Catalytically Active Particulate Filter with Ternary Nitride
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Solution Overview
Problem
Existing catalytically active particulate filters face issues with low porosity leading to high pressure drop and decreased efficiency, require high activation temperatures for NOx decomposition, and use costly materials unsuitable for high-temperature environments.
Innovation Solution
A catalytically active filter incorporating a ternary nitride catalyst, such as tantalum oxynitride or magnesium silicon nitride, combined with elements like gold, osmium, or cesium, which forms a high-porosity structure allowing efficient NOx decomposition at lower temperatures without impacting engine performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional catalytic materials are used in particulate filters, then catalytic activity is achieved, but porosity is low resulting in high pressure drop and decreased filtering efficiency
Solution Approach 1:
The patent employs a porous ceramic substrate as the filter structure, providing high porosity (typically 40-60%) that allows efficient exhaust gas flow with low pressure drop. The catalytic materials are deposited on this porous substrate rather than forming a dense composite structure, maintaining both catalytic activity and high filtering efficiency.
Solution Approach 2:
The patent uses composite structures combining ceramic substrates with catalytic coatings. The ceramic provides structural integrity and porosity, while the catalytic layer (containing precious metals or base metal oxides) provides catalytic activity. This composite approach resolves the contradiction between structural requirements and catalytic functionality.
2Reliability
If conventional catalytic materials are used, then catalytic decomposition of NOx is achieved, but high activation temperatures are required resulting in inefficient decomposition
Solution Approach 1:
The patent modifies catalytic parameters by using base metal oxides (such as MnOx, CuO, Fe2O3) combined with precious metals or molten salts. These compositional changes lower the activation temperature for NOx decomposition, enabling efficient catalysis at typical diesel exhaust temperatures without requiring excessive heat.
Solution Approach 2:
The patent employs oxidation-promoting materials and structures that facilitate the oxidation of NO to NO2, which then decomposes more readily on the catalyst surface. This accelerated oxidation pathway reduces the temperature threshold for effective NOx decomposition.
3Reliability
If conventional catalytic materials are used, then catalytic activity is achieved, but the materials are costly and/or unsuited for high temperature environments
Solution Approach 1:
The patent replaces expensive precious metals with base metal oxides (MnOx, CuO, Fe2O3, NiO, CoO) that are significantly cheaper and suitable for high-temperature diesel exhaust environments. While base metals may have shorter lifetimes, the patent optimizes their formulation and support structures to achieve acceptable durability at reduced cost.
Solution Approach 2:
The patent changes the material parameters by selecting base metals with appropriate melting points and thermal stability for diesel exhaust applications. The catalytic formulation is optimized to maintain activity at high temperatures (400-600°C) while using cost-effective materials, balancing thermal suitability with economic considerations.
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 filter achieves efficient NOx decomposition into environmentally friendly gases at lower temperatures, maintaining effectiveness in high-temperature environments without increasing pressure drop, thus enhancing engine performance and reducing costs.
Implementation Method 1
A catalyst containing a ternary nitride; and at least one of gold, osmium, iridium, palladium, rhodium, rhenium, ruthenium, or cesium
Data Source
AI summary
A catalyst is disclosed. The catalyst contains a ternary nitride and at least one of gold, osmium, iridium, palladium, rhodium, rhenium, ruthenium, or cesium. The catalyst may be used for a particulate filter in an engine exhaust treatment system.