Copper-Iron Zeolitic Catalyst for NOx Conversion and N2O Reduction
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Solution Overview
Problem
Existing catalysts for selective catalytic reduction of NOx do not meet stringent Euro 7 regulations and fail to effectively limit N2O emissions while maintaining good NOx conversion and thermal stability.
Innovation Solution
A catalyst comprising a substrate coated with a zeolitic material, copper, and a non-zeolitic oxidic material containing iron and aluminum, with specific ratios and compositions to enhance NOx conversion and reduce N2O formation across a wide temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If copper-based SCR catalysts are used to achieve good NOx conversion, then NOx conversion is improved, but N2O emissions increase and thermal stability deteriorates
Solution Approach 1:
The patent employs a composite catalyst structure combining zeolitic material (CHA framework) with copper and iron-containing non-zeolitic oxidic material. This composite approach allows the zeolite framework to provide thermal stability and selective catalytic sites, while the copper and iron components work synergistically to reduce N2O formation during NOx conversion, resolving the contradiction between high NOx conversion and low N2O emissions
Solution Approach 2:
The catalyst exhibits different functional zones: the zeolitic material provides thermal stability and structural framework, while the copper and iron-containing non-zeolitic material provides catalytic activity for NOx reduction and N2O suppression. This local differentiation of material properties allows simultaneous optimization of NOx conversion and N2O reduction
2Productivity
If copper-based SCR catalysts are used to achieve good NOx conversion, then NOx conversion is improved, but thermal stability deteriorates
Solution Approach 1:
The zeolitic material (CHA framework) serves as a thermally stable structural framework that maintains its integrity at high temperatures, while the copper and iron-containing non-zeolitic oxidic material provides the catalytic functionality. This composite structure allows the catalyst to achieve good NOx conversion while maintaining thermal stability through the zeolite framework
Solution Approach 2:
The catalyst structure separates thermal stability functions (performed by the zeolitic framework) from catalytic activity functions (performed by the copper and iron-containing non-zeolitic material). This functional separation allows the catalyst to maintain thermal stability while achieving high NOx conversion efficiency
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 catalyst achieves high NOx conversion and reduced N2O formation, demonstrating improved thermal stability and compliance with stringent emission regulations.
Implementation Method 1
catalyst for the selective catalytic reduction of NOx comprising a substrate having an inlet end, an outlet end, a substrate axial length extending from the inlet end to the outlet end and a plurality of passages defined by internal walls of the substrate extending therethrough; a coating comprising a zeolitic material, copper and a first non-zeolitic oxidic material comprising iron and aluminum
Data Source
AI summary
The present invention relates to a catalyst for the selective catalytic reduction of NOx comprising a substrate having an inlet end, an outlet end, a substrate axial length extending from the inlet end to the outlet end and a plurality of passages defined by internal walls of the substrate extending therethrough; and a coating comprising a zeolitic material, copper and a first non-zeolitic oxidic material comprising iron and aluminum, wherein at least 25 weight-% of the first non-zeolitic oxidic material consists of iron, calculated as Fe2O3.