であってもよい。
　すなわち、比表面積は、例えば１７０～４００ｍ２／ｇ、１７０～３９５ｍ２／ｇ、１７０～３９０ｍ２／ｇ、１８０～４００ｍ２／ｇ、１８０～３９５ｍ２／ｇ、１８０～３９０ｍ２／ｇ、１９０～４００ｍ２／ｇ、１９０～３９５ｍ２／ｇ、１９０～３９０ｍ２／ｇ、２００～４００ｍ２／ｇ、２００～３９５ｍ２／ｇ、２００～３９０ｍ２／ｇ、２１０～４００ｍ２／ｇ、２１０～３９５ｍ２／ｇ、２１０～３９０ｍ２／ｇ、２２０～４００ｍ２／ｇ、２２０～３９５ｍ２／ｇ、２２０～３９０ｍ２／ｇ、２３０～４００ｍ２／ｇ、２３０～３９５ｍ２／ｇ又は２３０～３９０ｍ２／ｇであってもよい。 When the specific surface area exceeds 400 m 2 /g, the catalyst paste, which is a mixture of a fuel cell catalyst, an electrolyte, and a solvent, tends to become non-uniform, and in the electrode catalyst layer obtained by coating the catalyst paste, the fuel cell catalyst tends to form agglomerated particles. Agglomerated particles in the electrode catalyst layer cause protrusions and may damage the electrolyte membrane-electrode assembly (MEA). Further, when the fuel cell catalyst aggregates in the electrode catalyst layer, the contact area between the gas and the metal particles becomes smaller, and the reaction efficiency decreases. In this embodiment, since the specific surface area is 400 m 2 /g or less, a uniform catalyst paste is easily obtained, an electrode catalyst layer with few aggregated particles is easily obtained, and long-term reliability and reaction efficiency are improved. From the viewpoint of achieving the above effects more significantly, the specific surface area may be 395 m 2 /g or less, or 390 m 2 /g or less.
That is, the specific surface area is, for example, 170 to 400 m 2 /g, 170 to 395 m 2 /g, 170 to 390 m 2 /g, 180 to 400 m 2 /g, 180 to 395 m 2 /g, 180 to 390 m 2 /g, 190 ～400m 2 /g, 190～395m 2 /g, 190～390m 2 /g, 200～400m 2 /g, 200～395m 2 /g, 200～390m 2 /g, 210～400m 2 /g, 210～ 395m 2 /g, 210-390m 2 /g, 220-400m 2 /g, 220-395m 2 /g, 220-390m 2 /g, 230-400m 2 /g, 230-395m 2 /g or 230-390m 2 /g.
　なお、比表面積は、ＪＩＳ　Ｋ６２１７－２：２０１７のＡ法流通法（熱伝導度測定法）に従って測定される。 Note that the specific surface area is measured according to JIS K6217-2:2017 method A distribution method (thermal conductivity measurement method).
　本実施形態のカーボンブラックにおいて、昇温脱離ガス分析法により検出されるｍ／ｚ５７のピークのピーク面積をＳ１とし、ｍ／ｚ１２８のピークのピーク面積をＳ２としたとき、比（Ｓ２／Ｓ１）は２．００未満である。ここで、比（Ｓ２／Ｓ１）は、カーボンブラック表面に存在する有機成分の割合、例えば脂肪族炭化水素に対する多環芳香族炭化水素の割合、を示している。 In the carbon black of this embodiment, when the peak area of the m/z 57 peak detected by temperature programmed desorption gas analysis is S 1 and the peak area of the m/z 128 peak is S 2 , the ratio (S 2 /S 1 ) is less than 2.00. Here, the ratio (S 2 /S 1 ) indicates the ratio of organic components present on the surface of the carbon black, for example, the ratio of polycyclic aromatic hydrocarbons to aliphatic hydrocarbons.
　なお、例えばＪ．Ｍａｓｓ　Ｓｐｅｃｔｒｏｍ．Ｓｏｃ．Ｊｐｎ．Ｖｏｌ．５４，Ｎｏ．５，２００６において説明されているとおり、ｍ／ｚは、マススペクトルの横軸の値を意味するひとつの記号である。またｍ／ｚの右に添えた数字は、対象とするイオンの質量を統一原子質量単位で割った値を、さらにイオンの電荷数で割って得られる値（無次元量）であり、ｍ／ｚと併記してマススペクトルにおけるピーク位置を示している。 For example, J. Mass Spectrom. Soc. Jpn. Vol. 54, No. 5, 2006, m/z is a symbol that means the value on the horizontal axis of a mass spectrum. The number to the right of m/z is the value (dimensionless quantity) obtained by dividing the mass of the target ion by the unified atomic mass unit and further dividing by the number of charges on the ion. The peak position in the mass spectrum is indicated together with z.
　比（Ｓ２／Ｓ１）は、発生ガス質量分析法（ＥＧＡ－ＭＳ）により求めることができる。具体的には、カーボンブラックを熱分解装置の設置してあるガスクロマトグラフ質量分析計にセットし、大気圧Ｈｅフロー中で５０℃で５分間保持した後、８０℃／ｍｉｎで８００℃まで昇温する。昇温により脱離した成分の質量分析を下記の条件で行い、得られるｍ／ｚ５７のピークのピーク面積（Ｓ１）とｍ／ｚ１２８のピークのピーク面積（Ｓ２）との比をとることで、比（Ｓ２／Ｓ１）が算出される。
　　カラム：　フロンティアラボ社製Ｕｌｔｒａ　ＡＬＬＯＹ－ＤＴＭ（長さ２．５ｍ、０．１５ｍｍＩ．Ｄ、０．４７ｍｍＯ．Ｄ）
　　ガスクロマト導入温度：　３００℃
　　カラム温度：　３００℃　８０分保持
　　スプリット比：　３０：１
　　カラム流量：　１．０ｍＬ／ｍｉｎ
　　イオン化法：　ＥＩ
　　測定範囲：　ｍ／ｚ＝１０～２００ The ratio (S 2 /S 1 ) can be determined by evolved gas mass spectrometry (EGA-MS). Specifically, carbon black was set in a gas chromatograph mass spectrometer equipped with a pyrolysis device, held at 50°C for 5 minutes in an atmospheric pressure He flow, and then heated to 800°C at a rate of 80°C/min. do. Perform mass spectrometry of the components desorbed by increasing the temperature under the following conditions, and calculate the ratio of the peak area (S 1 ) of the peak at m/z 57 to the peak area (S 2 ) of the peak at m/z 128. Then, the ratio (S 2 /S 1 ) is calculated.
Column: Frontier Lab Ultra ALLOY-DTM (length 2.5 m, 0.15 mm I.D, 0.47 mm O.D)
Gas chromatography introduction temperature: 300℃
Column temperature: 300℃ held for 80 minutes Split ratio: 30:1
Column flow rate: 1.0mL/min
Ionization method: EI
Measurement range: m/z=10-200
　なお、本明細書中、ピーク面積とは、昇温脱離ガス分析法において、昇温によりカーボンブラックから脱離して検出された成分（ｍ／ｚ５７又はｍ／ｚ１２８に相当する成分）が示した、温度と各検出強度（任意単位）との関係グラフ（例えば図１）における、強度０である横軸ベースラインと各検出強度の曲線とに囲まれた部分の面積を示す。 In addition, in this specification, the peak area refers to the peak area of a component (component corresponding to m/z 57 or m/z 128) detected by desorption from carbon black due to temperature elevation in the temperature programmed desorption gas analysis method. , shows the area of the portion surrounded by the horizontal axis baseline where the intensity is 0 and the curve of each detection intensity in a graph (for example, FIG. 1) of the relationship between temperature and each detection intensity (arbitrary unit).
　本発明者らは、上記課題を解決するために鋭意検討した結果、高い比表面積を有するカーボンブラックにおいて、昇温脱離ガス分析法によって解析される表面性状が、電極触媒層中の凝集粒子数に大きく影響することを見出した。すなわち、本実施形態のカーボンブラックは、比（Ｓ２／Ｓ１）が２．００未満であることで、高い比表面積を有しながら、実用上十分に低い凝集粒子数を実現できる。 As a result of intensive studies to solve the above problems, the present inventors found that in carbon black having a high specific surface area, the surface properties analyzed by temperature-programmed desorption gas analysis are determined by the number of aggregated particles in the electrode catalyst layer. was found to have a significant influence on That is, the carbon black of this embodiment has a ratio (S 2 /S 1 ) of less than 2.00, so that it can achieve a sufficiently low number of aggregated particles for practical use while having a high specific surface area.
　カーボンブラックの表面には、カーボンブラック合成時の諸反応（例えば、燃料油の熱分解及び燃焼反応、原料の熱分解及び燃焼反応、冷却用媒体による急冷及び反応停止、等）に起因して、有機成分が微量に存在しており、この有機成分が昇温脱離ガス分析法によって検出される。検出されるｍ／ｚ１２８のピークは、ナフタレンに代表される多環芳香族炭化水素由来のピークであり、ｍ／ｚ５７のピークは脂肪族炭化水素由来のピークである。すなわち、比（Ｓ２／Ｓ１）が小さいことが、カーボンブラック表面に存在する多環芳香族炭化水素の割合が少ないことを意味する。本発明者らの知見によれば、高比表面積のカーボンブラックでは表面の有機成分による分散性への寄与が大きくなり、また、強い疎水性を有する多環芳香族炭化水素が表面に存在する割合が少ないと、分散媒との親和性及び濡れ性が高くなり、分散性が向上する。なお、昇温脱離ガス分析法による検出ピークから存在が推察される有機成分は、従来のカーボンブラックに付与される表面官能基とは全く異なるものである。 On the surface of carbon black, due to various reactions during carbon black synthesis (for example, thermal decomposition and combustion reactions of fuel oil, thermal decomposition and combustion reactions of raw materials, rapid cooling with a cooling medium and reaction termination, etc.), A trace amount of organic components are present, and these organic components are detected by temperature-programmed desorption gas analysis. The detected peak at m/z 128 is a peak derived from polycyclic aromatic hydrocarbons typified by naphthalene, and the peak at m/z 57 is a peak derived from aliphatic hydrocarbons. That is, a small ratio (S 2 /S 1 ) means that the proportion of polycyclic aromatic hydrocarbons present on the carbon black surface is small. According to the findings of the present inventors, in carbon black with a high specific surface area, organic components on the surface make a large contribution to dispersibility, and the proportion of polycyclic aromatic hydrocarbons with strong hydrophobicity on the surface increases. If the amount is small, the affinity and wettability with the dispersion medium will be high, and the dispersibility will be improved. Note that the organic component whose presence is inferred from the peak detected by temperature programmed desorption gas analysis is completely different from the surface functional groups imparted to conventional carbon black.
