Core-Shell Pt-Pd Nanoparticles for Fuel Cell Catalysts
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Solution Overview
Problem
Current platinum electrocatalysts in fuel cells face limitations due to slow oxygen reduction kinetics and high platinum loading, leading to efficiency losses and high manufacturing costs.
Innovation Solution
Development of platinum-coated palladium or palladium alloy nanoparticles with atomically thin platinum layers, including submonolayers, monolayers, bilayers, or combinations, where the platinum is either zerovalent or partially charged, and the palladium core is coated with a platinum shell, reducing the need for high platinum loading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high platinum loading is used in fuel cell electrocatalysts, then catalytic activity for oxygen reduction is improved, but manufacturing cost increases significantly
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where only the outer shell surface is coated with platinum, while the core consists of cheaper alternative materials. This concentrates the platinum coating exactly where catalytic activity is needed (at the surface) rather than using bulk platinum throughout the entire catalyst particle, thereby reducing overall platinum loading while maintaining surface catalytic performance.
Solution Approach 2:
The patent employs composite materials by combining platinum with alternative metal cores (such as palladium, nickel, or other transition metals) to create core-shell composite electrocatalysts. This composite structure leverages the high catalytic activity of platinum at the surface while utilizing the cost-effective core materials to reduce overall platinum content, directly addressing the contradiction between catalytic activity and manufacturing cost.
2Productivity
If conventional platinum electrocatalysts are used, then oxygen reduction reactions can occur, but reaction kinetics are slow leading to efficiency losses
Solution Approach 1:
The patent applies parameter changes by modifying the electronic and geometric structure of the catalyst surface through the core-shell configuration. The interaction between the core material and the platinum shell alters the d-band center position and surface electronic structure, which changes the adsorption energy of oxygen intermediates and improves reaction kinetics. This parameter modification enables faster oxygen reduction rates and reduces overpotential losses compared to conventional platinum catalysts.
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 platinum-coated palladium or palladium alloy nanoparticles enhance oxygen-reducing catalytic activities while minimizing platinum usage, thereby improving fuel cell efficiency and reducing costs.
Implementation Method 1
platinum-coated particles useful as fuel cell electrocatalysts
Data Source
AI summary
The invention relates to platinum-coated particles useful as fuel cell electrocatalysts. The particles are composed of a noble metal or metal alloy core at least partially encapsulated by an atomically thin surface layer of platinum atoms. The invention particularly relates to such particles having a palladium, palladium alloy, gold alloy, or rhenium alloy core encapsulated by an atomic monolayer of platinum. In other embodiments, the invention relates to fuel cells containing these electrocatalysts and methods for generating electrical energy therefrom.