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EP-4738481-A1 - CARBON MATERIAL FOR CATALYST CARRIER OF SOLID POLYMER FUEL CELL, CATALYST LAYER FOR SOLID POLYMER FUEL CELL, AND FUEL CELL

EP4738481A1EP 4738481 A1EP4738481 A1EP 4738481A1EP-4738481-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 (A), (B), (C), and (D): (A) an average primary particle size is from more than 30 nm to 100 nm, (B) a BET specific surface area is from 350 m 2 /g to 800 m 2 /g, (C) Lc (002) obtained by analyzing a peak at a diffraction angle 2θ of from 20° to 26.5° in an XRD spectrum obtained with XRD (X-ray diffraction) measurement is from 1.7 nm to 4.0 nm, and (D) La (110) obtained by analyzing a peak at a diffraction angle 2θ of from 70° to 80° in the XRD spectrum obtained with XRD (X-ray diffraction) measurement is 3.5 nm or less.

Inventors

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

Assignees

  • NIPPON STEEL CHEMICAL & MATERIAL CO., LTD.

Dates

Publication Date
20260506
Application Date
20240628

Claims (6)

  1. A carbon material for a catalyst carrier of a solid polymer fuel cell, the carbon material comprising porous activated carbon black satisfying the following requirements (A), (B), (C), and (D): (A) an average primary particle size is from more than 30 nm to 100 nm, (B) a BET specific surface area is from 350 m 2 /g to 800 m 2 /g, (C) Lc (002) obtained by analyzing a peak at a diffraction angle 2θ of from 20° to 26.5° in an XRD spectrum obtained with XRD (X-ray diffraction) measurement is from 1.7 nm to 4.0 nm, and (D) La (110) obtained by analyzing a peak at a diffraction angle 2θ of from 70° to 80° in the XRD spectrum obtained with XRD (X-ray diffraction) measurement is 3.5 nm or less.
  2. The carbon material for a catalyst carrier of a solid polymer fuel cell according to claim 1, wherein the following requirement (E) is further satisfied: (E) a ratio (Lc (002)/La (110)) between the Lc (002) and the La (110) is from 0.6 to 1.2.
  3. The carbon material for a catalyst carrier of a solid polymer fuel cell according to claim 1, wherein the average primary particle size is from 40 nm to 100 nm.
  4. 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 any one of claim 1 to claim 3.
  5. A fuel cell comprising the catalyst layer for a solid polymer fuel cell according to claim 4.
  6. The fuel cell according to claim 5, 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 reducing gas such as hydrogen is introduced into the separator on the anode side. The gas diffusion layer on the anode side allows the reducing gas 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 (ionomer or the like) having proton conductivity. The catalyst carrier is often constituted from a carbon material. The oxidation reaction of the reducing gas occurs to generate protons and electrons on the catalyst component. For example, in a case in which the reducing gas is a hydrogen gas, the following oxidation reaction occurs.         H2 → 2H+ + 2e- (E0 = 0 V) The protons generated in the oxidation reaction are introduced into the cathode through the electrolyte material 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 (generate electricity) in an 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 component, a catalyst carrier carrying the catalyst component, and an electrolyte material (ionomer) having proton conductivity. The catalyst carrier is often constituted from a carbon material. The reduction reaction of the oxidizing gas occurs to generate water on the catalyst component. For example, in a case in which the oxidizing gas is an oxygen gas or air, the following reduction reaction occurs.         O2+4H++4e-→2H2O (E0 = 1.23 V) 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 energy (difference in potential) between the oxidation reaction and the reduction reaction. In other words, the electrons generated in the oxidation reaction work in the external circuit. Meanwhile, use of porous carbon black in catalyst carriers has been conventionally proposed from the viewpoint of electricity generation performance of fuel batteries. Non-Patent Literature 1 reports that a catalytic metal carried in a pore formed inside of porous carbon black does not receive reaction inhibition (poisoning) due to covering with an ionomer co-existing in a catalyst layer and thus is highly active. Patent Literature 1 proposes porous carbon black having an average particle size of from 20 to 100 nm, in which the volume of a hole having a hole diameter of from 4 to 20 nm in the porous carbon black is from 0.23 to 0.78 cm3/g. Patent Literature 2 proposes a method including contacting a carbon black starting material and an oxidant in a fluidized bed, as a method including making carbon black porous to increase the surface area. Conventionally, high crystallization of porous carbon black by firing has been proposed from the viewpoint of duration performance of fuel batteries. Patent Literature 3 proposes high-crystalline carbon black having a BET specific surface area of from 300 to 700 m2/g and a crystallite size Lc of 2.0 nm or more in order to impart durability. Patent Literature 4 proposes porous carbon in which the Lc (002) is 2.0 nm or more, the ratio D/G of the peak area of a D1-band (1350 cm-1) with respect to the peak area of a G-band (1590 cm-1) in a spectrum of a carbon surface by a Raman spectrometric method is from 0.5 to 2.5, the porous carbon has a pore including a mesopore, and the mesopore volume is from 0.35 to 1.3 cm3/g. In particular, porous carbon blac