Core-Shell Electrode Catalyst Halogen Impurity Control
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Solution Overview
Problem
Conventional electrode catalysts for polymer electrolyte fuel cells (PEFCs) face challenges in achieving sufficient catalytic activity and longevity due to high levels of chlorine and bromine impurities, with existing methods focusing primarily on chlorine removal and neglecting the impact of bromine on catalyst performance.
Innovation Solution
The development of an electrode catalyst with a core-shell structure, where the concentrations of chlorine and bromine species are reduced to 900 ppm or lower and 400 ppm or lower, respectively, measured by X-ray fluorescence, to enhance catalytic activity and reduce manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrode catalysts are used with standard purification methods, then manufacturing process is simple, but chlorine and bromine impurity content remains high causing catalyst corrosion and short fuel cell life
Solution Approach 1:
The patent applies preliminary action by performing multiple washing steps with deionized water during the catalyst synthesis process to remove chlorine and bromine impurities before the catalyst is used in fuel cells. This preliminary purification prevents subsequent corrosion and performance degradation, extending fuel cell life while maintaining a relatively simple manufacturing process.
Solution Approach 2:
The patent changes the purification parameters by specifying multiple washing steps with deionized water having specific resistivity requirements (≥10 MΩ·cm). This parameter control ensures thorough removal of halogen impurities without requiring complex purification equipment, thus improving reliability while keeping manufacturing simple.
2Reliability
If chlorine-free and bromine-free starting materials are used, then impurity content is reduced improving catalytic activity, but manufacturing cost increases due to stricter material specifications
Solution Approach 1:
The patent applies the extraction principle by specifically removing chlorine and bromine impurities through multiple washing steps with deionized water. This targeted extraction of harmful elements improves catalytic activity and fuel cell durability without requiring expensive chlorine-free and bromine-free starting materials, thus maintaining cost-effectiveness while achieving high reliability.
Solution Approach 2:
The patent converts the potential harm of using conventional starting materials (which may contain chlorine and bromine) into a benefit by implementing a washing process that removes these impurities. This approach allows the use of readily available, cost-effective starting materials while achieving the same catalytic performance as would be obtained with expensive pure materials.
3Ease of manufacture
If core-shell structure with reduced noble metal content is adopted, then manufacturing cost is reduced, but catalytic activity may be compromised without proper impurity control
Solution Approach 1:
The patent employs a core-shell structure where a non-noble metal core (such as iron oxide or manganese oxide) is combined with a noble metal shell (platinum or platinum alloy). This composite structure reduces noble metal content and manufacturing cost while the multiple washing steps ensure low impurity content, maintaining high catalytic activity and fuel cell 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 catalyst exhibits sufficient catalytic activity and durability while reducing manufacturing costs by minimizing noble metal content, particularly by reducing bromine and chlorine impurities, thereby improving the overall performance and lifespan of PEFCs.
Implementation Method 1
an electrode catalyst having a core-shell structure including: a support; a core part formed on the support; and a shell part formed to cover at least a part of a surface of the core part
Implementation Method 2
the concentration of bromine (Br) species is not higher than 400 ppm when measured by X-ray fluorescence (XRF) spectroscopy, and the concentration of chlorine (Cl) species is not higher than 900 ppm when measured by X-ray fluorescence (XRF) spectroscopy
Data Source
Figure 1~2
Figure 3~4
Figure 5A~5B
AI summary
Provided is an electrode catalyst in which the contents of chlorine (Cl) species and bromine (Br) species are reduced to a predetermined level or lower, capable of exhibiting sufficient catalyst performance. The electrode catalyst has a core-shell structure including a support, a core part formed on the support and a shell part formed to cover at least a part of the surface of the core part. A concentration of bromine (Br) species of the electrode catalyst as measured by X-ray fluorescence (XRF) spectroscopy is 400 ppm or less, and a concentration of chlorine (Cl) species of the electrode catalyst as measured by X-ray fluorescence (XRF) spectroscopy is 900 ppm or less.