　本実施形態では、比（Ｓ２／Ｓ１）が２．００未満であることで、ストラクチャーの発達した比表面積の高いカーボンブラックであっても、電極触媒層中で凝集し難く、凝集粒子に起因する反応効率の低下及び信頼性の低下が抑制できる。また、均一な電極触媒層が得られやすく、局所的な触媒効率のバラつきが抑制され、高出力電圧で長寿命の燃料電池が得られやすい。 In this embodiment, by setting the ratio (S 2 /S 1 ) to be less than 2.00, even carbon black with a developed structure and a high specific surface area is difficult to aggregate in the electrode catalyst layer and is not formed into aggregated particles. The resulting decrease in reaction efficiency and reliability can be suppressed. In addition, a uniform electrode catalyst layer is easily obtained, local variations in catalyst efficiency are suppressed, and a fuel cell with a high output voltage and long life is easily obtained.
　本実施形態では、カーボンブラックの比表面積が１７０ｍ２／ｓと高いため、電極触媒層中の凝集粒子数を十分に低くするために、比（Ｓ２／Ｓ１）が２．００未満であることが望ましい。また、上記効果がより顕著に得られる観点からは、比（Ｓ２／Ｓ１）は、１．８０未満、１．６０未満、１．４０未満、１．２０未満、１．００未満、０．８０未満、０．６０未満又は０．５０未満であってよい。 In this embodiment, since the specific surface area of carbon black is as high as 170 m 2 /s, the ratio (S 2 /S 1 ) is less than 2.00 in order to sufficiently reduce the number of aggregated particles in the electrode catalyst layer. This is desirable. In addition, from the viewpoint of obtaining the above effects more significantly, the ratio (S 2 /S 1 ) is less than 1.80, less than 1.60, less than 1.40, less than 1.20, less than 1.00, and 0. It may be less than .80, less than 0.60 or less than 0.50.
　比（Ｓ２／Ｓ１）の下限は特に限定されないが、生産性に優れる観点からは、比（Ｓ２／Ｓ１）は、０．０５以上、０．１０以上又は０．２０以上であってよい。
　すなわち、比（Ｓ２／Ｓ１）は、例えば０．０５以上２．００未満、０．０５以上１．８０未満、０．０５以上１．６０未満、０．０５以上１．４０未満、０．０５以上１．２０未満、０．０５以上１．００未満、０．０５以上０．８０未満、０．０５以上０．６０未満、０．０５以上０．５０未満、０．１０以上２．００未満、０．１０以上１．８０未満、０．１０以上１．６０未満、０．１０以上１．４０未満、０．１０以上１．２０未満、０．１０以上１．００未満、０．１０以上０．８０未満、０．１０以上０．６０未満、０．１０以上０．５０未満、０．２０以上２．００未満、０．２０以上１．８０未満、０．２０以上１．６０未満、０．２０以上１．４０未満、０．２０以上１．２０未満、０．２０以上１．００未満、０．２０以上０．８０未満、０．２０以上０．６０未満又は０．２０以上０．５０未満であってもよい。 The lower limit of the ratio (S 2 /S 1 ) is not particularly limited, but from the viewpoint of excellent productivity, the ratio (S 2 /S 1 ) should be 0.05 or more, 0.10 or more, or 0.20 or more. It's fine.
That is, the ratio (S 2 /S 1 ) is, for example, 0.05 or more and less than 2.00, 0.05 or more and less than 1.80, 0.05 or more and less than 1.60, 0.05 or more and less than 1.40, and 0. .05 or more and less than 1.20, 0.05 or more and less than 1.00, 0.05 or more and less than 0.80, 0.05 or more and less than 0.60, 0.05 or more and less than 0.50, 0.10 or more2. Less than 00, 0.10 or more and less than 1.80, 0.10 or more and less than 1.60, 0.10 or more and less than 1.40, 0.10 or more and less than 1.20, 0.10 or more and less than 1.00, 0. 10 or more and less than 0.80, 0.10 or more and less than 0.60, 0.10 or more and less than 0.50, 0.20 or more and less than 2.00, 0.20 or more and less than 1.80, 0.20 or more and less than 1.60 less than 0.20 or more, less than 1.40, 0.20 or more and less than 1.20, 0.20 or more and less than 1.00, 0.20 or more and less than 0.80, 0.20 or more and less than 0.60, or 0.20 It may be greater than or equal to less than 0.50.
　本実施形態のカーボンブラックは、塩酸吸液量が３９ｍＬ／５ｇ以上であることが好ましい。塩酸吸液量は、カーボンブラックの粒子表面や、ストラクチャー及びアグロメレート（ストラクチャーの二次凝集）が作る空隙に保持できる塩酸量であり、ストラクチャー及びアグロメレートの発達度合いを評価する指標である。ストラクチャー及びアグロメレートが十分に発達した構造を有しているカーボンブラックを燃料電池用触媒用担体に用いると、電極触媒層内に、水素ガスやプロトンが効率良く拡散する空隙が形成される。このため、良好な燃料電池特性が得られやすくなる。 The carbon black of this embodiment preferably has a hydrochloric acid absorption amount of 39 mL/5 g or more. The amount of hydrochloric acid absorbed is the amount of hydrochloric acid that can be retained on the particle surface of carbon black and in the voids formed by the structure and agglomerate (secondary agglomeration of the structure), and is an index for evaluating the degree of development of the structure and agglomerate. When carbon black having a sufficiently developed structure and agglomerates is used as a fuel cell catalyst carrier, voids are formed in the electrode catalyst layer in which hydrogen gas and protons can efficiently diffuse. Therefore, it becomes easier to obtain good fuel cell characteristics.
　ここでカーボンブラックのストラクチャーとは一次粒子が連結した構造のことである。カーボンブラックのストラクチャーは、一次粒子の小粒径化に伴い、複雑に絡み合った形状で発達する。カーボンブラックは、合成時の熱履歴（例えば、燃料油の熱分解及び燃焼反応、原料の熱分解及び燃焼反応、冷却用媒体による急冷及び反応停止等に起因する熱履歴）、一次粒子の衝突頻度の違い等によって、ストラクチャー及びアグロメレート（ストラクチャーの二次凝集）の発達度合いが大きく異なる。 Here, the carbon black structure is a structure in which primary particles are connected. The structure of carbon black develops into a complex entangled shape as the primary particles become smaller in size. Carbon black is characterized by its thermal history during synthesis (e.g. thermal history caused by thermal decomposition and combustion reactions of fuel oil, thermal decomposition and combustion reactions of raw materials, rapid cooling with cooling medium and reaction termination, etc.), collision frequency of primary particles. The degree of development of structure and agglomerate (secondary aggregation of structure) varies greatly depending on the difference in structure and agglomerate (secondary aggregation of structure).
　塩酸吸液量は、ＪＩＳ　Ｋ１４６９：２００３に従って測定することができる。具体的には、三角フラスコに入れたカーボンブラック５ｇに塩酸を少量ずつ加えながら振り混ぜ、一つの団塊状になるまでに要した塩酸の量を測定することで求められる。 The amount of hydrochloric acid absorbed can be measured according to JIS K1469:2003. Specifically, it is determined by adding hydrochloric acid little by little to 5 g of carbon black in an Erlenmeyer flask, shaking it, and measuring the amount of hydrochloric acid required to form a lump.
　本実施形態のカーボンブラックにおいて、塩酸吸液量は、上記効果がより顕著に得られる観点から、３９ｍＬ／５ｇ以上、４０ｍＬ／５ｇ以上、又は、４１ｍＬ／５ｇ以上であってよい。 In the carbon black of this embodiment, the amount of hydrochloric acid absorbed may be 39 mL/5 g or more, 40 mL/5 g or more, or 41 mL/5 g or more, from the viewpoint of obtaining the above effects more significantly.
　本実施形態のカーボンブラックにおいて、塩酸吸液量が著しく大きくなると、ストラクチャーの過度な発達によって後述のスラリー粘度が高くなる。このため、本実施形態のカーボンブラックの塩酸吸液量は、後述のスラリー粘度が１５００ｍＰａ・ｓ以下であることが好ましい。換言すると、本実施形態のカーボンブラックにおいて、塩酸吸液量の好ましい範囲の上限は、後述のスラリー粘度によって規定されてよい。 In the carbon black of this embodiment, when the amount of hydrochloric acid absorbed becomes significantly large, the slurry viscosity described below increases due to excessive structure development. For this reason, it is preferable that the amount of hydrochloric acid absorbed by the carbon black of this embodiment is such that the slurry viscosity described below is 1500 mPa·s or less. In other words, in the carbon black of this embodiment, the upper limit of the preferable range of hydrochloric acid absorption amount may be defined by the slurry viscosity described below.
　本実施形態のカーボンブラックにおいて、塩酸吸液量は、後述のスラリー粘度が１５００ｍＰａ・ｓ以下となりやすい観点から、例えば４９ｍＬ／５ｇ以下、又は４８ｍＬ／５ｇ以下であってよい。
　すなわち、本実施形態のカーボンブラックにおいて、塩酸吸液量は、例えば３９～４９ｍＬ／５ｇ、３９～４８ｍＬ／５ｇ、４０～４９ｍＬ／５ｇ、４０～４８ｍＬ／５ｇ、４１～４９ｍＬ／５ｇ又は４１～４８ｍＬ／５ｇであってもよい。 In the carbon black of this embodiment, the hydrochloric acid absorption amount may be, for example, 49 mL/5 g or less, or 48 mL/5 g or less, from the viewpoint that the slurry viscosity described below is likely to be 1500 mPa·s or less.
That is, in the carbon black of this embodiment, the hydrochloric acid absorption amount is, for example, 39 to 49 mL/5 g, 39 to 48 mL/5 g, 40 to 49 mL/5 g, 40 to 48 mL/5 g, 41 to 49 mL/5 g, or 41 to 48 mL. /5g.
　本実施形態のカーボンブラックは、スラリー粘度が４００ｍＰａ・ｓ以上１５００ｍＰａ・ｓ以下であることが好ましい。 The carbon black of this embodiment preferably has a slurry viscosity of 400 mPa·s or more and 1500 mPa·s or less.
