Mesoporous Pt-Alloy Electrocatalyst for Fuel Cell Durability
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Solution Overview
Problem
Fuel cells face challenges in maintaining both initial performance and durability due to the ionization and dissolution of transition metals in catalysts, particularly when the ratio of platinum to transition metals is not optimized, leading to poor durability and low initial performance.
Innovation Solution
An electrocatalyst with a carbon support and a catalyst alloy of platinum and a transition metal, where the mesopore has a specific average effective diameter and transition metal ratio varying between regions, allowing for controlled desorption of transition metals to maintain high initial performance and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the ratio of transition metal in the catalyst is increased to reduce cost, then the cost decreases, but the initial performance of the fuel cell becomes low
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the catalyst alloy particles have a platinum-rich outer shell and a transition metal-rich core. This spatial differentiation allows the outer shell to provide high initial performance and corrosion resistance, while the inner core provides catalytic activity and cost benefits. The non-uniform distribution of metals within the particle structure resolves the contradiction between initial performance and durability.
2Reliability
If the catalyst contains large amounts of transition metal to improve durability, then the durability increases, but the transition metal is likely to be ionized and dissolved under fuel cell operation
Solution Approach 1:
The patent uses the platinum shell as an intermediary protective layer that surrounds the transition metal core. This platinum shell acts as a barrier that prevents direct contact between the transition metal and the corrosive fuel cell environment, thereby preventing ionization and dissolution of the transition metal. The intermediary platinum layer allows the transition metal to be present in high amounts for durability and cost benefits while protecting it from harmful chemical reactions.
3Ease of manufacture
If a single ratio of platinum to transition metal is used in the catalyst, then the manufacturing is simplified, but it is difficult to ensure both initial performance and durability
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the catalyst alloy particles have a platinum-rich outer shell and a transition metal-rich core. This spatial differentiation allows the outer shell to provide high initial performance and corrosion resistance, while the inner core provides catalytic activity and cost benefits. The non-uniform distribution of metals within the particle structure resolves the contradiction between initial performance and durability.
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 electrocatalyst ensures both high initial performance and durability of fuel cells by preferentially desorbing transition metals from the alloy supported outside the mesopore throat, maintaining performance post-durability tests.
Implementation Method 1
preferentially desorbing transition metals from the alloy supported outside the mesopore throat
Implementation Method 2
generates electrical energy by electrochemical reaction between fuel gas (e.g., hydrogen) and oxidant gas (e.g., oxygen)
Data Source
AI summary
To provide an electrocatalyst for fuel cells, which is configured to ensure both the initial performance and durability of fuel cells. An electrocatalyst for fuel cells, wherein the electrocatalyst comprises a carbon support including a mesopore and a catalyst alloy supported on the carbon support, and the catalyst alloy is a catalyst alloy of platinum and a transition metal; wherein the mesopore includes at least one throat; wherein an average effective diameter of the at least one throat is 1.8 nm or more and less than 3.2 nm; and wherein a transition metal ratio of the catalyst alloy supported on a deeper-side region than the at least one throat, is lower than the transition metal ratio of the catalyst alloy supported on a nearer-side region than the at least one throat.