Amorphous Metal Catalyst for Low-Temperature Water-Gas Shift
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Solution Overview
Problem
Current catalysts for the low-temperature water-gas shift reaction require high amounts of precious metals and lack stability and efficiency, particularly in removing carbon monoxide, which poisons fuel cell anodes and is a criterion pollutant.
Innovation Solution
A catalyst system where a substrate, such as cerium oxide, is treated to remove significant amounts of metallic crystalline particles, leaving behind a non-crystalline residue that retains catalytic activity, significantly reducing the amount of precious metals needed, such as gold or platinum, while maintaining reaction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high amounts of precious metals are used in catalysts for low-temperature water-gas shift reaction, then catalytic activity is improved, but cost increases and metal content decreases efficiency
Solution Approach 1:
The patent extracts and removes crystalline metal particles from the catalyst through selective leaching processes, retaining only the amorphous metal species that provide catalytic activity. This extraction of unnecessary crystalline structures enables significant reduction of precious metal content while maintaining catalytic performance for the water-gas shift reaction.
Solution Approach 2:
The patent changes the physical state parameter of the metal from crystalline to amorphous/non-crystalline form. This parameter change fundamentally alters the catalyst's metal content and structure, enabling reduced precious metal loading while preserving or enhancing catalytic activity through the unique properties of amorphous metal species on ceria support.
2Reliability
If conventional catalysts are used for CO removal, then catalytic function is achieved, but stability and efficiency are insufficient for long-term operation
Solution Approach 1:
The patent creates a composite catalyst system combining amorphous metal species with ceria oxide support. This composite structure leverages the synergistic effects between the amorphous metal and ceria, achieving both high stability and efficiency for CO conversion while maintaining performance over extended operation periods.
Solution Approach 2:
Instead of using conventional crystalline metal particles as the primary catalytic active sites, the patent inverts the approach by utilizing amorphous/non-crystalline metal species as the active catalytic phase. This inversion leads to improved stability and efficiency by avoiding the degradation issues associated with crystalline metal particles.
3Ease of manufacture
If crystalline metal particles are present in the catalyst, then metal content is high, but catalytic efficiency and cost-effectiveness are reduced
Solution Approach 1:
The patent converts the previously harmful presence of crystalline metal particles into a benefit by selectively removing them through leaching. The amorphous metal species that remain are actually more effective catalysts per unit mass, transforming the problem of high metal content into an opportunity for reduced metal loading with enhanced efficiency.
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 method achieves high catalytic activity and stability with a substantial reduction in precious metal content, making the catalyst more cost-effective and efficient for hydrogen production in fuel cells, and demonstrates long-term stability in cyclic operations.
Implementation Method 1
the low-temperature water-gas shift reaction (LTS), which is represented by the relation CO+H2OCO2+H2
Implementation Method 2
Ceria participates in redox reactions by supplying and removing oxygen
Data Source
AI summary
The invention contemplates a method of making a catalytic material, and uses of the material. The catalytic material is made by depositing catalytic metals, such as gold or platinum, on substrate materials, such as lanthanum-doped ceria or other oxides. The catalytic metal, which comprises both crystalline and non-crystalline structures, is treated, for example with aqueous basic NaCN solution, to leach away at least some of the crystalline metallic component. The remaining noncrystalline metallic component associated with the substrate exhibits catalytic activity that is substantially similar to the catalyst as prepared. The use of the catalyst in an apparatus such as a reactor or analytic instrument is contemplated, as is the use of the catalyst in efficient, cost-effective reactions, such as removal of carbon monoxide from fuel gases, for example by performing the water gas shift reaction.