　なお、本明細書中、スラリー粘度とは、Ｎ－メチル－２－ピロリドンを分散媒として、カーボンブラックを３質量％分散させたスラリーの粘度を示す。より具体的には、カーボンブラック３質量％と、分散媒であるＮ－メチル－２－ピロリドン９７質量％とを、自転公転式混合機（シンキー社製「あわとり練太郎ＡＲＶ－３１０」）により回転数２０００ｒｐｍで３０分間混練してスラリーを得て、このスラリーの２５℃における粘度を、粘弾性測定機（ＡｎｔｏｎＰａａｒ社製「ＭＣＲ１０２」、φ３０ｍｍ、角度３°のコーンプレート使用、ギャップ１ｍｍ）を用いてせん断速度０．０１ｓ－１から１００ｓ－１まで変化させて測定し、せん断速度１０ｓ－１における粘度を求める。このようにして測定された、２５℃、せん断速度１０ｓ－１における粘度を、スラリー粘度とする。 In this specification, the slurry viscosity refers to the viscosity of a slurry in which 3% by mass of carbon black is dispersed using N-methyl-2-pyrrolidone as a dispersion medium. More specifically, 3% by mass of carbon black and 97% by mass of N-methyl-2-pyrrolidone as a dispersion medium were mixed using a rotation-revolution mixer ("Awatori Rentaro ARV-310" manufactured by Shinky Co., Ltd.). A slurry was obtained by kneading at a rotational speed of 2000 rpm for 30 minutes, and the viscosity of this slurry at 25° C. was measured using a viscoelasticity measuring machine (“MCR102” manufactured by Anton Paar, φ30 mm, using a cone plate with an angle of 3°, gap 1 mm). The viscosity at a shear rate of 10 s -1 is determined by changing the shear rate from 0.01 s -1 to 100 s -1 . The viscosity measured in this manner at 25° C. and a shear rate of 10 s −1 is defined as the slurry viscosity.
　スラリー粘度は、剪断下におけるカーボンブラックの分散し易さと安定性の指標である。スラリー粘度が４００ｍＰａ・ｓ以上１５００ｍＰａ・ｓ以下のカーボンブラックを燃料電池用触媒用担体に用いると、燃料電池用触媒と電解質と溶媒とを混合した触媒ペーストが均一になり易いので、当該触媒ペーストを塗工して得られる電極触媒層中で、燃料電池用触媒が凝集粒子を形成し難い。このため、より優れた長期信頼性及び反応効率が得られやすくなる。 Slurry viscosity is an indicator of the dispersibility and stability of carbon black under shear. When carbon black with a slurry viscosity of 400 mPa・s or more and 1500 mPa・s or less is used as a carrier for a fuel cell catalyst, the catalyst paste, which is a mixture of a fuel cell catalyst, an electrolyte, and a solvent, tends to be uniform. In the electrode catalyst layer obtained by coating, the fuel cell catalyst is difficult to form aggregated particles. Therefore, it becomes easier to obtain better long-term reliability and reaction efficiency.
　本実施形態のカーボンブラックにおいて、スラリー粘度は、上記効果がより顕著に得られる観点から、４５０ｍＰａ・ｓ以上又は５００ｍＰａ・ｓ以上であってもよい。また、スラリー粘度は、上記効果がより顕著に得られる観点から、１４００ｍＰａ・ｓ以下、又は１３００ｍＰａ・ｓ以下であってもよい。
　すなわち、本実施形態のカーボンブラックにおいて、スラリー粘度は、例えば４００～１５００ｍＰａ・ｓ、４００～１４００ｍＰａ・ｓ、４００～１３００ｍＰａ・ｓ、４５０～１５００ｍＰａ・ｓ、４５０～１４００ｍＰａ・ｓ、４５０～１３００ｍＰａ・ｓ、５００～１５００ｍＰａ・ｓ、５００～１４００ｍＰａ・ｓ又は５００～１３００ｍＰａ・ｓであってもよい。 In the carbon black of this embodiment, the slurry viscosity may be 450 mPa·s or more or 500 mPa·s or more from the viewpoint of obtaining the above effects more significantly. Moreover, the slurry viscosity may be 1400 mPa·s or less, or 1300 mPa·s or less from the viewpoint of obtaining the above effects more significantly.
That is, in the carbon black of this embodiment, the slurry viscosity is, for example, 400 to 1500 mPa·s, 400 to 1400 mPa·s, 400 to 1300 mPa·s, 450 to 1500 mPa·s, 450 to 1400 mPa·s, 450 to 1300 mPa·s. , 500 to 1500 mPa·s, 500 to 1400 mPa·s or 500 to 1300 mPa·s.
　なお、カーボンブラックのスラリー粘度は、カーボンブラックの平均一次粒子径、カーボンブラックの表面性状、カーボンブラックのストラクチャーの形状等によって適宜調整されてよい。 Note that the slurry viscosity of carbon black may be adjusted as appropriate depending on the average primary particle diameter of carbon black, the surface properties of carbon black, the shape of the structure of carbon black, etc.
　本実施形態のカーボンブラックのＤＢＰ吸収量は、例えば、２００ｍＬ／１００ｇ以上、２１０ｍＬ／１００ｇ以上、又は、２２０ｍＬ／１００ｇ以上であってよい。また、本実施形態のカーボンブラックのＤＢＰ吸収量は、例えば、４００ｍＬ／１００ｇ以下、３９０ｍＬ／１００ｇ以下、又は、３８０ｍＬ／１００ｇ以下であってよい。
　すなわち、本実施形態のカーボンブラックのＤＢＰ吸収量は、例えば２００～４００ｍＬ／１００ｇ、２００～３９０ｍＬ／１００ｇ、２００～３８０ｍＬ／１００ｇ、２１０～４００ｍＬ／１００ｇ、２１０～３９０ｍＬ／１００ｇ、２１０～３８０ｍＬ／１００ｇ、２２０～４００ｍＬ／１００ｇ、２２０～３９０ｍＬ／１００ｇ又は２２０～３８０ｍＬ／１００ｇであってもよい。 The DBP absorption amount of the carbon black of this embodiment may be, for example, 200 mL/100 g or more, 210 mL/100 g or more, or 220 mL/100 g or more. Further, the DBP absorption amount of the carbon black of this embodiment may be, for example, 400 mL/100 g or less, 390 mL/100 g or less, or 380 mL/100 g or less.
That is, the DBP absorption amount of the carbon black of this embodiment is, for example, 200 to 400 mL/100 g, 200 to 390 mL/100 g, 200 to 380 mL/100 g, 210 to 400 mL/100 g, 210 to 390 mL/100 g, 210 to 380 mL/100 g. , 220 to 400 mL/100 g, 220 to 390 mL/100 g, or 220 to 380 mL/100 g.
　ＤＢＰ吸収量とは、カーボンブラックの粒子表面及びストラクチャーが作る空隙にジブチルフタレート（ＤＢＰ）を吸収する能力を評価する指標である。本明細書中、ＤＢＰ吸収量は、ＪＩＳ　Ｋ６２２１のＢ法に記載の方法により測定された値を、下記式（ａ）により、ＪＩＳ　Ｋ６２１７－４：２００８相当の値に換算した値を示す。
　ＤＢＰ吸収量＝（Ａ－１０．９７４）／０．７８３３　…（ａ）
［式中、Ａは、ＪＩＳ　Ｋ６２２１に記載の方法により測定されたＤＢＰ吸収量の相当値を示す。］ The DBP absorption amount is an index for evaluating the ability to absorb dibutyl phthalate (DBP) in the voids formed by the particle surface and structure of carbon black. In the present specification, the DBP absorption amount indicates a value obtained by converting a value measured by the method described in JIS K6221 Method B into a value equivalent to JIS K6217-4:2008 using the following formula (a).
DBP absorption amount = (A-10.974)/0.7833...(a)
[Wherein, A represents the equivalent value of DBP absorption measured by the method described in JIS K6221. ]
　ストラクチャーの発達したカーボンブラックでは、一次粒子が融着してできるネック部や粒子間で形成される空隙が多くなるためＤＢＰ吸収量が多くなる。ＤＢＰ吸収量が少なすぎると、燃料電池用触媒と電解質と溶媒とを混合した触媒ペーストの粘度が低くなり過ぎて、混合による剪断力がかかり難くなり、良好な分散性が得られ難くなる場合がある。一方、ＤＢＰ吸収量が多すぎると、上記触媒ペーストの粘度が高くなり過ぎて、良好な分散性が得られ難くなる場合がある。すなわち、ＤＢＰ吸収量が上記好適な範囲であると、適度な粘度を有する均一な触媒ペーストがより得られやすくなり、凝集粒子の少ない電極触媒層がより得られやすくなり、長期信頼性及び反応効率がより高くなる傾向がある。 Carbon black with a developed structure has more necks formed by fusion of primary particles and more voids formed between particles, so the amount of DBP absorbed increases. If the DBP absorption amount is too small, the viscosity of the catalyst paste made by mixing the fuel cell catalyst, electrolyte, and solvent will become too low, making it difficult to apply shearing force due to mixing, and making it difficult to obtain good dispersibility. be. On the other hand, if the amount of DBP absorbed is too large, the viscosity of the catalyst paste may become too high, making it difficult to obtain good dispersibility. In other words, when the DBP absorption amount is within the above-mentioned preferred range, it becomes easier to obtain a uniform catalyst paste with an appropriate viscosity, it becomes easier to obtain an electrode catalyst layer with less aggregated particles, and the long-term reliability and reaction efficiency are improved. tends to be higher.
　また、適度にストラクチャーが発達したカーボンブラックを燃料電池用触媒用担体に用いると、電極触媒層内に、水素ガスやプロトンが効率良く拡散する空隙が形成される。このため、良好な燃料電池特性が得られやすくなる。この観点からも、ＤＢＰ吸収量は上記範囲であることが好ましい。 Furthermore, when carbon black with a suitably developed structure is used as a fuel cell catalyst carrier, voids are formed in the electrode catalyst layer through which hydrogen gas and protons can efficiently diffuse. Therefore, it becomes easier to obtain good fuel cell characteristics. Also from this point of view, the DBP absorption amount is preferably within the above range.
　本実施形態のカーボンブラックの平均一次粒子径は、例えば、３０ｎｍ未満、２９ｎｍ未満、２８ｎｍ未満、２７ｎｍ未満、２６ｎｍ未満、又は、２５ｎｍ未満であってよい。また、本実施形態のカーボンブラックの平均一次粒子径は、例えば１０ｎｍ以上であってよい。
　本発明者らの知見によれば、上述の比（Ｓ２／Ｓ１）を満たすカーボンブラックでは、比表面積が同程度で平均一次粒子径が異なる２種を比較したところ、小粒径のカーボンブラックのほうが、カーボンブラック上に形成される金属粒子の粒径が小さくなる。これは、大粒径のカーボンブラックでは表面の多孔質化によって比表面積が高くなる一方、小粒径のカーボンブラックでは比較的表面が滑らかであっても高比表面積を達成できるため、分散媒と接する表面が多くなり、金属粒子を形成する反応場が増えるため、と考えられる。 The average primary particle size of the carbon black of this embodiment may be, for example, less than 30 nm, less than 29 nm, less than 28 nm, less than 27 nm, less than 26 nm, or less than 25 nm. Further, the average primary particle diameter of the carbon black of this embodiment may be, for example, 10 nm or more.
According to the findings of the present inventors, when comparing two types of carbon black that satisfy the above ratio (S 2 /S 1 ) with similar specific surface areas but different average primary particle sizes, it was found that carbon black with a small particle size In the case of carbon black, the particle size of metal particles formed on the carbon black is smaller. This is because carbon black with a large particle size has a high specific surface area due to a porous surface, while carbon black with a small particle size can achieve a high specific surface area even if the surface is relatively smooth. This is thought to be because the number of surfaces in contact increases, and the number of reaction fields for forming metal particles increases.
