Pt-on-Carbon Cathode Catalyst With Tuned d-Band Center
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Solution Overview
Problem
The existing catalysts for solid polymer fuel cells face challenges in maintaining initial activity and durability due to environmental changes during operation, with current evaluation methods limited to bulk or filmy platinum, failing to effectively assess particulate platinum or platinum alloy oxygen reduction activity.
Innovation Solution
The development of catalyst particles with platinum or platinum alloys supported on carbon powder, where the d band center is regulated between 2.90 eV and 3.85 eV, and the ratio of zerovalent platinum is maintained at 75% or higher, optimizing the bonding property between platinum and oxygen for enhanced oxygen reduction activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional evaluation methods are used for bulk or filmy platinum, then existing catalyst assessment approaches can be maintained, but they fail to effectively assess particulate platinum or platinum alloy oxygen reduction activity
Solution Approach 1:
The invention changes the evaluation parameters from bulk/film properties to particle-specific properties by introducing d band center energy (Ec) and zerovalent platinum ratio as key parameters. This allows accurate assessment of particulate platinum catalysts that conventional methods cannot evaluate, directly resolving the measurement precision issue for new catalyst forms.
2Reliability
If platinum catalysts are used without electron state regulation, then catalyst manufacturing is simpler, but initial activity and durability are insufficient due to environmental changes during operation
Solution Approach 1:
The invention regulates the electron state parameters (d band center Ec and zerovalent platinum ratio) of platinum catalysts to specific ranges. This parameter control improves catalyst reliability and durability by optimizing the bonding property between platinum and oxygen, while the regulation methods maintain manufacturing feasibility through controlled synthesis conditions.
Solution Approach 2:
The invention utilizes carbon powder carriers with porous structures to support platinum catalyst particles. The porous carbon matrix provides high surface area for catalyst dispersion and facilitates mass transport, contributing to both initial activity and durability without significantly complicating the manufacturing process.
3Productivity
If the d band center is not regulated, then catalyst synthesis is less complex, but the bonding property between platinum and oxygen is suboptimal, reducing oxygen reduction activity
Solution Approach 1:
The invention optimizes the d band center energy (Ec) parameter of platinum to enhance the bonding property with oxygen, directly improving oxygen reduction reaction productivity. The regulation is achieved through controlled synthesis conditions and material composition, balancing the productivity gain with manageable synthesis complexity.
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
This approach results in improved catalytic activity and durability by adjusting the electron state of platinum on the catalyst surfaces, ensuring favorable oxygen reduction reactions and sustained performance over time.
Implementation Method 1
catalyst particles including platinum or platinum alloy are supported on a carbon powder carrier... excellent in activity as a catalyst for cathodes (air electrodes) for solid polymer fuel cells
Implementation Method 2
power is generated by means of electrochemical oxidation and reduction reactions taking place at the electrodes
Implementation Method 3
a bond energy (Ec) at a gravity center position is 2.90 eV or more and 3.85 eV or less as calculated from a spectrum area of a Pt5d orbit-derived spectrum... optimizing the bonding property between platinum and oxygen
Data Source
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AI summary
The present invention relates to a catalyst for solid polymer fuel cells in which catalyst particles including platinum or platinum alloy are supported on a carbon powder carrier. The catalyst of the present invention is a catalyst for solid polymer fuel cells in which the bond energy (Ec) at a gravity center position is 2.90 eV or more and 3.85 eV or less as calculated from a spectrum area of a Pt5d orbit-derived spectrum which is obtained by measuring a valence band spectrum in a range of 0 eV or more and 20 eV or less in the result of subjecting the catalyst particles to X-ray photoelectron spectroscopic analysis.