Pd-Ru Alloy Catalyst Resists CO Poisoning

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Solution Overview

Problem

Palladium fine particles used as catalysts for exhaust gas purification suffer from performance deterioration due to poisoning by carbon monoxide, and rhodium is expensive, while existing catalysts using alloy fine particles have limitations in catalytic activity and production methods for Pd-Ru alloy fine particles are not effective in inhibiting homocoupling reactions in Suzuki-Miyaura cross-coupling.

Innovation Solution

Formation of a solid solution between palladium and ruthenium alloy fine particles, which are produced by maintaining a solution containing a protective agent, reducing agent, palladium compound, and ruthenium compound at a temperature higher than a predetermined temperature, resulting in high catalytic activity for oxidation and reduction reactions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If palladium fine particles are used as catalyst for exhaust gas purification, then catalytic activity is provided, but performance deteriorates due to poisoning by carbon monoxide

Engineering Contradiction:
Improvecatalyst performanceVSAvoidpoisoning by carbon monoxide
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention uses a Pd-Ru alloy composite material where palladium and ruthenium are combined at the atomic level. This composite structure allows the catalyst to maintain high catalytic activity while resisting poisoning by carbon monoxide, as the ruthenium component protects the palladium from deactivation

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention changes the chemical composition parameter by forming a solid solution alloy with specific Pd:Ru ratios (0.1:0.9 to 0.9:0.1). This parameter modification transforms the catalyst's resistance to CO poisoning while maintaining catalytic functionality

Inventive Principle:
Principle #35Parameter changes

2Reliability

If rhodium fine particles are used as catalyst, then catalytic activity is provided, but cost increases due to expensive material

Engineering Contradiction:
Improvecatalyst performanceVSAvoidcost
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The invention replaces expensive rhodium with a Pd-Ru alloy system that uses more abundant and cheaper palladium and ruthenium metals. The alloy achieves comparable or superior catalytic performance to rhodium at significantly lower material cost

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

By creating a Pd-Ru alloy composite, the invention achieves rhodium-level catalytic performance using cheaper constituent metals, eliminating the need for expensive rhodium while maintaining high catalyst activity

Inventive Principle:
Principle #40Composite materials

3Reliability

If conventional alloy fine particles are used as catalyst, then catalytic activity is provided, but homocoupling reaction cannot be inhibited in Suzuki-Miyaura cross-coupling

Engineering Contradiction:
Improvecatalyst activityVSAvoidhomocoupling reaction
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention modifies the catalyst's chemical composition by creating a solid solution alloy with specific Pd:Ru ratios. This compositional parameter change alters the catalyst's interaction with reaction intermediates, selectively promoting cross-coupling while suppressing homocoupling side reactions

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The solid solution structure creates local atomic environments where Pd and Ru atoms are distributed at the atomic level. This local structural quality provides specific active sites that favor cross-coupling reactions over homocoupling, enabling selective catalysis

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 Pd-Ru alloy fine particles exhibit enhanced catalytic activity for CO oxidation, NOx reduction, H2 oxidation, and hydrocarbon oxidation, outperforming individual Pd and Ru fine particles and their mixtures, and demonstrate effective catalytic performance in Suzuki-Miyaura cross-coupling reactions.

Implementation Method 1

palladium-ruthenium alloy fine particles in which palladium and ruthenium form a solid solution

Methodology Applied
Scientific EffectSolid solution formation:

Implementation Method 2

catalytic activity for oxidation reaction of carbon monoxide

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 3

catalytic activity for reduction reaction of nitrogen oxide

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 4

catalytic activity for oxidation reaction of hydrogen gas

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 5

catalytic activity for oxidation reaction of hydrocarbon

Methodology Applied
Scientific EffectCatalysis: Catalysis

Data Source

PatentEP2898945B1Catalyst using pd-ru solid-solution-type alloy particles
Publication Date: 2020.09.02 THE JAPAN SCI & TECH AGENCY
  • EP2898945B1 patent drawingFigure 1
  • EP2898945B1 patent drawingFigure 2
  • EP2898945B1 patent drawingFigure 3A~3B

AI summary

The catalyst disclosed is a catalyst including palladium-ruthenium alloy fine particles in which palladium and ruthenium form a solid solution. The palladium-ruthenium alloy fine particles used in this catalyst can be produced by a production method including the step of maintaining a solution containing a protective agent, a reducing agent, a palladium compound or palladium ions, and a ruthenium compound or ruthenium ions at a temperature equal to or higher than a predetermined temperature.