PGM-OSC Solid Solution Catalyst for Three-Way Conversion
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Solution Overview
Problem
Three-way conversion catalysts have a narrow operation window, making it difficult to simultaneously eliminate hydrocarbons, carbon monoxide, and nitrogen oxides from engine exhausts, and there is a need for thermally stable and cost-effective oxygen storage components.
Innovation Solution
A composite material comprising a solid solution of platinum group metals and rare earth metal oxides, such as palladium and cerium oxide, is formed through co-precipitation and calcination, which can be impregnated on a support material like alumina or ceria-zirconia, enhancing oxygen storage and mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional TWC catalysts use separate PGM and OSC components, then the catalyst structure is simpler and manufacturing is easier, but the operation window remains narrow and thermal stability is insufficient
Solution Approach 1:
The patent combines PGM and OSC into a single integrated solid solution component where PGM atoms are dispersed within the OSC crystal lattice. This merging eliminates the need for separate PGM and OSC layers, simplifying the overall catalyst structure while simultaneously achieving enhanced adaptability through the dual functionality of the solid solution component.
Solution Approach 2:
The patent employs composite materials by creating a solid solution that integrates PGM and OSC at the atomic level. The composite structure combines the catalytic activity of PGM with the oxygen storage capacity of OSC, resulting in a material that exhibits both properties simultaneously while maintaining thermal stability and expanding the operation window.
2Adaptability or versatility
If more OSC is added to enlarge the operation window, then the catalyst performance improves, but the cost increases substantially
Solution Approach 1:
By merging PGM and OSC into a solid solution, the patent creates a dual-functional component where a small amount of material provides both catalytic activity and oxygen storage capacity. This eliminates the need to add large quantities of separate OSC to achieve operation window expansion, as the integrated solid solution achieves both functions simultaneously with reduced material quantities.
Solution Approach 2:
The solid solution component serves multiple functions simultaneously: it provides catalytic activity through PGM, oxygen storage capacity through OSC, and enhanced thermal stability. This multi-functionality allows the catalyst to achieve an enlarged operation window without requiring substantial additions of dedicated OSC, as one component performs multiple roles.
3Reliability
If PGM and OSC are provided as separate components, then the catalyst manufacturing process is simpler, but thermal stability and interaction efficiency are reduced
Solution Approach 1:
The patent uses composite materials to create a solid solution where PGM and OSC are integrated at the atomic level within a single crystal lattice structure. This composite approach enhances thermal stability by creating a unified structure that resists degradation, while the manufacturing process remains feasible through conventional co-precipitation and calcination methods.
Solution Approach 2:
The patent applies parameter changes by controlling the synthesis conditions (pH, temperature, calcination parameters) to form the solid solution structure. These parameter adjustments enable the formation of the integrated PGM-OSC structure during manufacturing, maintaining ease of production while achieving enhanced thermal stability through the solid solution morphology.
4Productivity
If the TWC operates within a narrow air-to-fuel ratio window, then the catalyst structure can be simpler, but the efficiency of simultaneous pollutant elimination is reduced
Solution Approach 1:
The solid solution composite material provides both catalytic activity and oxygen storage capacity in one integrated component. This enables the catalyst to maintain high productivity for pollutant elimination across a broader air-to-fuel ratio range, as the composite structure can simultaneously perform oxidation and reduction reactions with improved adaptability to varying exhaust conditions.
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 composite material expands the operation window of three-way catalysts, improving the efficiency of pollutant reduction under varying engine conditions and reducing the reliance on costly oxygen storage components.
Implementation Method 1
The PGM and the rare earth metal oxide can be co-precipitated to form the solid solution
Implementation Method 2
Three-way conversion (TWC) catalysts are used in engine exhaust streams to catalyze the oxidation of the unburned hydrocarbons (HCs) carbon monoxide (CO) in the exhaust streams and also to catalyze the reduction of nitrogen oxides (NOx) to nitrogen
Implementation Method 3
The presence of an oxygen storage component (OSC) in a TWC catalyst allows oxygen to be stored during lean conditions to promote reduction of NOx adsorbed on the catalyst, and to be released during rich conditions to promote oxidation of HCs and CO adsorbed on the catalyst
Data Source
AI summary
The present disclosure provides catalytic materials and catalytic articles formed therewith. The catalytic materials particularly can include an oxygen storage component comprising a solid solution of at least one platinum group metal and at least one rare earth metal oxide. In one or more embodiments, catalytic materials can include a solid solution of a platinum group metal (e.g., palladium) and a mixed metal oxide (e.g., ceria/zirconia).