Multi-Layer Exhaust Catalyst with Graded Precious Metal Distribution

Solution Overview

Problem

Existing catalysts for treating exhaust gases containing nitrogen monoxide, carbon monoxide, and volatile organic compounds require increased amounts of expensive precious metals to enhance oxidation power, leading to higher production costs.

Innovation Solution

A catalyst with multiple layers, where the upper layer is richer in precious metals and the lower layer is poorer, is produced by coating a substrate with a slurry of porous inorganic compounds, allowing for enhanced oxidation power without increasing the overall precious metal content, using a colloidal solution of precious metals supported on a porous inorganic compound with specific particle size and distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the amount of precious metal (Pt) is increased to enhance oxidation power, then the catalytic activity is improved, but the production cost increases

Engineering Contradiction:

Improveoxidation powerVSAvoidamount of precious metal

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies local quality by creating a multi-layered coat structure where the precious metal concentration varies by layer. The upper layer (4-30 μm) is richer in precious metal to provide high catalytic activity at the exhaust gas interface, while the lower layer (20-100 μm) is poorer in precious metal to reduce overall cost. This spatial differentiation of metal concentration optimizes both performance and cost-effectiveness.

Inventive Principle:

Principle #3Local quality

2Reliability

If the amount of precious metal is increased to enhance oxidation power, then the catalytic activity is improved, but the production cost increases

Engineering Contradiction:

Improveoxidation powerVSAvoidproduction cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies local quality by creating a multi-layered coat structure where the precious metal concentration varies by layer. The upper layer (4-30 μm) is richer in precious metal to provide high catalytic activity at the exhaust gas interface, while the lower layer (20-100 μm) is poorer in precious metal to reduce overall cost. This spatial differentiation of metal concentration optimizes both performance and cost-effectiveness.

Inventive Principle:

Principle #3Local quality

3Reliability

If a single uniform layer is used, then the manufacturing process is simple, but the oxidation power is insufficient without increasing precious metal content

Engineering Contradiction:

Improveoxidation powerVSAvoidcoat layer structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the coat layer into multiple distinct layers with different precious metal concentrations. The upper layer (4-30 μm) contains higher precious metal content for catalytic activity, while the lower layer (20-100 μm) contains lower precious metal content. This segmentation allows optimization of oxidation power without requiring uniform high metal content throughout the entire coat structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by creating a multi-layered coat structure where the precious metal concentration varies by layer. The upper layer (4-30 μm) is richer in precious metal to provide high catalytic activity at the exhaust gas interface, while the lower layer (20-100 μm) is poorer in precious metal to reduce overall cost. This spatial differentiation of metal concentration optimizes both performance and cost-effectiveness.

Inventive Principle:

Principle #3Local quality

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 enhanced oxidation power with a smaller amount of precious metals, improving catalytic activity and reducing production costs while maintaining effectiveness in treating exhaust gases from industrial sources.

Implementation Method 1

a carrier which includes a porous inorganic compound

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

an active component composed of one or more precious metals

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 3

the coat layers are made up of a plurality of layers, an upper layer of which is richer in an active component composed of one or more precious metals and a lower layer of which is poorer in such an active component

Methodology Applied

Scientific EffectConcentration gradient:

Implementation Method 4

by coating the surface of a substrate with a slurry of a porous inorganic compound, followed by drying

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS8501133B2Catalyst for treating exhaust gases, method for producing the same, and method for treating exhaust gases

Publication Date: 2013.08.06 MITSUBISHI POWER LTD

AI summary

A catalyst for treating exhaust gases containing nitrogen monoxide, carbon monoxide and volatile organic compounds includes a plurality of layers, an upper layer of which has an active component contained uniformly therein and a lower layer of which has no active component contained therein. The catalyst is obtained through the steps of: forming the lower layer by coating the surface of substrate with a slurry of a porous inorganic compound, followed by drying; and forming the upper layer, which is to be the top surface of the catalyst, by coating the surface of the lower layer with a slurry of a porous inorganic compound that has the active component composed of one or more precious metals supported thereon, followed by drying. The oxidation power of the resulting catalyst is enhanced without increasing the amount of precious metal supported thereon.