　従来、燃料電池触媒担体に用いられるカーボンブラックは、平均一次粒子径が小さい（例えば３０ｎｍ未満である）と平滑な電極触媒層を得ることが困難であったが、本実施形態のカーボンブラックは、上述の比（Ｓ２／Ｓ１）を満たすため、平均一次粒子径が小さい（例えば３０ｎｍ未満の）場合でも平滑な電極触媒層を得ることができて、それを用いた燃料電池は高い出力電圧と長寿命を発揮することができる。 Conventionally, with carbon black used for fuel cell catalyst carriers, it was difficult to obtain a smooth electrode catalyst layer when the average primary particle size was small (for example, less than 30 nm), but the carbon black of this embodiment Since the above-mentioned ratio (S 2 /S 1 ) is satisfied, a smooth electrode catalyst layer can be obtained even when the average primary particle diameter is small (for example, less than 30 nm), and a fuel cell using it can have a high output voltage. and can exhibit long life.
　カーボンブラックの平均一次粒子径は、透過型電子顕微鏡（ＴＥＭ）の５万倍拡大画像から無作為に選択した１００個以上のカーボンブラックの一次粒子径を測り、平均値を算出して求めることができる。カーボンブラックの一次粒子はアスペクト比が小さく真球に近い形状をしているが、完全な真球ではない。そこで、本実施形態では、ＴＥＭ画像における一次粒子の外周２点を結ぶ線分のうちで最大のものをカーボンブラックの一次粒子径とする。 The average primary particle size of carbon black can be determined by measuring the primary particle size of 100 or more carbon black particles randomly selected from a 50,000x magnified image using a transmission electron microscope (TEM) and calculating the average value. can. Although the primary particles of carbon black have a small aspect ratio and a shape close to a true sphere, they are not completely true spheres. Therefore, in this embodiment, the largest line segment connecting two points on the outer periphery of the primary particle in the TEM image is defined as the primary particle diameter of carbon black.
　本実施形態のカーボンブラックの灰分は、例えば０．０５質量％以下、０．０３質量％以下、又は、０．０２質量％以下であってよい。灰分はＪＩＳ　Ｋ１４６９：２００３に従って測定することができ、例えば、カーボンブラックを乾式サイクロンなどの装置で分級することによって低減できる。 The ash content of the carbon black of this embodiment may be, for example, 0.05% by mass or less, 0.03% by mass or less, or 0.02% by mass or less. The ash content can be measured according to JIS K1469:2003, and can be reduced, for example, by classifying carbon black with a device such as a dry cyclone.
　本実施形態のカーボンブラックの硫黄分は、例えば５０質量ｐｐｍ以下であってよい。カーボンブラックにおける硫黄分は、カーボンブラック表面に硫酸基などの酸性官能基として存在している。硫黄分が５０質量ｐｐｍ以下であると、電池内部の電気化学的な反応によるＳＯｘ等のガスの発生が抑制され、当該ガスに起因する燃料電池性能の劣化が顕著に抑制される。カーボンブラックの硫黄分は、カーボンブラックを酸素気流中で燃焼させ発生する燃焼ガスを過酸化水素水に吸収させ、それをイオンクロマトグラフィーで測定することで算出できる。 The sulfur content of the carbon black of this embodiment may be, for example, 50 mass ppm or less. The sulfur content in carbon black exists as acidic functional groups such as sulfuric acid groups on the surface of carbon black. When the sulfur content is 50 mass ppm or less, generation of gases such as SOx due to electrochemical reactions inside the battery is suppressed, and deterioration of fuel cell performance due to the gases is significantly suppressed. The sulfur content of carbon black can be calculated by burning carbon black in an oxygen stream, absorbing the generated combustion gas into a hydrogen peroxide solution, and measuring it using ion chromatography.
　本実施形態のカーボンブラックの製造方法は特に限定されるものではなく、例えば、炭化水素などの原料を反応炉の上流部に設置されたノズルから供給し、熱分解反応及び／又は燃焼反応によりカーボンブラックを生成し、反応炉の下流部に直結されたバグフィルターから捕集することで、カーボンブラックを得ることができる。 The method for producing carbon black of this embodiment is not particularly limited. For example, raw materials such as hydrocarbons are supplied from a nozzle installed upstream of a reactor, and carbon black is produced by a thermal decomposition reaction and/or a combustion reaction. Carbon black can be obtained by generating black and collecting it from a bag filter directly connected downstream of the reactor.
　使用する原料は特に限定されるものではなく、アセチレン、メタン、エタン、プロパン、エチレン、プロピレン、ブタジエンなどのガス状炭化水素や、トルエン、ベンゼン、キシレン、ガソリン、灯油、軽油、重油などのオイル状炭化水素を使用することができる。中でも不純物が少ないアセチレンを使用することが好ましい。アセチレンは他の原料よりも分解熱が大きく、反応炉内の温度を高くすることができるため、カーボンブラックの核生成が付加反応による粒子成長よりも優勢となり、カーボンブラックの一次粒子径を小さくすることができる。また、本発明者らは、カーボンブラックの表面性状を制御するために鋭意検討を行った結果、複数の原料を使用し、かつ、原料を加熱してから反応炉へ供給することが有効であることを見出した。従来の製法では反応炉の高温部を経由して生成したカーボンブラックと、低温部を経由して生成したカーボンブラックが混在し、特性上のばらつきも大きかったが、複数の原料を使用することにより反応炉内の温度が均一になり、経由する熱分解、燃焼の反応履歴も均一になるため、カーボンブラック表面に存在する多環芳香族炭化水素の割合が低下したと考えられる。また、原料を加熱することで複数原料の混合が促進され、より均一な温度場を形成することができたと考えられる。複数の原料は反応炉へ供給する前に混合することが好ましい。オイル状炭化水素を用いる場合には加熱によりガス化して供給することが好ましい。加熱の方法は特に限定されるものではなく、例えばタンク、輸送配管を熱媒との熱交換により加熱することができる。 The raw materials used are not particularly limited, and include gaseous hydrocarbons such as acetylene, methane, ethane, propane, ethylene, propylene, butadiene, and oils such as toluene, benzene, xylene, gasoline, kerosene, light oil, and heavy oil. Hydrocarbons can be used. Among them, it is preferable to use acetylene, which has few impurities. Acetylene has a larger heat of decomposition than other raw materials, and the temperature inside the reactor can be raised, so carbon black nucleation dominates particle growth due to addition reactions, reducing the primary particle size of carbon black. be able to. In addition, as a result of intensive studies to control the surface properties of carbon black, the present inventors found that it is effective to use multiple raw materials and heat the raw materials before supplying them to the reactor. I discovered that. In the conventional manufacturing method, carbon black produced through the high-temperature section of the reactor and carbon black produced via the low-temperature section coexist, resulting in large variations in properties, but by using multiple raw materials, It is thought that the proportion of polycyclic aromatic hydrocarbons present on the surface of carbon black decreased because the temperature in the reactor became uniform and the reaction history of thermal decomposition and combustion became uniform. In addition, it is thought that heating the raw materials promoted the mixing of multiple raw materials, making it possible to form a more uniform temperature field. Preferably, the plurality of raw materials are mixed before being supplied to the reactor. When using oily hydrocarbons, it is preferable to gasify them by heating and then supply them. The heating method is not particularly limited, and for example, a tank or transport piping can be heated by heat exchange with a heating medium.
　また、炭素源となる原料とは別に、酸素、水素、窒素、スチームなどを反応炉に供給することが好ましい。これらの原料以外のガスは反応炉内のガス攪拌を促進し、原料から生成したカーボンブラックの一次粒子同士が衝突、融着する頻度を高めるため、原料以外のガスを使用することで、カーボンブラックのストラクチャーが発達し、ＤＢＰ吸収量が多くなる傾向がある。原料以外のガスとしては、酸素を使用することが好ましい。酸素を使用すると原料の一部が燃焼して反応炉内の温度が高くなり、小粒径、高比表面積のカーボンブラックが得られやすくなる。原料以外のガスとして、複数のガスを使用することもできる。原料以外のガスの供給箇所は反応炉の上流部が好ましく、原料とは別のノズルから供給することが好ましい。これにより同じく上流部から供給される原料の攪拌が効率的に起こり、ストラクチャーが発達しやすくなる。 Additionally, it is preferable to supply oxygen, hydrogen, nitrogen, steam, etc. to the reactor separately from the raw material serving as the carbon source. These gases other than raw materials promote gas agitation in the reactor and increase the frequency of collision and fusion of primary particles of carbon black produced from raw materials. By using gases other than raw materials, carbon black structure develops, and the amount of DBP absorbed tends to increase. It is preferable to use oxygen as the gas other than the raw material. When oxygen is used, part of the raw material is combusted and the temperature inside the reactor increases, making it easier to obtain carbon black with a small particle size and a high specific surface area. A plurality of gases can also be used as the gas other than the raw material. The gas other than the raw material is preferably supplied to the upstream part of the reactor, and is preferably supplied from a different nozzle from that for the raw material. As a result, the raw materials supplied from the upstream portion are efficiently stirred, and the structure is facilitated to develop.
　従来のカーボンブラック製造では、原料の熱分解、燃焼反応の停止のために反応炉の下流部から水などの冷却用媒体を送入する場合があるが、ストラクチャー発達の効果は見られず、一方で表面性状に影響を与えるおそれがあるため、本実施形態では反応炉の下流部から冷却用媒体を送入しないことが好ましい。 In conventional carbon black production, a cooling medium such as water is sometimes introduced from the downstream part of the reactor to thermally decompose the raw material and stop the combustion reaction, but no effect on structure development has been observed. In this embodiment, it is preferable not to introduce a cooling medium from the downstream part of the reactor, since this may affect the surface properties.
＜燃料電池用触媒＞
　本実施形態の燃料電池用触媒は、燃料電池用触媒用担体（カーボンブラック）の表面に、白金粒子及び白金合金粒子からなる群より選択される少なくとも一種の金属粒子を担持させたものである。金属粒子は、担体表面に強く担持されていることが好ましい。 <Fuel cell catalyst>
The fuel cell catalyst of this embodiment has at least one metal particle selected from the group consisting of platinum particles and platinum alloy particles supported on the surface of a fuel cell catalyst carrier (carbon black). Preferably, the metal particles are strongly supported on the surface of the carrier.
