Layered Catalyst Reduces PGM Usage via Segmentation
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Solution Overview
Problem
Current catalyst systems for treating engine exhaust gases, which contain pollutants like hydrocarbons, carbon monoxide, and nitrogen oxides, rely heavily on platinum group metals (PGM) due to inefficiencies and poisoning issues when using base metals, leading to high costs and suboptimal performance.
Innovation Solution
A layered catalytic article comprising a nickel component supported on ceria and a platinum group metal component supported on an oxygen storage and alumina component, with a specific weight percentage distribution, is used to reduce PGM usage while maintaining emission control efficiency, employing a process involving slurry deposition and calcination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If base metals are used to replace platinum group metals in catalysts, then cost is reduced, but catalytic efficiency and thermal stability deteriorate
Solution Approach 1:
The catalyst is divided into two distinct layers: a first layer containing nickel component supported on ceria for cost-effective base metal catalysis, and a second layer containing platinum group metal component supported on oxygen storage and alumina components for high-efficiency catalytic action. This segmentation allows each layer to perform its specialized function, achieving both cost reduction and maintained catalytic efficiency.
Solution Approach 2:
The invention creates a composite catalyst structure combining different metal components (nickel and platinum group metals) with different support materials (ceria and oxygen storage/alumina components) in a layered configuration. This composite approach leverages the advantages of both base metals (cost-effectiveness) and PGMs (catalytic efficiency) while mitigating their individual disadvantages.
2Quantity of substance
If base metals are added to catalysts to reduce PGM usage, then cost is reduced, but PGM gets poisoned and catalytic efficiency decreases
Solution Approach 1:
By separating the base metal component (nickel in first layer) and PGM component (in second layer) into distinct layers, the invention prevents harmful interactions between them. The physical separation eliminates the poisoning effect while maintaining the cost benefits of base metal usage.
3Reliability
If PGM-based TWC catalysts are used to achieve desired emission control efficiency, then catalytic performance is improved, but cost increases
Solution Approach 1:
The layered structure segments the catalytic function between two layers: the first layer with nickel component handles certain catalytic transformations at lower cost, while the second layer with PGM component provides high-efficiency catalytic action for emission control. This segmentation reduces overall PGM usage while maintaining required emission control efficiency.
Solution Approach 2:
The invention replaces expensive PGMs with cheaper base metals (nickel) in the first layer for catalytic functions that can be effectively performed by base metals, reducing the overall quantity of expensive PGMs required in the system while maintaining acceptable performance.
4Reliability
If copper is added to the nickel-ceria layer, then certain catalytic properties are improved, but thermal stability deteriorates
Solution Approach 1:
The invention removes copper from the nickel-ceria first layer, creating a copper-free composition that achieves thermal stability. The layer is configured to provide desired catalytic properties through nickel and ceria without relying on copper, thereby eliminating the thermal stability issue associated with copper-containing formulations.
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 approach significantly reduces PGM usage while achieving efficient conversion of hydrocarbons, carbon monoxide, and nitrogen oxides, meeting stringent emission regulations with improved thermal stability and catalytic performance.
Implementation Method 1
a first layer comprising a nickel component supported on a ceria component
Implementation Method 2
a second layer comprising a platinum group metal component supported on an oxygen storage component
Implementation Method 3
an alumina component, wherein the platinum group metal component comprises platinum, rhodium, palladium
Implementation Method 4
calcination at a temperature ranging from 400 to 700° C.
Data Source
AI summary
The presently claimed invention provides a layered catalytic article comprising a first layer comprising a nickel component and a ceria component, wherein the amount of the nickel component is 1.0 to 50 wt. %, calculated as nickel oxide, based on the total weight of the first layer, and wherein the first layer is essentially free of copper; a second layer comprising a platinum group metal component, an oxygen storage component, and an alumina component, wherein the platinum group metal component comprises platinum, rhodium, palladium, or any combination thereof, and wherein the amount of the platinum group metal component is 0.0 to 5 wt. %, based on the total weight of the second layer; and a substrate. The presently claimed invention also provides a process for preparing the layered catalytic article. It further provides an exhaust system for internal combustion engines comprising a layered catalytic article.