Supercritical CO2 Catalyst Deposition on Crystalline Carbon Supports
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Solution Overview
Problem
The challenge of carbon corrosion in fuel cells and water electrolysis devices due to the use of carbon supports with high crystallinity, which complicates catalyst synthesis and reduces durability, is addressed by using a supercritical fluid method to disperse catalytic metals uniformly on carbon supports with high crystallinity.
Innovation Solution
A method involving the preparation of a mixed solution with a surface stabilizer, additive, carbon support, and catalytic metal precursor, followed by increasing pressure and temperature to create a supercritical state using carbon dioxide, and maintaining this state to uniformly disperse the catalytic metal on the carbon support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon support with high crystallinity is used to suppress carbon corrosion, then durability is improved, but synthesis difficulty increases due to insufficient defects for catalyst supporting
Solution Approach 1:
The patent changes the physical state parameters of carbon dioxide from gaseous or liquid to supercritical state (temperature above 31.1°C and pressure above 73.8 bar), which fundamentally alters its solvation and diffusion properties. This parameter change enables the supercritical fluid to penetrate the highly crystalline carbon support structure and uniformly distribute metal precursors, resolving the synthesis difficulty while maintaining the high crystallinity needed for durability
Solution Approach 2:
The patent introduces a surface stabilizer as an intermediary substance that mediates between the metal precursor and the carbon support. The surface stabilizer adsorbs onto the carbon support surface and provides binding sites for metal precursors, enabling catalyst supporting on highly crystalline carbon that lacks natural defects. This intermediary resolves the contradiction by creating artificial anchoring points without compromising the carbon support's crystalline structure
2Ease of manufacture
If conventional methods are used to disperse metal on carbon support, then synthesis is simpler, but metal dispersion uniformity is poor
Solution Approach 1:
The patent employs supercritical carbon dioxide fluid dynamics to achieve uniform metal dispersion. The supercritical fluid penetrates the carbon support through pressure-driven flow, carrying metal precursors deep into the support structure. The high diffusivity and low viscosity of the supercritical fluid ensure uniform distribution throughout the porous network, achieving manufacturing precision that conventional liquid or gaseous methods cannot attain
Solution Approach 2:
The patent utilizes the phase transition of carbon dioxide to supercritical state and back to extract the catalyst. The phase transition to supercritical state enables penetration and uniform distribution, while the subsequent phase transition back to liquid or gas phase during depressurization leaves the metal uniformly dispersed on the carbon support. This phase transition mechanism ensures both synthesis feasibility and dispersion uniformity
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 method enables the formation of catalytic metals with high dispersion and stability on carbon supports, maintaining performance over 800 cycles without significant particle size change, enhancing the durability and efficiency of fuel cells and secondary batteries.
Implementation Method 1
uses carbon dioxide in a supercritical state having the characteristics of a gas, such as high diffusion rate, low viscosity and surface tension
Implementation Method 2
high diffusion rate
Implementation Method 3
increasing the pressure and temperature of the chamber to create a supercritical state
Data Source
AI summary
The present disclosure relates to a method for preparing a catalyst using a supercritical fluid and a catalyst produced thereby. According to the present disclosure, a catalyst wherein a catalytic metal is uniformly dispersed on a carbon support with high crystallinity and complex structure can be prepared using carbon dioxide in a supercritical state having the characteristics of a gas, such as high diffusion rate, low viscosity and surface tension, and the characteristics of a liquid, such as high density and solubility.