　金属粒子の平均粒径は、例えば２ｎｍ以上であってよい。平均粒径が２ｎｍ以上であると、電位変動時の溶解、腐食等が抑制される。金属粒子の平均粒径は、例えば５ｎｍ以下であってよい。平均粒径が５ｎｍ以下であると、活性を有する表面積が十分に確保され、より優れた燃料電池特性が得られやすい。金属粒子の粒径を、透過型電子顕微鏡での観察により、金属粒子の外周２点を結ぶ線分のうちで最大となる線分の長さとする。金属粒子の平均粒径は、１０００個の金属粒子の粒径を測定してその平均値を算出することで求めることができる。 The average particle size of the metal particles may be, for example, 2 nm or more. When the average particle size is 2 nm or more, dissolution, corrosion, etc. during potential fluctuations are suppressed. The average particle size of the metal particles may be, for example, 5 nm or less. When the average particle size is 5 nm or less, a sufficient active surface area is ensured, and better fuel cell characteristics are likely to be obtained. The particle size of the metal particles is determined by the length of the longest line segment connecting two points on the outer periphery of the metal particles, as determined by observation with a transmission electron microscope. The average particle size of metal particles can be determined by measuring the particle size of 1000 metal particles and calculating the average value.
　白金粒子は、白金で構成される粒子である。白金合金粒子は、白金と他の金属（以下、合金形成金属）との合金で構成される粒子である。 Platinum particles are particles composed of platinum. Platinum alloy particles are particles composed of an alloy of platinum and other metals (hereinafter referred to as alloy forming metals).
　合金形成金属としては、パラジウム、ロジウム、イリジウム、ルテニウム、鉄、チタン、ニッケル、コバルト、金、銀、銅、クロム、マンガン、モリブデン、タングステン、アルミニウム、ケイ素、レニウム、亜鉛、スズ等が挙げられる。これらのうち、直接メタノール型燃料電池用触媒の場合は、一酸化炭素被毒防止に有効であるので、白金－ルテニウム合金が好ましい。 Examples of alloy forming metals include palladium, rhodium, iridium, ruthenium, iron, titanium, nickel, cobalt, gold, silver, copper, chromium, manganese, molybdenum, tungsten, aluminum, silicon, rhenium, zinc, tin, and the like. Among these, in the case of direct methanol fuel cell catalysts, platinum-ruthenium alloys are preferred because they are effective in preventing carbon monoxide poisoning.
　合金の組成は特に限定されないが、例えば、白金が３０～９０質量％、合金形成金属が１０～７０質量％であってよい。 The composition of the alloy is not particularly limited, but may be, for example, 30 to 90% by mass of platinum and 10 to 70% by mass of alloy forming metal.
　燃料電池用触媒における金属粒子の担持量は、カーボンブラック１００質量部に対して、例えば５質量部以上８０質量部以下であってよい。 The amount of metal particles supported in the fuel cell catalyst may be, for example, 5 parts by mass or more and 80 parts by mass or less, based on 100 parts by mass of carbon black.
　カーボンブラックへの金属粒子の担持方法は特に制限されず、例えば、以下の方法であってよい。カーボンブラックを水に懸濁させてスラリーとし、これに金属源を加えて混合液Ａとし、これに金属に対して１０倍当量の水素化ホウ素ナトリウムを添加し、カーボンブラックの表面に金属粒子を析出させた後、濾過、洗浄、乾燥することによって、燃料電池用触媒が得られる。 The method for supporting metal particles on carbon black is not particularly limited, and may be, for example, the following method. Carbon black is suspended in water to form a slurry, a metal source is added to this to form a mixed solution A, and sodium borohydride is added in an amount equivalent to 10 times the amount of the metal to form metal particles on the surface of the carbon black. After precipitation, a fuel cell catalyst is obtained by filtering, washing, and drying.
　金属源のうち、白金源としては、ヘキサクロロ白金水溶液、ヘキサヒドロキソ白金水溶液、ジニトロジアンミン白金水溶液等が挙げられる。 Among the metal sources, platinum sources include hexachloroplatinum aqueous solution, hexahydroxoplatinum aqueous solution, dinitrodiammine platinum aqueous solution, and the like.
　金属源のうち、合金形成金属源としては、例えば、三塩化ルテニウム（ＩＩＩ）水溶液等が挙げられる。 Among the metal sources, examples of the alloy-forming metal source include a ruthenium (III) trichloride aqueous solution.
　金属粒子の析出に際しては、適宜、水酸化ナトリウム水溶液等のｐＨ調整剤を添加してもよい。 When depositing metal particles, a pH adjuster such as an aqueous sodium hydroxide solution may be added as appropriate.
　燃料電池用触媒は、カーボンブラックへの金属粒子の担持後、アニール処理を行ってから、燃料電池に供してもよい。アニール処理は、例えば、アルゴンガス、窒素ガス等の不活性雰囲気、又は、水素ガス等の還元雰囲気中、８００～１０００℃に加熱することで実施することができる。 The fuel cell catalyst may be subjected to an annealing treatment after supporting metal particles on carbon black, and then used in a fuel cell. The annealing treatment can be performed by heating to 800 to 1000° C., for example, in an inert atmosphere such as argon gas or nitrogen gas, or a reducing atmosphere such as hydrogen gas.
　本実施形態の燃料電池用触媒の評価は、例えば、固体高分子型燃料電池の場合、以下のようにして行うことができる。燃料電池用触媒をナフィオン溶液と混合し、アルコールを加えてペースト状にしたものをカーボンペーパーの片面に塗布し、乾燥して、電極触媒層（評価用電極）を形成する。次いで、Ｎａｆｉｏｎ膜（パーフルオロスルホン酸電解質膜）の一方の面に評価用電極を接するように重ね合わせ、もう一方の面に既知の電極を接するように重ね合わせ、１３０℃のホットプレスで熱圧着させて、電解質膜－電極接合体（ＭＥＡ）を得る。ＭＥＡをセパレータ、続いて集電板で挟み込めば単セルが完成し、電子負荷装置、ガス供給装置を接続すれば燃料電池の評価を行うことができる。また、市販されている燃料電池単セル評価装置を用いることで、上記評価をより簡便に行うこともできる。 For example, in the case of a polymer electrolyte fuel cell, the evaluation of the fuel cell catalyst of this embodiment can be performed as follows. A fuel cell catalyst is mixed with a Nafion solution and alcohol is added to form a paste, which is applied to one side of carbon paper and dried to form an electrode catalyst layer (electrode for evaluation). Next, an evaluation electrode was placed on one side of the Nafion membrane (perfluorosulfonic acid electrolyte membrane), and a known electrode was placed on the other side, and thermocompression bonded using a hot press at 130°C. In this way, an electrolyte membrane-electrode assembly (MEA) is obtained. A single cell is completed by sandwiching the MEA between a separator and a current collector plate, and the fuel cell can be evaluated by connecting an electronic load device and a gas supply device. Moreover, the above evaluation can be performed more easily by using a commercially available fuel cell single cell evaluation device.
＜電極触媒層＞
　本実施形態の電極触媒層は、上記燃料電池用触媒と電解質とを含有する。 <Electrode catalyst layer>
The electrode catalyst layer of this embodiment contains the above fuel cell catalyst and electrolyte.
　電解質は特に限定されず、公知の燃料電池に使用される電解質を特に制限なく使用できる。電解質としては、パーフルオロスルホン酸ポリマーが好適に用いられ、例えば、Ｎａｆｉｏｎ（Ｄｕｐｏｎｔ社製）、Ａｃｉｐｌｅｘ（旭化成社製）、Ｆｌｅｍｉｏｎ（旭硝子社製）等が挙げられる。 The electrolyte is not particularly limited, and electrolytes used in known fuel cells can be used without particular limitation. As the electrolyte, perfluorosulfonic acid polymers are preferably used, and examples thereof include Nafion (manufactured by Dupont), Aciplex (manufactured by Asahi Kasei), Flemion (manufactured by Asahi Glass), and the like.
　電極触媒層の厚さは、例えば５μｍ以上、又は１０μｍ以上であってよい。また、電極触媒層の厚さは、例えば５０μｍ以下、４０μｍ以下、又は３０μｍ以下であってよい。
　すなわち、電極触媒層の厚さは、例えば５～５０μｍ、５～４０μｍ、５～３０μｍ、１０～５０μｍ、１０～４０μｍ又は１０～３０μｍであってもよい。 The thickness of the electrode catalyst layer may be, for example, 5 μm or more, or 10 μm or more. Further, the thickness of the electrode catalyst layer may be, for example, 50 μm or less, 40 μm or less, or 30 μm or less.
That is, the thickness of the electrode catalyst layer may be, for example, 5 to 50 μm, 5 to 40 μm, 5 to 30 μm, 10 to 50 μm, 10 to 40 μm, or 10 to 30 μm.
＜燃料電池＞
　本実施形態の燃料電池は、上述の本実施形態の電極触媒層を備える。 <Fuel cell>
The fuel cell of this embodiment includes the electrode catalyst layer of this embodiment described above.
　本実施形態において、上記電極触媒層以外の構成は特に限定されず、公知の燃料電池と同様の構成であってよい。 In this embodiment, the structure other than the electrode catalyst layer is not particularly limited, and may be the same structure as a known fuel cell.
　本実施形態の燃料電池は、例えば、第一のセパレータと、アノード電極触媒層と、電解質膜と、カソード電極触媒層と、第二のセパレータと、を備えるものであってもよく、第一のセパレータと、第一のガス拡散層と、アノード電極触媒層と、電解質膜と、カソード電極触媒層と、第二のガス拡散層と、第二のセパレータと、を備えるものであってもよい。 The fuel cell of this embodiment may include, for example, a first separator, an anode electrode catalyst layer, an electrolyte membrane, a cathode electrode catalyst layer, and a second separator. It may include a separator, a first gas diffusion layer, an anode electrode catalyst layer, an electrolyte membrane, a cathode electrode catalyst layer, a second gas diffusion layer, and a second separator.
　本実施形態の燃料電池は、アノード電極触媒層及びカソード電極触媒層のうち、一方が上述の本実施形態の電極触媒層であればよい。 In the fuel cell of this embodiment, one of the anode electrode catalyst layer and the cathode electrode catalyst layer may be the electrode catalyst layer of this embodiment described above.
　第一のセパレータ及び第二のセパレータは、ガス流路を備えるセパレータであればよい。第一のセパレータ及び第二のセパレータは、公知の燃料電池に使用されるセパレータであってよい。第一のセパレータ及び第二のセパレータは、例えば、ステンレス鋼、アルミ合金、カーボン等の材質で構成されたものであってよい。 The first separator and the second separator may be any separator provided with a gas flow path. The first separator and the second separator may be separators used in known fuel cells. The first separator and the second separator may be made of, for example, stainless steel, aluminum alloy, carbon, or the like.
　第一のガス拡散層及び第二のガス拡散層は、公知の燃料電池に使用されるガス拡散層であってよい。第一のガス拡散層及び第二のガス拡散層は、例えば、基材（例えば、炭素繊維のペーパー、織布、不織布等）の表面にコーティング層（例えば、カーボン材料及び撥水材からなるコーティング層）を設けた層であってよい。 The first gas diffusion layer and the second gas diffusion layer may be gas diffusion layers used in known fuel cells. The first gas diffusion layer and the second gas diffusion layer are, for example, a coating layer (for example, a coating made of a carbon material and a water repellent material) on the surface of a base material (for example, carbon fiber paper, woven fabric, nonwoven fabric, etc.). layer) may be provided.
