Oxygen Reduction Catalyst with Metal Oxide Composite Carrier
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Solution Overview
Problem
Fuel cells using existing oxygen reduction catalysts lack durability during start-stop operations due to oxidation corrosion of carbon carriers, leading to decreased power generation performance.
Innovation Solution
A composite oxygen reduction catalyst comprising carbon, Group 4 metal elements, nitrogen, and oxygen, with dispersed particles of Group 4 metal elements and optionally iron group elements, supported with noble metals, is developed, featuring a specific thermogravimetry-differential thermal analysis (TG-DTA) pattern and improved durability through a production process involving heat treatment and oxidation steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If carbon black is used as a carrier to support platinum catalyst, then catalytic activity is improved, but resistance to high potential corrosion is worsened
Solution Approach 1:
The patent employs a composite material structure where platinum catalyst particles are supported on a composite carrier consisting of carbon black combined with metal oxides (such as TiO2, SiO2, Al2O3, or ZnO). This composite carrier structure combines the high surface area and conductivity of carbon black with the corrosion resistance of metal oxides, thereby maintaining catalytic activity while improving resistance to high potential corrosion during fuel cell start-stop operations.
2Power
If conventional catalysts are used, then initial performance is achieved, but start-stop durability is worsened
Solution Approach 1:
The composite carrier structure of carbon black combined with metal oxides provides both the electrical conductivity and surface area needed for high initial performance, while the metal oxide component specifically protects against corrosion during repeated start-stop cycles, thereby achieving both high initial performance and improved start-stop durability.
Solution Approach 2:
The patent applies different materials with different properties to different functional requirements: carbon black provides electrical conductivity and surface area for catalytic activity, while metal oxides provide corrosion resistance specifically at the carrier-catalyst interface and in the high potential environment, creating localized functional zones that collectively solve the durability problem.
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 excellent start-stop durability and initial performance in fuel cells, with reduced carbon oxidation corrosion and enhanced conductivity, outperforming conventional catalysts in durability tests.
Implementation Method 1
a production process involving heat treatment and oxidation steps
Implementation Method 2
a production process involving heat treatment and oxidation steps
Implementation Method 3
thermogravimetry-differential thermal analysis (TG-DTA) pattern
Implementation Method 4
thermogravimetry-differential thermal analysis (TG-DTA) pattern
Data Source
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AI summary
An oxygen reduction catalyst includes a composite particle, the composite particle including a carbon structure and particles each including a Group 4 metal element M1, the composite particle containing a Group 4 metal element M1, carbon, nitrogen and oxygen, the particles each including a Group 4 metal element M1 being dispersed in the carbon structure, and the composite particle having a percentage of mass loss (a) and a percentage of mass loss (b), which are represented by specific formulae, of not more than 15% and 25 to 70%, respectively.