Porous Catalyst Layer with Nanocarbon Interlayer for PEFC Durability
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Solution Overview
Problem
Conventional carbon-supported catalyst layers in PEFCs suffer from corrosion and water flooding issues, particularly when exposed to humid conditions, leading to reduced durability and catalyst degradation, necessitating a catalyst layer with improved humidity robustness and reduced noble metal usage.
Innovation Solution
A porous catalyst layer is developed, comprising integrated noble metal sheets with a porous nanocarbon layer containing fibrous nanocarbon between them, optimizing the structure and composition to enhance humidity resistance and catalyst activity while minimizing noble metal usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If carbon-supported catalyst is used in PEFC, then catalyst activity is improved, but carbon support corrodes and catalyst dissolves leading to reduced durability
Solution Approach 1:
The patent extracts the carbon support from the catalyst layer structure, creating a carbonless catalyst layer. By removing the carbon support that causes corrosion, the catalyst can maintain its activity while avoiding the durability issues associated with carbon degradation and catalyst dissolution.
Solution Approach 2:
The patent creates a composite catalyst layer structure combining metal sheets with porous coatings containing catalyst particles. This composite structure provides both the mechanical stability and catalytic activity needed, while avoiding carbon support corrosion through the use of corrosion-resistant metal substrates and protective porous layers.
2Reliability
If carbonless catalyst layer is used to avoid corrosion, then durability is improved, but water flooding occurs and properties deteriorate in humid conditions
Solution Approach 1:
The patent employs porous coatings on metal sheets that provide controlled porosity to manage water transport. The porous structure allows for efficient water removal while maintaining catalyst accessibility, preventing water flooding in humid conditions while preserving the carbonless durability advantage.
Solution Approach 2:
The patent introduces porous coating materials as intermediaries between the metal support and the catalyst particles. These porous coatings act as mediators that facilitate water management and gas transport while protecting the catalyst and maintaining structural integrity in humid environments.
3Quantity of substance
If noble metal amount is reduced to lower cost, then cost is reduced, but catalyst activity and performance decrease
Solution Approach 1:
The patent segments the catalyst layer into multiple functional components: metal sheets providing structural support, porous coatings for water and gas management, and dispersed catalyst particles. This segmentation allows for optimized distribution of noble metals, concentrating them where most needed for catalytic activity while reducing overall noble metal content.
Solution Approach 2:
The patent applies local quality by creating regions with different properties within the catalyst layer. The porous coatings have specific porosity and composition tailored for water management, while catalyst particles are strategically positioned and sized to maximize activity. This localized optimization maintains high catalyst activity with reduced noble metal loading.
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 porous catalyst layer achieves high cell voltage, improved humidity robustness, and increased durability even with a reduced amount of noble metal, effectively addressing the challenges of corrosion and water flooding in PEFCs.
Implementation Method 1
a porous nanocarbon layer disposed between two adjacent noble metal-including sheets... effectively addressing the challenges of corrosion and water flooding
Implementation Method 2
a catalyst layer included in each electrode of the PEFC... generates electricity by an electrochemical reaction between fuel such as hydrogen and an oxidizing agent such as oxygen
Data Source
AI summary
According to an embodiment, a porous catalyst layer includes a metal portion including plural noble metal-including sheets stacked apart from each other, and a porous nanocarbon layer disposed between two adjacent noble metal-including sheets. The plural noble metal-including sheets in the metal portion have an integrated portion. The porous nanocarbon layer includes fibrous nanocarbon.