　アノード電極触媒層及びカソード電極触媒層は、一方が上述の本実施形態の電極触媒層、他方がそれ以外の電極触媒層であってよい。また、アノード電極触媒層及びカソード電極触媒層は、両方が上述の本実施形態の電極触媒層であってもよい。本実施形態の電極触媒層以外の電極触媒層は、公知の燃料電池に使用される電極触媒層であってよい。 One of the anode electrode catalyst layer and the cathode electrode catalyst layer may be the electrode catalyst layer of the above-described present embodiment, and the other may be another electrode catalyst layer. Moreover, both the anode electrode catalyst layer and the cathode electrode catalyst layer may be the electrode catalyst layers of the above-described present embodiment. Electrode catalyst layers other than the electrode catalyst layer of this embodiment may be electrode catalyst layers used in known fuel cells.
　電解質膜は、公知の燃料電池に使用される電解質膜であってよい。電解質膜は、パーフルオロスルホン酸ポリマーが好適に用いられ、例えば、Ｎａｆｉｏｎ（Ｄｕｐｏｎｔ社製）、Ａｃｉｐｌｅｘ（旭化成社製）、Ｆｌｅｍｉｏｎ（旭硝子社製）等であってよい。 The electrolyte membrane may be an electrolyte membrane used in known fuel cells. A perfluorosulfonic acid polymer is preferably used for the electrolyte membrane, and may be, for example, Nafion (manufactured by Dupont), Aciplex (manufactured by Asahi Kasei), Flemion (manufactured by Asahi Glass), or the like.
　以上、本発明の好適な実施形態について説明したが、本発明は上記実施形態に限定されるものではない。 Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments.
　以下、実施例によって本発明を更に詳細に説明するが、本発明はこれらの実施例に限定されるものではない。 Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.
（実施例１）
＜カーボンブラックの製造＞
　カーボンブラック反応炉（炉長６ｍ、炉直径０．６５ｍ）の上流部に設置されたノズルから原料であるアセチレンを１２Ｎｍ３／ｈ、トルエンを３２ｋｇ／ｈ、原料以外のガスとして酸素を２１Ｎｍ３／ｈ供給してカーボンブラックを製造し、反応炉の下流部に設置したバグフィルターで捕集した。その後、乾式サイクロン装置、鉄除去用磁石を通過させてタンクに回収した。なお、アセチレン、トルエン、酸素は１１５℃に加熱してから反応炉へ供給した。得られたカーボンブラックについて、以下の物性を測定した。評価結果を表１及び表２に示す。 (Example 1)
<Manufacture of carbon black>
From a nozzle installed at the upstream part of a carbon black reactor (furnace length: 6 m, furnace diameter: 0.65 m), acetylene as a raw material is fed at a rate of 12 Nm 3 /h, toluene at a rate of 32 kg/h, and oxygen as a gas other than the raw material at a rate of 21 Nm 3 /h . h to produce carbon black, which was collected by a bag filter installed downstream of the reactor. Thereafter, it was passed through a dry cyclone device and a magnet for iron removal and collected into a tank. Note that acetylene, toluene, and oxygen were heated to 115° C. and then supplied to the reactor. The following physical properties of the obtained carbon black were measured. The evaluation results are shown in Tables 1 and 2.
（１）比表面積
　ＪＩＳ　Ｋ６２１７－２：２０１７のＡ法流通法（熱伝導度測定法）に従い測定した。
（２）昇温脱離ガス分析法による比（Ｓ２／Ｓ１）
　カーボンブラックをサンプルカップに２～５ｍｇ秤量し、熱分解装置（フロンティアラボ社製「ＰＹ－２０２０ｉＤ」）を設置したガスクロマトグラフ質量分析計（島津製作所社製「ＱＰ－２０１０」）にセットした。大気圧Ｈｅフロー中で５０℃で５分間保持した後、８０℃／ｍｉｎで８００℃まで昇温し、脱離した成分の質量分析を下記の条件で検出した。得られたｍ／ｚ１２８とｍ／ｚ５７のピーク面積の比をとることで、ピーク面積比（Ｓ２／Ｓ１）を算出した。なお、図１は、実施例１のカーボンブラックの、昇温脱離ガス分析法により検出されるｍ／ｚ５７及びｍ／ｚ１２８のチャートを示す図である。
　　カラム：　フロンティアラボ社製Ｕｌｔｒａ　ＡＬＬＯＹ－ＤＴＭ　長さ２．５ｍ、０．１５ｍ　ｍＩ．Ｄ、０．４７ｍｍＯ．Ｄ
　　ガスクロマト導入温度：　３００℃
　　カラム温度：　３００℃　８０分保持
　　スプリット比：　３０：１
　　カラム流量：　１．０ｍＬ／ｍｉｎ
　　イオン化法：　ＥＩ
　　質量範囲：ｍ／ｚ＝１０～２００
（３）塩酸吸液量
　ＪＩＳ　Ｋ１４６９－４：２００３に従い測定した。
（４）ＤＢＰ吸収量
　ＪＩＳ　Ｋ６２２１のＢ法に記載の方法により測定した値を、上記式（ａ）により、ＪＩＳ　Ｋ６２１７－４：２００８相当の値に換算した。
（５）平均一次粒子径
　透過型電子顕微鏡の５万倍画像より、無作為に選択した１００個以上のカーボンブラック一次粒子径を測り、平均値を算出した。
（６）灰分
　ＪＩＳ　Ｋ１４６９：２００３に従い測定した。
（７）鉄の含有量
　ＪＩＳ　Ｋ０１１６：２０１４に従い酸分解法にて前処理し、高周波誘導結合プラズマ質量分析法にて測定した。
（８）スラリー粘度の評価
　カーボンブラック３質量部と、分散媒としてＮ－メチル－２－ピロリドン（関東化学社製）９７質量部を、自転公転式混合機（シンキー社製「あわとり練太郎ＡＲＶ－３１０」）回転数２０００ｒｐｍで３０分間混練し、カーボンブラックスラリーを作製した。このスラリーの２５℃における粘度を粘弾性測定機（ＡｎｔｏｎＰａａｒ社製「ＭＣＲ１０２」、φ３０ｍｍ、角度３°のコーンプレート使用、ギャップ１ｍｍ）で評価した。せん断速度は０．０１ｓ－１から１００ｓ－１へ変化させて測定し、せん断速度１０ｓ－１における粘度を求めた。測定結果を表２に示す。
（９）硫黄の含有量
　カーボンブラックの試料１ｇを磁性ボートに精密にはかり取り、１３００℃に昇温した燃焼吸収装置の反応管に挿入した。吸収液（過酸化水素水３．５ｍｌを純水で希釈し１Ｌとする）を入れた吸収瓶を接続し、酸素ガスを流し、燃焼ガスを吸収瓶に通した。得られた吸収液をイオンクロマトグラフィー分析装置に導入し、硫酸イオンのピーク面積を測定し、予め硫酸イオン標準溶液から作製した検量線を元に、試料中の硫黄の含有率を算出した。 (1) Specific surface area Measured according to JIS K6217-2:2017 method A distribution method (thermal conductivity measurement method).
(2) Ratio (S 2 /S 1 ) determined by temperature programmed desorption gas analysis method
2 to 5 mg of carbon black was weighed into a sample cup and set in a gas chromatograph mass spectrometer ("QP-2010" manufactured by Shimadzu Corporation) equipped with a pyrolysis device ("PY-2020iD" manufactured by Frontier Lab). After being held at 50°C for 5 minutes in an atmospheric pressure He flow, the temperature was raised to 800°C at a rate of 80°C/min, and the desorbed components were detected by mass spectrometry under the following conditions. The peak area ratio (S 2 /S 1 ) was calculated by taking the ratio of the obtained peak areas of m/z 128 and m/z 57. Note that FIG. 1 is a diagram showing a chart of m/z 57 and m/z 128 detected by temperature-programmed desorption gas analysis of the carbon black of Example 1.
Column: Ultra ALLOY-DTM manufactured by Frontier Lab, length 2.5 m, 0.15 m mI. D, 0.47mmO. D
Gas chromatography introduction temperature: 300℃
Column temperature: 300℃ held for 80 minutes Split ratio: 30:1
Column flow rate: 1.0mL/min
Ionization method: EI
Mass range: m/z=10-200
(3) Hydrochloric acid absorption amount Measured according to JIS K1469-4:2003.
(4) DBP absorption amount The value measured by the method described in Method B of JIS K6221 was converted to a value equivalent to JIS K6217-4:2008 using the above formula (a).
(5) Average primary particle diameter The diameters of 100 or more randomly selected carbon black primary particles were measured from a 50,000x image taken using a transmission electron microscope, and the average value was calculated.
(6) Ash content Measured according to JIS K1469:2003.
(7) Iron content Pretreated by acid decomposition method according to JIS K0116:2014, and measured by high frequency inductively coupled plasma mass spectrometry.
(8) Evaluation of slurry viscosity 3 parts by mass of carbon black and 97 parts by mass of N-methyl-2-pyrrolidone (manufactured by Kanto Kagaku Co., Ltd.) as a dispersion medium were added to -310") for 30 minutes at a rotational speed of 2000 rpm to prepare a carbon black slurry. The viscosity of this slurry at 25° C. was evaluated using a viscoelasticity measuring machine (“MCR102” manufactured by Anton Paar, φ30 mm, using a cone plate with an angle of 3°, gap 1 mm). Measurements were made while changing the shear rate from 0.01 s -1 to 100 s -1 , and the viscosity at a shear rate of 10 s -1 was determined. The measurement results are shown in Table 2.
(9) Sulfur content 1 g of a carbon black sample was precisely weighed into a magnetic boat and inserted into a reaction tube of a combustion absorption device heated to 1300°C. An absorption bottle containing an absorption liquid (3.5 ml of hydrogen peroxide solution was diluted with pure water to make 1 L) was connected, oxygen gas was supplied, and combustion gas was passed through the absorption bottle. The obtained absorption liquid was introduced into an ion chromatography analyzer, the peak area of sulfate ions was measured, and the sulfur content in the sample was calculated based on a calibration curve prepared in advance from a sulfate ion standard solution.
＜燃料電池用触媒の製造＞
　カーボンブラックに、白金粒子を以下の方法で担持させた。
　白金溶液として、白金濃度４．６質量％のジニトロジアンミン白金硝酸溶液を１０００ｇ（白金含有量：４６ｇ）準備し、この白金溶液に４６ｇのカーボンブラックを浸漬させ、撹拌後、還元剤として１００％エタノールを１００ｍＬ添加した。次いで、加熱還流下で７時間、撹拌混合し、白金粒子をカーボンブラックに担持させた。濾過、乾燥を行い、白金粒子の担持量が、カーボンブラック１００質量部に対して５０質量部の燃料電池用触媒を得た。得られた燃料電池用触媒について、ＴＥＭ観察（倍率１０万倍）により１０００個の白金粒子の粒径を測定し、その平均値を求めた。評価結果を表２に示す。得られた燃料電池用触媒は、１００％水素ガス中で９００℃、１時間保持することによりアニール処理を行った。 <Manufacture of fuel cell catalyst>
Platinum particles were supported on carbon black using the following method.
