Segmented Catalytic Article with Barrier Layer
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Solution Overview
Problem
Existing catalysts for reducing carbon monoxide, hydrocarbon, and nitrogen oxide emissions in exhaust gases face challenges such as deactivation due to reaction with alumina, low thermal stability, and poisoning of platinum group metals (PGM) by base metals like nickel and copper.
Innovation Solution
A catalytic article comprising a first layer with nickel and copper supported on ceria, and a second layer with a platinum group metal component supported on an oxygen storage component, alumina, or zirconia, separated by a barrier layer or gap, is developed to enhance emission reduction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If nickel or copper is used as catalyst component, then CO reduction efficiency is improved, but catalyst deactivation occurs due to reaction with alumina forming nickel-aluminate and copper-aluminate
Solution Approach 1:
The catalyst is divided into multiple functional layers: a first layer containing nickel and copper components for CO reduction, and a second layer containing PGM components for HC and NOx reduction. This segmentation allows each layer to perform its specific function while preventing harmful interactions between different metal components.
Solution Approach 2:
A barrier layer or gap is introduced between the first layer (nickel/copper) and the second layer (PGM). This intermediary structure prevents direct contact between base metals and PGM, avoiding poisoning effects while maintaining the beneficial catalytic activities of both layers.
2Productivity
If base metals (nickel, copper) are added to enhance CO oxidation, then CO reduction efficiency is improved, but PGM poisoning occurs and thermal stability decreases
Solution Approach 1:
The catalyst structure is segmented into distinct layers where base metals are confined to the first layer and PGM to the second layer. This physical separation ensures that base metals enhance CO oxidation without coming into contact with and poisoning the PGM.
Solution Approach 2:
The barrier layer acts as an intermediary that physically isolates the base metal-containing first layer from the PGM-containing second layer, preventing poisoning while allowing both components to function optimally in their respective zones.
3Device complexity
If alumina is used as support material, then catalyst structure is provided, but nickel and copper react with alumina causing catalyst deactivation
Solution Approach 1:
The catalyst is structured as multiple layers with the first layer containing nickel and copper components that are protected from direct reaction with alumina. The barrier layer prevents alumina from contacting and deactivating the base metal components while still providing structural support.
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 catalytic article significantly reduces carbon monoxide, hydrocarbon, and nitrogen oxide emissions, meeting stringent regulatory standards while maintaining the stability and effectiveness of the platinum group metals.
Implementation Method 1
a first layer comprising a nickel component and a copper component supported on a ceria component
Implementation Method 2
functions to stimulate the oxidation reaction of HC and CO
Implementation Method 3
a second layer comprising a platinum group metal component supported on at least one of an oxygen storage component, an alumina component and a zirconia component
Implementation Method 4
the reduction of NOx
Implementation Method 5
supported on a ceria component, wherein the amount of the nickel component is 0.1 to 30 wt. %, calculated as nickel oxide, based on the total weight of the first layer
Data Source
AI summary
The present invention provides a catalytic article comprising a) a first layer comprising a nickel component and a copper component supported on a ceria component, wherein the amount of the nickel component is 0.1 to 30 wt. %, calculated as nickel oxide, based on the total weight of the first layer, and wherein the amount of the copper component is 0.01 to 5.0 wt. % calculated as copper oxide, based on the total weight of the first layer; b) a second layer comprising a platinum group metal component supported on at least one of an oxygen storage component, an alumina component and a zirconia 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 0.01 to 5.0 wt. % based on the total weight of the second layer; and c) a substrate, wherein the first layer and the second layer are separated by a barrier layer or a gap.