Oxide Core Platinum Shell Fuel Cell Catalysts
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Solution Overview
Problem
Current fuel cell technologies face challenges in reducing platinum usage due to high costs and instability issues, particularly with core-shell structured catalysts where the base metal in the core dissolves, and using more noble metals does not curtail costs effectively.
Innovation Solution
Development of catalyst particles with a stable oxide inner particle and a platinum outermost layer, where the inner particle has oxygen defects, allowing for a continuous platinum layer formation and improved catalytic activity and durability, while reducing precious metal usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If core-shell structured catalysts with base metal core and platinum shell are used, then catalytic activity is improved, but the base metal in the core dissolves causing instability and reduced durability
Solution Approach 1:
The invention replaces the expensive and unstable precious metal core with a cheap, stable oxide core (such as TiO2, SnO2, Ta2O5, or Nb2O5). The core is designed to be stable and non-dissolving, while the platinum is confined to a thin outer shell, effectively making the expensive platinum the 'sacrificial' component that maintains stability rather than the base metal core.
Solution Approach 2:
The invention creates a composite catalyst particle consisting of an oxide core combined with a platinum-containing shell. This composite structure leverages the stability and low cost of oxide materials for the core while utilizing the catalytic activity of platinum in the shell, achieving both durability and catalytic performance.
2Reliability
If more noble metals are used in the core to prevent dissolution, then stability is improved, but costs increase significantly
Solution Approach 1:
The invention uses cheap oxide materials (TiO2, SnO2, Ta2O5, Nb2O5) as the core instead of expensive noble metals. These oxides are abundant, stable, and cost-effective, eliminating the need to use expensive noble metals in the core while maintaining stability and preventing dissolution.
Solution Approach 2:
The invention changes the material parameter of the core from expensive noble metals to inexpensive stable oxides, fundamentally altering the cost structure while maintaining the stability requirement. This parameter change allows the core to be both stable and cost-effective.
3Shape
If acid treatment is used to form shells with differing composition, then catalyst structure is modified, but the process becomes difficult to control and causes hydrophilization and oxidation of the carbon support
Solution Approach 1:
The invention extracts the acid treatment step from the manufacturing process entirely. Instead of using acid to form the shell structure, the patent employs alternative methods such as deposition or other non-acidic processes to create the platinum-containing shell on the oxide core, thereby eliminating the harmful effects of acid treatment on the carbon support.
Solution Approach 2:
The invention introduces an oxide material as an intermediary between the core and the platinum shell, replacing the need for acid treatment. The oxide surface serves as a stable platform for forming the platinum-containing shell without requiring harsh chemical treatments, thus avoiding hydrophilization and oxidation of the carbon support.
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 approach achieves higher catalytic activity and durability than traditional platinum catalysts, with the ability to form a continuous platinum layer on oxygen-defective oxide surfaces, enabling efficient fuel cell performance at lower costs.
Implementation Method 1
at least the surfaces of the particles composed of the second oxide are reduced to a first oxide having oxygen defects and an outermost layer containing platinum formed by reduction of the platinum ions is formed on the first oxide
Implementation Method 2
by inducing electrochemical oxidation of the fuel, converts chemical energy directly into electrical energy
Data Source
AI summary
A catalyst particle is composed of an inner particle and an outermost layer that includes platinum and covers the inner particle. The inner particle includes on at least a surface thereof a first oxide having an oxygen defect.