Pre-aged Ceria NOx Trap Catalyst Regeneration
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Solution Overview
Problem
NOx traps with high oxygen storage capacity require longer regeneration lengths, which is inefficient, and existing technologies do not effectively reduce this capacity while maintaining NOx activity.
Innovation Solution
A NOx trap catalyst with a first layer containing pre-aged ceria and a second layer with high surface area ceria, reducing the oxygen storage capacity by pre-aging the ceria-containing material before incorporation, thereby enhancing NOx activity and regeneration efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If fresh ceria-containing material is used in the NOx trap catalyst, then high oxygen storage capacity is achieved, but regeneration length becomes excessively long
Solution Approach 1:
The ceria-containing material is pre-aged before being incorporated into the NOx trap catalyst. This preliminary aging action reduces the oxygen storage capacity of the ceria material in advance, so that when the catalyst is installed, it already has reduced OSC without requiring extended regeneration periods. The pre-aging process is performed during manufacturing rather than during vehicle operation.
2Loss of time
If pre-aged ceria-containing material is used to reduce oxygen storage capacity, then regeneration length is shortened, but NOx activity may be compromised
Solution Approach 1:
The invention changes the physical and chemical parameters of the ceria-containing material through controlled pre-aging processes. By adjusting aging time, temperature, and atmospheric conditions, the oxygen storage capacity parameter is reduced while maintaining sufficient catalytic activity for NOx management. The pre-aging process modifies the crystal structure and surface properties of ceria to achieve the desired balance.
3Quantity of substance
If high surface area ceria is used, then oxygen storage capacity increases, but regeneration efficiency decreases
Solution Approach 1:
The invention modifies the surface area and particle size distribution parameters of the ceria-containing material through controlled milling and aging processes. By optimizing these parameters, the material achieves sufficient oxygen storage capacity while maintaining high regeneration efficiency. The pre-aging process creates a controlled surface morphology that facilitates efficient oxygen release during regeneration.
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 NOx trap catalyst achieves significant reduction in oxygen storage capacity, leading to shorter regeneration lengths and maintaining NOx activity, improving the efficiency of exhaust gas treatment systems.
Implementation Method 1
the first ceria-containing material is pre-aged prior to incorporation into the first layer
Implementation Method 2
the NO2 is adsorbed by the NOx adsorbent in the form of an inorganic nitrate
Implementation Method 3
nitric oxide reacts with oxygen to produce NO2 in the presence of the oxidation catalyst
Implementation Method 4
the stored inorganic nitrates decompose to form NO or NO2 which are then reduced to form N2 by reaction with carbon monoxide, hydrogen and/or hydrocarbons in the presence of the reduction catalyst
Data Source
AI summary
A NOx trap catalyst is disclosed. The NOx trap catalyst comprises a first layer, the first layer comprising a first ceria-containing component having a surface area of less than 80 m2/g; a Ba/Ce/magnesium-aluminate spinel; platinum; palladium; and alumina; and a second layer, the second layer comprising a second ceria-containing component having a higher surface area than the first ceria-containing material present in the first layer; rhodium; and alumina.The invention also includes an exhaust system comprising the NOx trap catalyst, and a method for treating exhaust gas utilizing the NOx trap catalyst.