Fuel Cell Catalyst Layer Inhibiting Ir Oxide Elution
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Solution Overview
Problem
Fuel cell catalyst layers with Pt and Ir oxide particles experience reduced water electrolysis function due to Ir oxide elution when exposed to high anode potential, as both catalysts are supported on the same substrate with similar particle sizes, leading to increased area-to-weight ratios and subsequent elution.
Innovation Solution
A catalyst layer with Pt particles supported on carbon substrates and Ir oxide particles, where the mean primary crystallite diameter of Ir oxide particles is 100.0 nm to 500.0 nm, and the ratio of Ir oxide to Pt particle diameters is 20.0 or greater, reducing the area-to-weight ratio of Ir oxide particles and inhibiting elution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Ir oxide particles are used as water electrolysis catalyst with similar size to Pt particles, then catalytic activity is improved, but Ir oxide elution occurs under high anode potential leading to reduced water electrolysis function
Solution Approach 1:
The patent changes the size parameter of Ir oxide particles from being similar to Pt particles (conventional) to being significantly larger (20 times or more in diameter). This parameter change reduces the area-to-weight ratio of Ir oxide particles, thereby inhibiting elution under high anode potential while maintaining water electrolysis catalytic activity.
2Area of stationary object
If small particle sizes are used for both Pt and Ir oxide, then catalytic surface area is increased, but area-to-weight ratio increases leading to increased elution
Solution Approach 1:
The patent selectively changes the size parameter of Ir oxide particles while keeping Pt particle size small. By making Ir oxide particles 20 times or more in diameter compared to Pt particles, the patent achieves a lower area-to-weight ratio for Ir oxide, reducing elution while Pt maintains high catalytic activity due to its small size and large surface area.
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 solution effectively inhibits the reduction in water electrolysis function by preventing Ir oxide elution, maintaining performance even under high anode potential conditions, while also optimizing hydrogen oxidation and ionomer content for improved overall fuel cell performance.
Implementation Method 1
Catalysts comprising anode side catalyst layers include hydrogen oxidation catalysts and water electrolysis catalysts
Implementation Method 2
Ir oxide particles as a water electrolysis catalyst
Data Source
AI summary
There is provided a catalyst layer for a fuel cell that can inhibit reduction in water electrolysis function. The catalyst layer for a fuel cell according to this disclosure comprises carbon supports on which Pt particles are supported, and Ir oxide particles, wherein the ratio of the mean primary particle size of the Ir oxide particles with respect to the mean primary particle size of the Pt particles is 20 or greater. The mean primary particle size of the Pt particles may be 20.0 nm or smaller and the mean primary particle size of the Ir oxide particles may be 100.0 nm to 500.0 nm.