Axial Cu-Fe Zeolite SCR Catalyst for Low N2O Diesel NOx Control

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Solution Overview

Problem

Existing SCR catalysts struggle to achieve high NOx conversion while minimizing N2O emissions under both standard and fast SCR gas feed conditions, failing to meet stringent emission targets set by modern diesel engines.

Innovation Solution

A process for preparing a catalyst involving a coating of iron and copper zeolitic material on a substrate, where the zeolitic material is applied in specific axial lengths with precise calcination steps, optimizing the distribution of copper and iron to enhance catalytic performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single zeolitic material is used in the SCR catalyst, then the catalyst structure is simple, but it cannot simultaneously achieve high NOx conversion and low N2O emissions under both standard and fast SCR conditions

Engineering Contradiction:

Improvecatalytic performance under different gas feed conditionsVSAvoidcatalyst composition

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines two different zeolitic materials (Cu-CHA and Fe-ZSM-5) into a single catalyst composition. The Cu-CHA component provides high NOx conversion under standard SCR conditions, while the Fe-ZSM-5 component suppresses N2O formation under fast SCR conditions. This merging of two specialized materials into one composite catalyst resolves the contradiction by achieving multi-condition performance without requiring separate catalyst systems.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The composite zeolitic material performs multiple functions simultaneously: Cu-CHA handles standard SCR conversion while Fe-ZSM-5 controls N2O emissions during fast SCR events. This multi-functionality allows a single catalyst to adapt to different operating conditions (standard and fast SCR) without requiring structural changes or additional components, thus resolving the versatility-complexity contradiction.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If iron and copper zeolitic materials are combined in one catalytic system, then both NOx conversion and N2O formation are improved, but the manufacturing process becomes more complex

Engineering Contradiction:

Improveemission control performanceVSAvoidcatalyst preparation process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by pre-forming two separate zeolitic materials (Cu-CHA and Fe-ZSM-5) with specific compositions and properties before combining them. This allows each component to be optimized independently for its specific function (NOx conversion and N2O suppression) while simplifying the final combination process. The pre-prepared materials are then impregnated onto the substrate in a controlled sequence, making the manufacturing process manageable despite the complexity of the final catalyst structure.

Inventive Principle:

Principle #10Preliminary action

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 significantly reduces N2O emissions while maintaining or improving NOx conversion levels, effectively addressing the challenges of modern diesel engine emissions.

Implementation Method 1

a coating comprising iron and a zeolitic material comprising copper... the catalyst for the selective catalytic reduction of nitrogen oxide

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 2

the catalyst significantly reduces N2O emissions while maintaining or improving NOx conversion levels

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 3

calcining the substrate having the first aqueous mixture disposed thereon, obtaining a substrate comprising a coating comprising a zeolitic material comprising copper

Methodology Applied

Scientific EffectThermal treatment: Heat Treatment

Data Source

PatentUS12569810B2Selective catalytic reduction catalyst and a process for preparing a selective catalytic reduction catalyst

Publication Date: 2026.03.10 BASF MOBILE EMISSIONS CATALYSTS LLC

AI summary

The present invention relates to a process for preparing a catalyst for the selective catalytic reduction of nitrogen oxide comprising, among other steps, preparing a second aqueous mixture comprising water and an iron salt; and disposing the second mixture on the substrate obtained according to (ii), comprising a coating comprising a zeolitic material comprising copper, over y % of the substrate axial length from the inlet end to the outlet end of the substrate, wherein y is in the range of from 10 to x, obtaining a substrate comprising, in a first zone, the coating comprising a zeolitic material comprising copper and over y % of the substrate axial length an iron salt; and, if x>y, in a second zone extending from y % to x % of the substrate axial length from the inlet end to the outlet end, the coating comprising a zeolitic material comprising copper.