Titanium Oxide Carrier Catalyst Heat Treatment for Low Fuel Cell Resistance
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Solution Overview
Problem
Fuel cells with existing carrier metal catalysts have high internal resistance, which hinders efficient energy transfer and requires a solution to reduce this resistance for improved performance.
Innovation Solution
A carrier metal catalyst is developed with titanium oxide fine particles doped with a valence-different element, where the metal fine particles are supported on a carrier powder with a specific structure and heat-treated at 920 to 1100°C to achieve a mean particle size of 3 to 10 nm, optimizing the Ti3+ region for enhanced conductivity and reducing internal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If heat treatment is carried out at 900°C or lower, then the structure of the carrier metal catalyst is maintained, but the cell resistance remains high (0.10 Ω·cm2 or higher)
Solution Approach 1:
The patent applies parameter changes by optimizing the heat treatment temperature to a specific range (920-1100°C) to transform the titanium oxide support structure. This temperature parameter change creates Ti3+ regions that enhance electrical conductivity, reducing cell resistance to 0.090 Ω·cm2 or lower while maintaining catalyst stability through controlled phase transformation.
Solution Approach 2:
The patent utilizes phase transitions of titanium oxide during heat treatment. The controlled heating process induces phase changes in the titanium oxide support, creating conductive Ti3+ regions that improve electron transport. This phase transition mechanism directly addresses the high resistance problem while preserving the catalytic functionality.
2Reliability
If heat treatment temperature exceeds 1100°C, then conductivity increases, but metal fine particles aggregate and become large, decreasing catalyst performance
Solution Approach 1:
The patent applies parameter changes by defining an optimal heat treatment temperature range (920-1100°C) that balances conductivity enhancement with particle size control. Within this range, the titanium oxide undergoes sufficient phase transformation to create conductive pathways without causing excessive metal particle aggregation, maintaining both electrical performance and catalytic activity.
Solution Approach 2:
The patent employs partial action by applying heat treatment at temperatures that are sufficient to create the necessary Ti3+ regions for conductivity but controlled to avoid excessive particle growth. This partial thermal treatment achieves the minimum required conductivity improvement without over-processing that would cause particle aggregation and performance degradation.
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 achieves a cell resistance of 0.090 Ω·cm2 or lower, significantly improving the fuel cell's conductivity and reducing internal resistance, thereby enhancing its performance.
Implementation Method 1
the carrier fine particles are doped with an element having a valence different from a valence of titanium
Implementation Method 2
When the tetravalent titanium (Ti4+) in the titanium oxide (TiO2) is reduced to Ti3+, conductivity is obtained
Implementation Method 3
after allowing the metal colloidal particles to be adsorped onto the support
Implementation Method 4
when the heat treatment after allowing the metal colloidal particles to be adsorped onto the support is carried out at a temperature of 920° C. or higher, the area of Ti3+ becomes larger
Implementation Method 5
When the tetravalent titanium (Ti4+) in the titanium oxide (TiO2) is reduced to Ti3+, conductivity is obtained
Implementation Method 6
the carrier fine particles comprise a chained portion structured by a plurality of crystallites being fusion bonded to form a chain
Data Source
AI summary
The carrier metal catalyst achieves suppression of internal resistance of a fuel cell. A carrier metal catalyst includes: a carrier powder; and metal fine particles supported on the carrier powder; wherein: the carrier powder is an aggregates of carrier fine particles; the carrier fine particles includes a chained portion structured by a plurality of crystallites being fusion bonded to form a chain; the carrier fine particles include titanium oxide; the carrier fine particles are doped with an element having a valence different from a valence of titanium; the titanium oxide of the carrier powder has an anatase phase/rutile phase ratio of 0.2 or lower; the metal fine particles have a mean particle size of 3 to 10 nm; the metal fine particles include platinum; and a cell resistance measured under standard conditions of a fuel cell prepared using the carrier metal catalyst is 0.090 Ωcm·2 or lower.