As a platinum solution, prepare 1000 g (platinum content: 46 g) of a dinitrodiammine platinum nitric acid solution with a platinum concentration of 4.6% by mass. 46 g of carbon black is immersed in this platinum solution, and after stirring, 100% ethanol is added as a reducing agent. 100 mL of was added. Next, the mixture was stirred and mixed under heating and reflux for 7 hours, so that the platinum particles were supported on the carbon black. Filtration and drying were performed to obtain a fuel cell catalyst having a supported amount of platinum particles of 50 parts by mass based on 100 parts by mass of carbon black. Regarding the obtained fuel cell catalyst, the particle size of 1000 platinum particles was measured by TEM observation (magnification: 100,000 times), and the average value was determined. The evaluation results are shown in Table 2. The obtained fuel cell catalyst was annealed by holding it at 900° C. for 1 hour in 100% hydrogen gas.
＜電極触媒層の製造＞
　燃料電池用触媒０．０５ｇに、５質量％のナフィオン溶液（シグマ－アルドリッチ社製、Ｎａｆｉｏｎ　１１００ＥＷ）０．１ｇと２－プロパノール０．６ｇを添加し、混合して、触媒ペーストとした。次いで、白金の含有量が０．３ｍｇ／ｃｍ２となるように触媒ペーストをカーボンペーパーに塗布し、室温で乾燥して、電極触媒層を得た。
　得られた電極触媒層の表面をＳＥＭ（倍率１０００倍）を用いて観察し、縦１００μｍ×横１００μｍの領域に存在する１０μｍ以上の凝集粒子の個数を求めた。ここで凝集粒子のサイズは各凝集粒子を取り囲むことのできる最小円の直径から求めた。結果を表３に示す。 <Manufacture of electrode catalyst layer>
To 0.05 g of a fuel cell catalyst, 0.1 g of a 5% by mass Nafion solution (Nafion 1100EW, manufactured by Sigma-Aldrich) and 0.6 g of 2-propanol were added and mixed to form a catalyst paste. Next, a catalyst paste was applied to carbon paper so that the platinum content was 0.3 mg/cm 2 and dried at room temperature to obtain an electrode catalyst layer.
The surface of the obtained electrode catalyst layer was observed using a SEM (magnification: 1000 times), and the number of aggregated particles of 10 μm or more existing in an area of 100 μm in length×100 μm in width was determined. Here, the size of the aggregated particles was determined from the diameter of the smallest circle that could surround each aggregated particle. The results are shown in Table 3.
＜燃料電池の製造＞
　上記で得られた電極触媒層をカソード電極として、燃料電池を製造した。
　まず、燃料電池用触媒を「ＴＥＣ１０Ｅ５０Ｅ」（田中貴金属工業社製）に変更したこと以外は、上記＜電極触媒層の製造＞と同様の方法で、アノード電極を作製した。ナフィオン膜、カソード電極及びアノード電極を、カソード電極及びアノード電極がナフィオン膜を挟んで対向するように重ね合わせて、１３０℃、９．８ＭＰａで３分間プレスしＭＥＡを得た。次いで、ＭＥＡの上下面にそれぞれセパレータ、ガスケット、エンドプレートをこの順で重ね、４本のネジで固定化して燃料電池を製造した。 <Manufacture of fuel cells>
A fuel cell was manufactured using the electrode catalyst layer obtained above as a cathode electrode.
First, an anode electrode was produced in the same manner as <Manufacture of electrode catalyst layer> above, except that the fuel cell catalyst was changed to "TEC10E50E" (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.). The Nafion membrane, the cathode electrode, and the anode electrode were overlapped so that the cathode electrode and the anode electrode faced each other with the Nafion membrane in between, and pressed at 130° C. and 9.8 MPa for 3 minutes to obtain an MEA. Next, a separator, a gasket, and an end plate were stacked on the upper and lower surfaces of the MEA in this order, and fixed with four screws to produce a fuel cell.
　得られた燃料電池について、７０℃の条件で、アノード電極に相対湿度１００％の水素ガスを１Ｌ／ｍｉｎで供給し、カソード電極に相対湿度１００％の酸素ガスを１Ｌ／ｍｉｎで供給し、５００ｍＡ／ｃｍ２の定電流駆動で作動させ、初期の出力電圧を測定した。次に、電流値を０ｍＡ／ｃｍ２と５００ｍＡ／ｃｍ２の間で３００００サイクル繰り返し変動させた。その後、５００ｍＡ／ｃｍ２の定電流駆動で、耐久試験後の出力電圧を測定した。評価結果を表３に示す。 Regarding the obtained fuel cell, hydrogen gas with a relative humidity of 100% was supplied to the anode electrode at a rate of 1 L/min at 70° C., oxygen gas with a relative humidity of 100% was supplied to the cathode electrode at a rate of 1 L/min, and the temperature was 500 mA. It was operated with a constant current drive of /cm 2 and the initial output voltage was measured. Next, the current value was repeatedly varied between 0 mA/cm 2 and 500 mA/cm 2 for 30,000 cycles. Thereafter, the output voltage after the durability test was measured by driving at a constant current of 500 mA/cm 2 . The evaluation results are shown in Table 3.
（実施例２及び３）
　＜カーボンブラックの製造＞における酸素の供給量を、２２Ｎｍ３／ｈ（実施例２）又は２４Ｎｍ３／ｈ（実施例３）に変更したこと以外は、実施例１と同様にしてカーボンブラックの製造し、評価した。結果を表１及び表２に示す。また、得られたカーボンブラックを用いて、実施例１と同様にして、燃料電池用触媒の製造、電極触媒層の製造及び燃料電池の製造を行い、評価した。結果を表３に示す。 (Example 2 and 3)
Carbon black was produced in the same manner as in Example 1, except that the amount of oxygen supplied in <Production of carbon black> was changed to 22 Nm 3 /h (Example 2) or 24 Nm 3 /h (Example 3). and evaluated. The results are shown in Tables 1 and 2. Further, using the obtained carbon black, a fuel cell catalyst, an electrode catalyst layer, and a fuel cell were produced and evaluated in the same manner as in Example 1. The results are shown in Table 3.
（実施例４）
　＜カーボンブラックの製造＞において、トルエンの供給時の温度を１００℃に変更したこと以外は、実施例１と同様にしてカーボンブラックを作製し、評価した。結果を表１及び表２に示す。また、得られたカーボンブラックを用いて、実施例１と同様にして、燃料電池用触媒の製造、電極触媒層の製造及び燃料電池の製造を行い、評価した。結果を表３に示す。 (Example 4)
In <Production of carbon black>, carbon black was produced and evaluated in the same manner as in Example 1, except that the temperature during supply of toluene was changed to 100°C. The results are shown in Tables 1 and 2. Further, using the obtained carbon black, a fuel cell catalyst, an electrode catalyst layer, and a fuel cell were produced and evaluated in the same manner as in Example 1. The results are shown in Table 3.
（実施例５）
　＜カーボンブラックの製造＞において、アセチレンの供給時の温度を８５℃、トルエンの供給時の温度を１００℃にそれぞれ変更したこと以外は、実施例１と同様にしてカーボンブラックを作製し、評価した。結果を表１及び表２に示す。また、得られたカーボンブラックを用いて、実施例１と同様にして、燃料電池用触媒の製造、電極触媒層の製造及び燃料電池の製造を行い、評価した。結果を表３に示す。 (Example 5)
In <Manufacture of carbon black>, carbon black was produced and evaluated in the same manner as in Example 1, except that the temperature during acetylene supply was changed to 85 ° C., and the temperature during toluene supply was changed to 100 ° C. . The results are shown in Tables 1 and 2. Further, using the obtained carbon black, a fuel cell catalyst, an electrode catalyst layer, and a fuel cell were produced and evaluated in the same manner as in Example 1. The results are shown in Table 3.
（実施例６）
　＜カーボンブラックの製造＞において、アセチレンの供給時の温度を８５℃、トルエンの供給時の温度を８５℃にそれぞれ変更したこと以外は、実施例１と同様にしてカーボンブラックを作製し、評価した。結果を表１及び表２に示す。また、得られたカーボンブラックを用いて、実施例１と同様にして、燃料電池用触媒の製造、電極触媒層の製造及び燃料電池の製造を行い、評価した。結果を表３に示す。 (Example 6)
In <Production of carbon black>, carbon black was produced and evaluated in the same manner as in Example 1, except that the temperature during acetylene supply was changed to 85 ° C., and the temperature during toluene supply was changed to 85 ° C. . The results are shown in Tables 1 and 2. Further, using the obtained carbon black, a fuel cell catalyst, an electrode catalyst layer, and a fuel cell were produced and evaluated in the same manner as in Example 1. The results are shown in Table 3.
（実施例７）
　アセチレンの供給量を１３Ｎｍ３／ｈ、トルエンの供給量を３５ｋｇ／ｈ、酸素の供給量を２６Ｎｍ３／ｈにそれぞれ変更したこと以外は、実施例１と同様にしてカーボンブラックを作製し、評価した。結果を表１及び表２に示す。また、得られたカーボンブラックを用いて、実施例１と同様にして、燃料電池用触媒の製造、電極触媒層の製造及び燃料電池の製造を行い、評価した。結果を表３に示す。 (Example 7)
Carbon black was produced and evaluated in the same manner as in Example 1, except that the acetylene supply rate was changed to 13 Nm 3 /h, the toluene supply rate was changed to 35 kg/h, and the oxygen supply rate was changed to 26 Nm 3 /h. did. The results are shown in Tables 1 and 2. Further, using the obtained carbon black, a fuel cell catalyst, an electrode catalyst layer, and a fuel cell were produced and evaluated in the same manner as in Example 1. The results are shown in Table 3.
（実施例８）
　トルエンに代えて３２ｋｇ／ｈのベンゼンを１１５℃に加熱して供給したこと以外は、実施例１と同様にしてカーボンブラックを作製し、評価した。結果を表１及び表２に示す。また、得られたカーボンブラックを用いて、実施例１と同様にして、燃料電池用触媒の製造、電極触媒層の製造及び燃料電池の製造を行い、評価した。結果を表３に示す。 (Example 8)
Carbon black was produced and evaluated in the same manner as in Example 1, except that 32 kg/h of benzene was heated to 115° C. and supplied instead of toluene. The results are shown in Tables 1 and 2. Further, using the obtained carbon black, a fuel cell catalyst, an electrode catalyst layer, and a fuel cell were produced and evaluated in the same manner as in Example 1. The results are shown in Table 3.
