Core-Shell Electrode Catalyst with Tungsten Carbide Core
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Solution Overview
Problem
Current electrode catalysts for fuel cells, particularly those with a core-shell structure containing tungsten compounds, lack sufficient catalyst activity and durability compared to conventional Pt/C catalysts, and there is a need to reduce platinum usage to lower costs.
Innovation Solution
A catalyst structure with a core part containing W carbide and a two-layered shell part, where the first shell is made of simple Pd and the second shell of simple Pt, supported on an electrically conductive carbon, enhancing catalyst activity and durability while reducing platinum usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a core-shell catalyst particle with Pd or Pd alloy core and Pt shell is used to reduce platinum amount, then the noble metal cost is reduced, but the catalyst activity and durability are insufficient compared to conventional Pt/C catalysts
Solution Approach 1:
The patent applies a nested core-shell structure where a Pd or Pd alloy core is surrounded by a Pt shell, creating a hierarchical arrangement that maximizes Pt utilization. The Pt shell thickness is controlled to be 0.5-5 nm, forming a protective layer that maintains catalytic activity while reducing overall Pt content compared to conventional Pt/C catalysts.
Solution Approach 2:
The invention uses composite materials by combining Pd or Pd alloy with Pt in a core-shell configuration. This composite structure leverages the high catalytic activity of Pd in the core while using a thin Pt shell to maintain surface reactivity, achieving both cost reduction and performance maintenance.
2Quantity of substance
If W oxide or W-based materials are used as core part to reduce Pt usage, then the noble metal cost is reduced, but the catalyst activity and durability remain insufficient
Solution Approach 1:
The patent changes the core material from conventional Pd or Pd alloy to W oxide or W-based materials, altering the compositional parameters of the core-shell structure. This parameter change aims to reduce Pt usage while maintaining or improving catalyst performance through the unique properties of tungsten-based core materials.
Solution Approach 2:
The invention applies local quality by using W oxide or W-based materials specifically in the core region, while maintaining a Pt shell on the surface. This spatial differentiation allows the core to provide structural stability and reduce Pt content, while the Pt shell ensures high catalytic activity at the reaction interface.
3Reliability
If Pt/C catalyst with high Pt support rate (50 wt%) is used, then the catalyst activity and durability are sufficient, but the preparation cost is high
Solution Approach 1:
The patent replaces expensive Pt/C catalyst with a core-shell structure using Pd or Pd alloy core with Pt shell, effectively substituting some expensive noble metal with cheaper alternative materials while maintaining catalytic functionality. This reduces the overall noble metal content and preparation cost.
Solution Approach 2:
The invention changes the catalyst composition parameters by reducing Pt content from 50 wt% in conventional Pt/C to a controlled Pt shell thickness of 0.5-5 nm in the core-shell structure, thereby reducing noble metal quantity while maintaining sufficient catalytic activity and durability through the optimized shell structure.
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 proposed catalyst structure achieves catalyst activity and durability at a practically durable level, contributing to lower costs by minimizing platinum usage and improving performance compared to conventional Pt/C catalysts.
Implementation Method 1
a core part containing a W carbide
Implementation Method 2
supported on an electrically conductive carbon
Implementation Method 3
a first shell part formed on the core part and made of simple Pd, and a second shell part formed on the first shell part and made of simple Pt
Data Source
AI summary
To provide electrode catalyst which has the catalyst activity and durability at a practically durable level and contributes to lowering of the cost in comparison with the conventional Pt/C catalyst. The electrode catalyst has a support and catalyst particles supported on the support. The catalyst particle has the core part, the first shell part formed on the core part, and the second shell part formed on the first shell part. The core part contains W compound including at least W carbide, the first shell part contains simple Pd, and the second shell part contains simple Pt.