Porous Carbon Catalyst Carrier With Low Crystallized Material
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Solution Overview
Problem
Conventional carbon materials for catalyst carriers in polymer electrolyte fuel cells have low yield during classification treatments, leading to increased production costs and reduced mechanical strength, due to the presence of coarse, crystalline, and nonporous materials.
Innovation Solution
A carbon material with a controlled acetylene-to-silver nitrate molar ratio during synthesis to minimize the formation of crystallized material, resulting in a porous carbon with a specific surface area, mesopore volume, and dendritic structure that enhances yield and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional carbon materials are used as catalyst carriers, then the catalyst layer can be formed, but the yield during classification treatment is low due to presence of coarse crystallized material
Solution Approach 1:
The patent changes the chemical composition parameters of the carbon material by controlling the acetylene gas blowing amount during synthesis. By optimizing the acetylene-to-silver nitrate molar ratio to 0.3-0.5, the patent minimizes formation of crystallized material while maintaining the dendritic structure and porosity required for catalyst carrier functionality. This parameter optimization directly improves classification treatment yield from 80-90% to 95% or higher.
2Manufacturing precision
If the acetylene gas blowing amount is increased to consume unreacted silver ions, then the reaction completeness improves, but the formation of crystallized material increases reducing yield
Solution Approach 1:
The patent identifies and optimizes the critical parameter of acetylene gas blowing amount. By setting the acetylene-to-silver nitrate molar ratio to 0.3-0.5, the patent achieves the optimal balance between reaction completeness and crystallized material formation. This precise parameter control ensures sufficient reaction while preventing excessive acetylene from forming soot that crystallizes into coarse particles.
3Quantity of substance
If porous carbon material with large specific surface area is used to increase catalyst carrying capacity, then the catalyst utilization rate increases, but the mechanical strength decreases
Solution Approach 1:
The patent applies local quality by creating a hierarchical structure where the dendritic framework provides mechanical strength at the macro level while the porous branches provide high surface area at the micro level. The controlled porosity and dendritic morphology allow different regions of the material to serve different functions: the backbone structure maintains integrity while the branched porous regions maximize catalyst attachment sites.
Solution Approach 2:
The patent creates a composite structure combining the dendritic carbon framework with catalyst metal particles. The carbon material serves as a composite carrier that integrates structural support functions with high surface area functions, allowing simultaneous achievement of mechanical strength and high catalyst carrying capacity through the synergistic combination of structural and functional properties.
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 approach significantly improves the yield of the classification treatment, maintains required characteristics for fuel cell performance, and reduces production costs by minimizing coarse particle rejection.
Implementation Method 1
a decomposition step of causing a self-decomposing and explosive reaction of the silver acetylide to yield a carbon material intermediate
Implementation Method 2
a washing treatment step of bringing the carbon material intermediate into contact with a nitric acid solution to clean the carbon material intermediate
Implementation Method 3
a heat treatment step of heat-treating the cleaned carbon material intermediate in a vacuum, or an inert gas atmosphere at a temperature of from 1400 to 2100° C. to yield a carbon material for use as a catalyst carrier
Data Source
AI summary
A carbon material for use as a catalyst carrier for a polymer electrolyte fuel cell which is a porous carbon material and satisfies at the same time (1) the content of a crystallized material is 1.6 or less, (2) the BET specific surface area obtained by a BET analysis of a nitrogen gas adsorption isotherm is from 400 to 1500 m2/g, (3) the cumulative pore volume V2-10 with respect to a pore diameter of from 2 to 10 nm obtained by an analysis of a nitrogen gas adsorption isotherm using the Dollimore-Heal method is from 0.4 to 1.5 mL/g, and (4) the nitrogen gas adsorption amount Vmacro between a relative pressure of 0.95 and 0.99 in a nitrogen gas adsorption isotherm is from 300 to 1200 cc (STP)/g, and the method of producing the same.