Pt Alloy Fuel Cell Catalyst With Hydrophilic Carbon for Low Pt Elution
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Solution Overview
Problem
Fuel cell catalysts using Pt alloy particles face impaired activity due to Pt elution into solvents during electrode production, hindering the investigation of improved activity and durability.
Innovation Solution
A fuel cell catalyst with Pt alloy particles and hydrophilic groups, where the catalyst has 0.65 mmol/g or more of hydrophilic groups and an elution amount of Pt 0.625 mg or less per gram when immersed in sulfuric acid, is produced by carrying Pt alloy particles on a carbon powder carrier and treating with an oxidizing and reducing agent to suppress Pt elution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrophilic groups are introduced into the fuel cell catalyst to improve initial activity and low humidity performance, then catalyst activity is improved, but Pt is eluted into the solvent resulting in impaired catalyst activity
Solution Approach 1:
The patent changes the chemical parameters of the carbon carrier by controlling the amount and type of hydrophilic groups introduced through oxidation treatment. By optimizing the oxidation conditions and selecting specific oxidizing agents, the patent achieves the right balance between hydrophilicity (for improved activity) and Pt stability (reduced elution).
Solution Approach 2:
The patent creates a composite structure where Pt alloy particles are supported on oxidized carbon carriers with specific hydrophilic group compositions. This composite approach allows the carbon carrier to provide both the mechanical support and the hydrophilic environment needed for high catalyst activity, while the Pt alloy composition is optimized to resist elution.
2Reliability
If Pt alloy particles are used as catalyst particles to improve catalyst activity, then activity is enhanced, but Pt elution occurs leading to impaired performance
Solution Approach 1:
The patent optimizes the compositional parameters of the Pt alloy particles by selecting specific alloying elements and ratios. This parameter optimization enhances the intrinsic activity of the catalyst while improving the stability of Pt against elution into the solvent during electrode production and operation.
3Ease of manufacture
If the fuel cell catalyst is immersed in sulfuric acid solution during electrode production, then electrode formation occurs, but Pt elutes into the solvent
Solution Approach 1:
The patent applies preliminary protective measures by introducing hydrophilic groups onto the carbon carrier surface before electrode production. This pre-treatment creates a protective interface that prevents Pt elution during the subsequent sulfuric acid immersion step, allowing easy electrode manufacture without Pt loss.
4Reliability
If hydrophilic groups are introduced to maintain catalyst performance in low humidity state, then low humidity performance is improved, but Pt elution increases
Solution Approach 1:
The patent precisely controls the concentration and chemical nature of hydrophilic groups on the carbon carrier. By optimizing this parameter, the catalyst maintains high performance in low humidity conditions while the Pt alloy composition and carrier structure work together to minimize Pt elution.
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 achieves improved activity and performance at low humidity while maintaining high activity over long periods, with reduced Pt elution, enhancing the durability and efficiency of the fuel cell.
Implementation Method 1
contacting the catalyst particle-carrying carbon powder with an oxidizing agent to impart hydrophilic groups to the catalyst particle-carrying carbon powder
Implementation Method 2
contacting the fuel cell catalyst precursor with a reducing agent to prepare a fuel cell catalyst
Data Source
AI summary
A catalyst for fuel cells that contains a carbon powder carrier and catalyst particles carried on the carbon powder carrier, the catalyst particles being Pt alloy particles, the catalyst for fuel cells having 0.65 mmol/g or more of hydrophilic groups, and a Pt elution amount when 0.5 g of the catalyst for fuel cells is immersed in 30 ml of a 0.5 mol/L aqueous sulfuric acid solution and retained for 100 hours at room temperature under stirring being 0.625 mg or less per g of the catalyst for fuel cells.