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EP-4737522-A1 - OXYGEN-TREATED CARBON BLACK, ACTIVATED CARBON BLACK, CARBON MATERIAL FOR CATALYST CARRIERS OF POLYMER ELECTROLYTE FUEL CELLS, CATALYST LAYER FOR POLYMER ELECTROLYTE FUEL CELLS, AND FUEL CELL

EP4737522A1EP 4737522 A1EP4737522 A1EP 4737522A1EP-4737522-A1

Abstract

A carbon material for a catalyst carrier of a solid polymer fuel cell, the carbon material including porous activated carbon black satisfying the following requirements: (F) a BET specific surface area (m 2 /g) is from 400 to 1200, (G) Σ 2-6 is from 0.20 to less than 0.70 in a case in which an integrated value of a volume of a pore having a pore size of from 2 to less than to 6 nm is Σ 2-6 in a mesopore distribution, (H) Σ 6-10 /Σ 2-6 is 0.120 to 0.500 in a case in which an integrated value of a volume of a pore having a pore size of from 2 to less than to 6 nm is Σ 2-6 and an integrated value of a volume of a pore having a pore size of from 6 to less than to 10 nm is Σ 6-10 in a mesopore distribution, and (I) I D /I G is from 1.20 to 2.20 in a case in which an intensity in a D band is I D and an intensity in a G band is I G in a Raman spectrum.

Inventors

  • IIJIMA, TAKASHI
  • NEGI, NORIYUKI
  • SHIMIZU, TAKAYUKI
  • TADOKORO, KENICHIRO
  • MASAKI, KAZUYOSHI

Assignees

  • Nippon Steel Chemical & Material Co., Ltd.

Dates

Publication Date
20260506
Application Date
20240628

Claims (7)

  1. Oxygen-treated carbon black satisfying the following requirement (A): (A) a content of oxygen (% by mass) is from S BET /100 to 8.00 in a case in which a BET specific surface area calculated by nitrogen gas adsorption is S BET (m 2 /g).
  2. The oxygen-treated carbon black according to claim 1, further satisfying the following requirement (B): (B) S BET (m 2 /g) is from 5500/D to 500 in a case in which the BET specific surface area calculated by nitrogen gas adsorption is S BET (m 2 /g) and a primary particle size of the oxygen-treated carbon black is D (nm).
  3. Activated carbon black simultaneously satisfying the following requirements (C), (D), and (E): (C) a BET specific surface area (m 2 /g) calculated by nitrogen gas adsorption isotherm measurement is from 700 to 1500, (D) Σ 2-6 is from 0.22 to less than 1.00 in a case in which an integrated value of a pore volume of a pore having a pore size of from 2 nm to less than 6 nm, in a mesopore distribution determined by analysis of a nitrogen gas adsorption isotherm with a BJH (Barrett Joyner Halenda) method, is Σ 2-6 , and (E) Σ 6-10 /Σ 2-6 is from 0.100 to 0.490 in a case in which an integrated value of a pore volume of a pore having a pore size of from 2 nm to less than 6 nm is Σ 2-6 and an integrated value of a pore volume of a pore having a pore size of from 6 nm to less than 10 nm is Σ 6-10 , in a mesopore distribution determined by analysis of a nitrogen gas adsorption isotherm with a BJH (Barrett Joyner Halenda) method.
  4. A carbon material for a catalyst carrier of a solid polymer fuel cell, the carbon material comprising porous activated carbon black simultaneously satisfying the following requirements (F), (G), (H), and (I): (F) a BET specific surface area (m 2 /g) by nitrogen gas adsorption measurement is from 400 to 1200, (G) Σ 2-6 is from 0.20 to less than 0.70 in a case in which an integrated value of a pore volume of a pore having a pore size of from 2 nm to less than 6 nm, in a mesopore distribution determined by analysis of a nitrogen gas adsorption isotherm with a BJH (Barrett Joyner Halenda) method, is Σ 2-6 , (H) Σ 6-10 /Σ 2-6 is from 0.120 to 0.500 in a case in which an integrated value of a pore volume of a pore having a pore size of from 2 nm to less than 6 nm is Σ 2-6 and an integrated value of a pore volume of a pore having a pore size of from 6 nm to less than 10 nm is Σ 6-10 , in a mesopore distribution determined by analysis of a nitrogen gas adsorption isotherm with a BJH (Barrett Joyner Halenda) method, and (I) I D /I G is from 1.20 to 2.20 in a case in which an intensity in a D band of from 1300 to 1360 cm -1 is designated as I D and an intensity in a G band of from 1560 to 1620 cm -1 is designated as I G in a Raman spectrum obtained by Raman spectrometry.
  5. A catalyst layer for a solid polymer fuel cell, the catalyst layer comprising the carbon material for a catalyst carrier of a solid polymer fuel cell according to claim 4.
  6. A fuel cell comprising the catalyst layer for a solid polymer fuel cell according to claim 5.
  7. The fuel cell according to claim 6, wherein the catalyst layer for a solid polymer fuel cell is a catalyst layer on a cathode side.

