Fuel Cell Anode Catalyst Pore Structure for Hydrogen Diffusion

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Solution Overview

Problem

Conventional electrode catalysts for fuel cells, especially when applied to the anode, face issues of increased hydrogen diffusion resistance and overvoltage due to catalyst particles with small average sizes and high specific surface areas, leading to reduced fuel cell performance.

Innovation Solution

An anode electrode catalyst with a carbon support having pore sizes of 10 nm or less and a pore volume of 1.1 to 8.4 cm^3/g, supporting catalyst particles with sizes of 3.1 nm or less, at a density of 15% to 40% by mass, which reduces hydrogen diffusion resistance and anode overvoltage, thereby preventing performance degradation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If catalyst particles with small average size are used to increase specific surface area, then catalyst density increases, but hydrogen diffusion resistance increases and overvoltage occurs

Engineering Contradiction:
Improvecatalyst particle densityVSAvoidhydrogen diffusion resistance
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating a non-uniform pore size distribution within the carbon support. Small pores (1-10 nm) provide high surface area for catalyst support, while larger pores (10-100 nm) create diffusion pathways. This spatial variation in pore quality allows different regions to serve different functions: catalyst anchoring in small pores and mass transport in larger pores, thereby resolving the contradiction between catalyst density and hydrogen diffusion.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent transitions from considering only pore size to considering pore size distribution across multiple dimensions. By introducing a hierarchical pore structure with at least two distinct pore size ranges, the invention adds a dimensional aspect to the pore structure design. This multi-dimensional approach allows simultaneous optimization of surface area (small pores) and diffusion pathways (larger pores), resolving the contradiction between catalyst density and hydrogen diffusion resistance.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Area of moving object

If catalyst particles with small average size are used, then specific surface area of catalyst increases, but fuel cell performance decreases due to overvoltage

Engineering Contradiction:
Improvecatalyst specific surface areaVSAvoidfuel cell performance
Core Design Contradiction:
Area of moving objectVSReliability

Solution Approach 1:

The patent applies local quality by creating a non-uniform pore size distribution within the carbon support. Small pores (1-10 nm) provide high surface area for catalyst support, while larger pores (10-100 nm) create diffusion pathways. This spatial variation in pore quality allows different regions to serve different functions: catalyst anchoring in small pores and mass transport in larger pores, thereby resolving the contradiction between catalyst density and hydrogen diffusion.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent transitions from considering only pore size to considering pore size distribution across multiple dimensions. By introducing a hierarchical pore structure with at least two distinct pore size ranges, the invention adds a dimensional aspect to the pore structure design. This multi-dimensional approach allows simultaneous optimization of surface area (small pores) and diffusion pathways (larger pores), resolving the contradiction between catalyst density and hydrogen diffusion resistance.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The described electrode catalyst configuration effectively inhibits overvoltage and maintains fuel cell performance by optimizing catalyst particle distribution and support structure, ensuring stable operation.

Implementation Method 1

a carbon support having at least one pore having a pore size of 10 nm or less and a pore volume of 1.1 to 8.4 cm³/g

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

a carbon support having at least one pore having a pore size of 10 nm or less and a pore volume of 1.1 to 8.4 cm³/g

Methodology Applied
Scientific EffectPorosity: Porosity

Implementation Method 3

particles of a catalyst metal having catalyst activity, such as platinum or a platinum alloy supported by the conductive support

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 4

the oxidation reaction expressed by formula (1) below proceeds on the anode side

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 5

Fuel cells generate electricity through an electrochemical reaction between hydrogen and oxygen

Methodology Applied
Scientific EffectFuel Cell: Fuel Cell

Implementation Method 6

it might cause an increase in H2 diffusion resistance

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP3185342A1Electrode catalyst for fuel cells
Publication Date: 2017.06.28 TOYOTA JIDOSHA KK
  • EP3185342A1 patent drawingFigure 1
  • EP3185342A1 patent drawingFigure 2
  • EP3185342A1 patent drawingFigure 3

AI summary

A means of inhibiting the occurrence of overvoltage in an electrode catalyst for fuel cells so as to substantially prevent reduction of fuel cell performance includes an anode electrode catalyst for fuel cells, which contains a carbon support having at least one pore having a pore size of 10 nm or less and a pore volume of 1.1 to 8.4 cm3/g and catalyst particles having particle sizes of 3.1 nm or less and supported by the carbon support so that the density of supported catalyst particles is 15% to 40% by mass.