Nitride Support for Stable High-Potential Fuel Cell Electrodes
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Solution Overview
Problem
Current electrode catalysts for polymer electrolyte fuel cells (PEFC) face challenges with carbon degradation under frequent load changes and high electric potentials, requiring improved conductivity and specific surface area, while existing nitride and oxide supports often result in reduced catalyst performance due to low conductivity and surface coverage issues.
Innovation Solution
A nitride particulate support with a chain or dendritic structure is developed, formed through a high-temperature flame process, which maintains high conductivity and specific surface area, allowing for stable support of platinum or platinum alloys with controlled nano-scale particle diameters, and is resistant to corrosion at high potentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If metal oxide particles are made into fine particles to enlarge specific surface area, then catalyst performance is improved, but contact resistance increases and electric conductivity decreases
Solution Approach 1:
The patent combines multiple oxide particles (specifically metal oxide particles) to form aggregated particles with chain or dendritic structures. This merging approach increases the specific surface area while maintaining good contact between particles, thereby preserving electric conductivity. The aggregated structure allows particles to be closely connected, reducing contact resistance compared to dispersed fine particles.
Solution Approach 2:
The patent creates composite oxide particles by aggregating multiple metal oxide particles together. These composite aggregated particles possess both high specific surface area (due to the fine nature of constituent particles) and good electric conductivity (due to the intimate contact in aggregated structure). The composite nature allows simultaneous achievement of both contradictory properties.
2Area of stationary object
If oxide and nitride powder are made into fine particles, then specific surface area increases, but contact between powder bodies becomes point contact and contact resistance increases
Solution Approach 1:
The patent merges fine oxide and nitride particles into aggregated structures where particles are closely connected. This merging transforms the point contact situation into extended contact areas, reducing contact resistance while preserving the high specific surface area benefit of fine particles.
3Reliability
If carbon is used as support for platinum catalyst, then catalyst performance is provided, but carbon degrades due to oxidation reaction at high potential
Solution Approach 1:
The patent changes the material parameter of the catalyst support from carbon to oxide particles (such as metal oxides). This parameter change replaces the unstable carbon material with oxidation-resistant oxide materials, eliminating the degradation issue while maintaining catalytic functionality. The oxide support provides the necessary stability at high potentials where carbon would oxidize.
4Duration of action of stationary object
If metal oxide is used as support to prevent carbon deterioration, then durability is improved, but conductivity is low and specific surface area is not large
Solution Approach 1:
The patent merges multiple metal oxide particles to form aggregated particles with chain or dendritic structures. This merging increases the specific surface area compared to individual particles while the aggregated structure maintains good inter-particle contact for conductivity. The result is a support that provides both durability (from oxide material) and sufficient conductivity/surface area (from aggregated structure).
Solution Approach 2:
The patent creates composite aggregated oxide particles that combine the durability of metal oxides with enhanced surface area and conductivity properties. The composite structure allows the material to simultaneously achieve long-term stability and sufficient electrochemical performance.
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 nitride support enhances the stability and durability of the electrode catalyst, maintaining high catalytic activity and preventing degradation at potentials of 0.9 V or more, enabling long-term stable operation and widespread use of PEFCs.
Implementation Method 1
Patent Literature 8 discloses an inorganic oxide support which suppresses the grain growth of metals supported thereby
Implementation Method 2
a nitride structure having a certain specific composition and crystal structure is formed by a certain high temperature place, for example, a flame method
Data Source
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AI summary
Disclosed is an oxide and/or nitride support for electrode catalysts, which is used for electrodes for polymer electrolyte fuel cells (PEFC). The support for electrode catalysts is an aggregation body of primary particles of oxide of at least one kind of metal selected from rare earths, alkaline earths, transition metals, niobium, bismuth, tin, antimony, zirconium, molybdenum, indium, tantalum, and tungsten, and the aggregation body is configured such that at least 80% of the metal oxide primary particles having a size of 5 nm to 100 nm aggregate and bind each other to form dendritic or chain structures each of which is made of 5 or more of the metal oxide primary particles.