L12 Ordered Pt-Alloy Catalyst Particle for Fuel Cell Durability

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Solution Overview

Problem

Platinum-metal alloy catalysts used in fuel cells suffer from inferior activity and durability due to elution of non-platinum metals under acidic conditions, leading to reduced performance.

Innovation Solution

A catalyst particle with an L12 structure, formed of platinum and non-platinum metal atoms, having an extent of ordering between 30 to 100% and a CO stripping LP ratio of 10% or more, which suppresses the elution of non-platinum metals and exposes high-activity crystal faces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If platinum-metal alloy catalyst is used to reduce platinum content, then cost is reduced, but activity and durability deteriorate due to elution of non-platinum metals

Engineering Contradiction:

Improveplatinum contentVSAvoiddurability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent changes the crystal structure parameter of the catalyst particle from conventional structures to specifically the L12 structure with 30-100% ordering extent. This structural parameter change suppresses the elution of non-platinum metals while maintaining catalytic activity, thereby improving durability without requiring high platinum content

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite catalyst particle consisting of platinum and non-platinum metal atoms arranged in an L12 intermetallic compound structure. This composite structure with specific ordering (30-100%) provides both cost advantage through reduced platinum content and improved durability through suppressed metal elution

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If conventional catalyst structure is used, then manufacturing is simple, but activity is insufficient for high power density

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidpower density

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent optimizes the crystal structure parameter by forming the L12 structure with 30-100% ordering extent, which exposes high-activity crystal faces. This parameter change significantly enhances catalytic activity and power density while maintaining feasibility in existing fuel cell manufacturing processes

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If non-platinum metal content is increased to reduce cost, then platinum content is reduced, but elution increases leading to inferior durability

Engineering Contradiction:

Improvenon-platinum metal contentVSAvoiddurability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent changes the structural ordering parameter to L12 structure with 30-100% ordering extent, which fundamentally alters the behavior of non-platinum metals in the alloy. This structural parameter suppresses elution of non-platinum metals even when their content is increased, enabling both cost reduction and durability improvement

Inventive Principle:

Principle #35Parameter changes

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 catalyst particle exhibits improved activity and durability, maintaining high performance even after durability tests, with a reduced platinum content, and is used to create effective electrode catalysts and fuel cells with enhanced power generation capabilities.

Implementation Method 1

the alloy particle has an L12 structure as an internal structure and has an extent of ordering of L12 structure in the range of 30 to 100%

Methodology Applied

Scientific EffectL12 structure ordering:

Implementation Method 2

exposes high-activity crystal faces

Methodology Applied

Scientific EffectCrystal face exposure:

Implementation Method 3

hydrogen contained in a fuel gas supplied to the anode (negative electrode) side is oxidized by a catalyst component, to form a proton and an electron

Methodology Applied

Scientific EffectOxidation reaction: Oxidation

Implementation Method 4

the proton and the electron, which have reached the cathode-side electrode catalyst layer, react with oxygen contained in an oxidant gas supplied to the cathode side, to produce water

Methodology Applied

Scientific EffectReduction reaction: Reduction

Data Source

PatentUS10847811B2Catalyst particle, and electrode catalyst, electrolyte membrane-electrode assembly, and fuel cell using the same

Publication Date: 2020.11.24 NISSAN MOTOR CO LTD

AI summary

An object is to provide a catalyst particle that can exhibit high activity. The catalyst particle is an alloy particle formed of platinum atom and a non-platinum metal atom, wherein (i) the alloy particle has an L12 structure as an internal structure and has an extent of ordering of L12 structure in the range of 30 to 100%, (ii) the alloy particle has an LP ratio calculated by CO stripping method of 10% or more, and (iii) the alloy particle has a dN/dA ratio in the range of 0.4 to 1.0.