Surface-Modified Catalyst Precursors for Diesel Aftertreatment
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Solution Overview
Problem
There is a need for high durability and easily synthesizable catalysts in diesel engine aftertreatment systems to effectively reduce emissions, particularly in harsh environments where existing catalysts may degrade.
Innovation Solution
A method involving the use of surface-modified metal oxides, zeolites, and vanadium oxides, achieved by mixing an organic solvent with organometallic compounds and calcining the mixture to create catalysts with enhanced durability and efficiency, such as niobium pentoxide modified with yttrium stabilized ceria or zirconia, which can be applied to washcoat formulations for improved emissions control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional catalysts are used in diesel aftertreatment systems, then the system can reduce emissions, but the catalysts degrade in harsh environments resulting in reduced durability
Solution Approach 1:
The patent applies composite materials by combining metal oxides (such as ceria, zirconia, alumina) with specific surface area characteristics and pore size distributions to create a composite catalyst structure. This composite approach enhances catalyst durability in harsh diesel exhaust environments while maintaining emission reduction effectiveness, directly resolving the technical contradiction between reliability and environmental degradation.
2Reliability
If complex catalyst synthesis methods are used to improve catalyst performance, then catalyst efficiency increases, but the manufacturing process becomes more difficult
Solution Approach 1:
The patent employs parameter changes by optimizing specific physical parameters of the metal oxide supports, including surface area (50-500 m²/g), pore size (5-50 nm), and particle diameter (1-10 μm). By controlling these parameters within specific ranges, the patent achieves high catalyst efficiency through simplified synthesis procedures, resolving the contradiction between catalyst performance and manufacturing ease.
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 surface-modified catalysts demonstrate increased durability, improved NOx reduction efficiency, and enhanced urea hydrolysis efficiency, leading to more effective emissions control and reduced deposit formation in diesel engine exhaust systems.
Implementation Method 1
calcining the mixture to provide a surface-modified metal oxide catalyst
Implementation Method 2
surface-modified catalyst precursors for diesel engine aftertreatment applications
Data Source
AI summary
The present disclosure features a method of making an engine aftertreatment catalyst, where the engine aftertreatment catalyst includes a metal oxide, a metal zeolite, and/or vanadium oxide when the metal oxide is different from vanadium oxide, each of which can be independently surface-modified with a surface modifier. The method includes providing a solution including an organic solvent and an organometallic compound; mixing the solution with a metal oxide, a metal zeolite, and/or a vanadium oxide to provide a mixture; drying the mixture; and calcining the mixture to provide a surface-modified metal oxide catalyst, a surface-modified metal zeolite catalyst, and/or a surface-modified vanadium oxide catalyst. The organometallic compound can be, for example, a metal alkoxide, a metal carboxylate, a metal acetylacetonate, and/or a metal organic acid ester.