（比較例１）
　酸素の供給量を２０Ｎｍ３／ｈに変更したこと以外は、実施例１と同様にしてカーボンブラックを作製し、評価した。結果を表１及び表２に示す。また、得られたカーボンブラックを用いて、実施例１と同様にして、燃料電池用触媒の製造、電極触媒層の製造及び燃料電池の製造を行い、評価した。結果を表３に示す。 (Comparative example 1)
Carbon black was produced and evaluated in the same manner as in Example 1, except that the amount of oxygen supplied was changed to 20 Nm 3 /h. The results are shown in Tables 1 and 2. Further, using the obtained carbon black, a fuel cell catalyst, an electrode catalyst layer, and a fuel cell were produced and evaluated in the same manner as in Example 1. The results are shown in Table 3.
（比較例２）
　アセチレンの供給量を１１Ｎｍ３／ｈ、トルエンの供給量を３０ｋｇ／ｈ、酸素の供給量を２４Ｎｍ３／ｈに変更したこと以外は、実施例１と同様にしてカーボンブラックを作製し、評価した。結果を表１及び表２に示す。また、得られたカーボンブラックを用いて、実施例１と同様にして、燃料電池用触媒の製造、電極触媒層の製造及び燃料電池の製造を行い、評価した。結果を表３に示す。 (Comparative example 2)
Carbon black was prepared and evaluated in the same manner as in Example 1, except that the acetylene supply rate was changed to 11 Nm 3 /h, the toluene supply rate was changed to 30 kg/h, and the oxygen supply rate was changed to 24 Nm 3 /h. . The results are shown in Tables 1 and 2. Further, using the obtained carbon black, a fuel cell catalyst, an electrode catalyst layer, and a fuel cell were produced and evaluated in the same manner as in Example 1. The results are shown in Table 3.
（実施例９）
　比較例１で得られたカーボンブラックを７２０℃に加熱された電気炉内にて酸化処理して、カーボンブラックを得た。得られたカーボンブラックを実施例１と同様に評価した。結果を表１及び表２に示す。また、得られたカーボンブラックを用いて、実施例１と同様にして、燃料電池用触媒の製造、電極触媒層の製造及び燃料電池の製造を行い、評価した。結果を表３に示す。 (Example 9)
The carbon black obtained in Comparative Example 1 was oxidized in an electric furnace heated to 720° C. to obtain carbon black. The obtained carbon black was evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2. Further, using the obtained carbon black, a fuel cell catalyst, an electrode catalyst layer, and a fuel cell were produced and evaluated in the same manner as in Example 1. The results are shown in Table 3.
（実施例１０）
　乾式サイクロン装置の分級条件を変更して灰分の含有量を調整したこと以外は、実施例１と同様にしてカーボンブラックを作製し、評価した。結果を表１及び表２に示す。また、得られたカーボンブラックを用いて、実施例１と同様にして、燃料電池用触媒の製造、電極触媒層の製造及び燃料電池の製造を行い、評価した。結果を表３に示す。 (Example 10)
Carbon black was produced and evaluated in the same manner as in Example 1, except that the classification conditions of the dry cyclone device were changed to adjust the ash content. The results are shown in Tables 1 and 2. Further, using the obtained carbon black, a fuel cell catalyst, an electrode catalyst layer, and a fuel cell were produced and evaluated in the same manner as in Example 1. The results are shown in Table 3.
（実施例１１）
　鉄除去用磁石の磁束密度条件を変更して鉄の含有量を調整したこと以外は、実施例１と同様にしてカーボンブラックを作製し、評価した。結果を表１及び表２に示す。また、得られたカーボンブラックを用いて、実施例１と同様にして、燃料電池用触媒の製造、電極触媒層の製造及び燃料電池の製造を行い、評価した。結果を表３に示す。 (Example 11)
Carbon black was produced and evaluated in the same manner as in Example 1, except that the iron content was adjusted by changing the magnetic flux density conditions of the iron removal magnet. The results are shown in Tables 1 and 2. Further, using the obtained carbon black, a fuel cell catalyst, an electrode catalyst layer, and a fuel cell were produced and evaluated in the same manner as in Example 1. The results are shown in Table 3.
（比較例３）
　アセチレンの供給量を３８Ｎｍ３／ｈに変更し、トルエンを供給せず、酸素の供給量を１０Ｎｍ３／ｈに変更したこと以外は、実施例１と同様にしてカーボンブラックを作製し、評価した。結果を表１及び表２に示す。また、得られたカーボンブラックを用いて、実施例１と同様にして、燃料電池用触媒の製造、電極触媒層の製造及び燃料電池の製造を行い、評価した。結果を表３に示す。 (Comparative example 3)
Carbon black was produced and evaluated in the same manner as in Example 1, except that the acetylene supply rate was changed to 38Nm 3 /h, toluene was not supplied, and the oxygen supply rate was changed to 10Nm 3 /h. . The results are shown in Tables 1 and 2. Further, using the obtained carbon black, a fuel cell catalyst, an electrode catalyst layer, and a fuel cell were produced and evaluated in the same manner as in Example 1. The results are shown in Table 3.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　上記とおり、実施例のカーボンブラックを燃料電池用触媒用担体として用いることで、電極触媒層における凝集が抑制され、高性能の燃料電池が得られており、この結果から、実施例の燃料電池用触媒は、高い分散性と高い反応効率とを両立可能であることが確認された。 As mentioned above, by using the carbon black of the example as a carrier for the fuel cell catalyst, agglomeration in the electrode catalyst layer was suppressed and a high-performance fuel cell was obtained. It was confirmed that the catalyst is capable of achieving both high dispersibility and high reaction efficiency.
　本発明の燃料電池用触媒用担体は、高い分散性と高い反応効率とを両立可能な燃料電池用触媒の実現のために好適に利用できる。また、本発明の燃料電池用触媒は、高い分散性と高い反応効率とを両立でき、燃料電池用触媒として好適に利用できる。 The fuel cell catalyst carrier of the present invention can be suitably used to realize a fuel cell catalyst that can achieve both high dispersibility and high reaction efficiency. Further, the fuel cell catalyst of the present invention can achieve both high dispersibility and high reaction efficiency, and can be suitably used as a fuel cell catalyst.

Claims (8)

  1. 　カーボンブラックからなる燃料電池用触媒用担体であって、
    　比表面積が１７０ｍ２／ｇ以上４００ｍ２／ｇ以下であり、
    　昇温脱離ガス分析法により検出される、ｍ／ｚ５７のピークのピーク面積（Ｓ１）に対するｍ／ｚ１２８のピークのピーク面積（Ｓ２）の比（Ｓ２／Ｓ１）が２．００未満である、
    　燃料電池用触媒用担体。     A fuel cell catalyst carrier made of carbon black,
    The specific surface area is 170 m 2 /g or more and 400 m 2 /g or less,
    The ratio (S 2 /S 1 ) of the peak area (S 1 ) of the m/z 57 peak to the peak area (S 2 ) of the m/z 128 peak detected by temperature programmed desorption gas analysis is 2.00. is less than
    Support for catalysts for fuel cells.
  2. 　Ｎ－メチル－２－ピロリドンを分散媒とした３質量％のスラリーとしたとき、２５℃、せん断速度１０ｓ－１におけるスラリー粘度が、４００ｍＰａ・ｓ以上１５００ｍＰａ・ｓ以下となる、請求項１に記載の燃料電池用触媒用担体。 According to claim 1, when a 3% by mass slurry is prepared using N-methyl-2-pyrrolidone as a dispersion medium, the slurry viscosity at 25°C and a shear rate of 10 s -1 is 400 mPa·s or more and 1500 mPa·s or less. catalyst carrier for fuel cells.
  3. 　塩酸吸液量が３９ｍＬ／５ｇ以上である、請求項１に記載の燃料電池用触媒用担体。 The fuel cell catalyst carrier according to claim 1, which has a hydrochloric acid absorption amount of 39 mL/5 g or more.
  4. 　ＤＢＰ吸収量が２００ｍＬ／１００ｇ以上４００ｍＬ／１００ｇ以下である、請求項１に記載の燃料電池用触媒用担体。 The fuel cell catalyst carrier according to claim 1, wherein the DBP absorption amount is 200 mL/100 g or more and 400 mL/100 g or less.
  5. 　請求項１～４のいずれか一項に記載の燃料電池用触媒用担体に、白金粒子及び白金合金粒子からなる群より選択される少なくとも一種の金属粒子を担持させてなる、燃料電池用触媒。 A fuel cell catalyst comprising at least one metal particle selected from the group consisting of platinum particles and platinum alloy particles supported on the fuel cell catalyst carrier according to any one of claims 1 to 4.
  6. 　請求項５に記載の燃料電池用触媒と電解質とを含有する、電極触媒層。 An electrode catalyst layer containing the fuel cell catalyst according to claim 5 and an electrolyte.
  7. 　請求項６に記載の電極触媒層を備える、燃料電池。 A fuel cell comprising the electrode catalyst layer according to claim 6.
  8. 　第一のセパレータと、第一のガス拡散層と、アノード電極触媒層と、電解質膜と、カソード電極触媒層と、第二のガス拡散層と、第二のセパレータと、を備え、
    　前記アノード電極触媒層及び前記カソード電極触媒層のうち、少なくとも一方が請求項６に記載の電極触媒層である、燃料電池。     comprising a first separator, a first gas diffusion layer, an anode electrode catalyst layer, an electrolyte membrane, a cathode electrode catalyst layer, a second gas diffusion layer, and a second separator,
    A fuel cell, wherein at least one of the anode electrode catalyst layer and the cathode electrode catalyst layer is the electrode catalyst layer according to claim 6.
PCT/JP2023/012971 2022-05-13 2023-03-29 Catalyst carrier for fuel cells, catalyst for fuel cells, electrode catalyst layer, and fuel cell WO2023218790A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006252938A (en) * 2005-03-10 2006-09-21 Gs Yuasa Corporation:Kk Electrode for solid polymer electrolyte fuel cell and its manufacturing method
WO2015045083A1 (en) * 2013-09-27 2015-04-02 株式会社日立製作所 Fuel cell electrode catalyst and membrane electrode assembly using same
WO2019017252A1 (en) * 2017-07-18 2019-01-24 住友電気工業株式会社 Porous metal body and current collector for nickel metal-hydride battery

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006252938A (en) * 2005-03-10 2006-09-21 Gs Yuasa Corporation:Kk Electrode for solid polymer electrolyte fuel cell and its manufacturing method
WO2015045083A1 (en) * 2013-09-27 2015-04-02 株式会社日立製作所 Fuel cell electrode catalyst and membrane electrode assembly using same
WO2019017252A1 (en) * 2017-07-18 2019-01-24 住友電気工業株式会社 Porous metal body and current collector for nickel metal-hydride battery

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