Description

Technical Field The present disclosure relates to a carbon material for a catalyst carrier of a solid polymer fuel cell, a catalyst layer for a solid polymer fuel cell, and a fuel cell. Background Art A solid polymer fuel cell which is one of fuel batteries includes paired catalyst layers placed on both surfaces of a solid polymer electrolyte membrane, a gas diffusion layer placed outside each of the catalyst layers, and a separator placed outside such each. One catalyst layer of the paired catalyst layers serves as an anode of the solid polymer fuel cell and the other catalyst layer serves as a cathode of the solid polymer fuel cell. In a usual solid polymer fuel cell, plural unit cells each having the above constituent components are stacked in order to obtain the desired output. A fuel gas such as hydrogen is introduced into the separator on the anode side. The gas diffusion layer on the anode side allows fuel to be diffused and then introduced into the anode. The anode includes a catalyst component, a catalyst carrier carrying a catalyst for a fuel cell, and an electrolyte material having proton conductivity. Hereinafter, a catalyst component promoting an electricity generation reaction (oxidation reaction or reduction reaction described later) in a fuel cell is also referred to as "catalyst for a fuel cell". The catalyst carrier is often constituted from a porous carbon material. The oxidation reaction of the fuel gas occurs to generate protons and electrons on the catalyst for a fuel cell. For example, in a case in which the fuel gas is a hydrogen gas, the following oxidation reaction occurs. H2→2H++2e−E0=0V The protons generated in the oxidation reaction are introduced into the cathode through the electrolyte material (ionomer) in the anode and the solid polymer electrolyte membrane. The electrons are introduced into an external circuit through the catalyst carrier, the gas diffusion layer, and the separator. The electrons are worked in the external circuit, and then introduced into the separator on the cathode side. The electrons are then introduced into the cathode through the separator on the cathode side and the gas diffusion layer on the cathode side. The solid polymer electrolyte membrane is constituted from an electrolyte material having proton conductivity. The solid polymer electrolyte membrane introduces the protons generated in the oxidation reaction, into the cathode. An oxidizing gas such as an oxygen gas or air is introduced into the separator on the cathode side. The gas diffusion layer on the cathode side allows the oxidizing gas to be diffused and then introduced into the cathode. The cathode includes a catalyst for a fuel cell, a catalyst carrier carrying the catalyst for a fuel cell, and an electrolyte material having proton conductivity. The catalyst carrier is often constituted from a porous carbon material. The reduction reaction of the oxidizing gas occurs to generate water on the catalyst for a fuel cell. For example, in a case in which the oxidizing gas is an oxygen gas or air, the following reduction reaction occurs. O2+4H++4e−→2H2OE0=1.23V The water generated in the reduction reaction is discharged together with the unreacted oxidizing gas, outside the fuel cell. Thus, the solid polymer fuel cell generates electricity by use of the difference in free energy (difference in potential) generated along with the oxidation reaction of the fuel gas. In other words, the free energy generated in the oxidation reaction is converted to the working to be performed in the external circuit with the electrons. Meanwhile, porous carbon materials (hereinafter, also referred to as "carbon carriers") applicable to catalyst carriers of solid polymer fuel batteries have been studied and variously proposed. For example, Patent Literature 1 proposes "A carbon material for a catalyst carrier, in which the carbon material is used in a catalyst carrier of a solid polymer fuel cell and has a three-dimensional dendritic structure three-dimensionally branched, and the following (1) and (2) are simultaneously satisfied.". (1) The DL/DH is 1.5 or more in a case in which the cumulative distribution [%] of a particle having a size of 1 µm or less is defined as DL and the cumulative distribution [%] of a particle having a size of more than 1 µm is defined as DH on the volume size basis in particle size distribution measurement with a laser diffraction/scattering type particle size distribution meter.(2) The mode diameter in a pore size range of from 20 nm to 200 nm, as measured by a mercury porosimetry method, is from 40 nm to 70 nm. Patent Literature 2 proposes "A carbon material for a catalyst carrier of a solid polymer fuel cell, in which the carbon material is a porous carbon material, and the following (1), (2), (3) and (4) are simultaneously satisfied.". (1) The intensity ratio (I750/Ipeak) between the intensity (I750) at 750°C and the peak intensity (Ipeak) near 690°C in a derivative thermogravimetri