Pt-Ru Zirconia Methane Oxidation Catalyst for Sulfur Resistance

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Solution Overview

Problem

Existing methane oxidation catalysts struggle with high methane oxidation activity and resistance to sulfur poisoning, particularly in the exhaust gases from natural gas-fueled engines.

Innovation Solution

A methane oxidation catalyst comprising multi-crystalline zirconia, platinum, and ruthenium, with a specific ratio of platinum to ruthenium and optionally a chloride component, is prepared by mixing and calcining zirconia powder with platinum and ruthenium precursors, enhancing activity and resistance to sulfur poisoning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing methane oxidation catalysts are used, then methane oxidation activity can be achieved, but resistance to sulfur poisoning is poor

Engineering Contradiction:

Improveresistance to sulfur poisoningVSAvoidsulfur compound deactivation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The catalyst employs a composite structure combining multi-crystalline zirconia support with a bimetallic platinum-ruthenium system. This composite architecture synergistically integrates the high surface area and thermal stability of multi-crystalline zirconia with the catalytic activity and sulfur resistance of the Pt-Ru alloy, achieving both high methane oxidation activity and enhanced resistance to sulfur poisoning that neither component could provide alone

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention optimizes specific parameters including the platinum-to-ruthenium mass ratio (1:1 to 10:1), calcination temperature (450-650°C), and zirconia crystal phase composition (monoclinic, tetragonal, and cubic phases). These parameter optimizations create a catalyst structure that maintains high catalytic activity while developing resistance to sulfur compound deactivation

Inventive Principle:

Principle #35Parameter changes

2Productivity

If high methane oxidation activity is achieved, then conversion efficiency improves, but susceptibility to sulfur poisoning increases

Engineering Contradiction:

Improvemethane oxidation activityVSAvoidstability in sulfur-containing environment

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The multi-crystalline zirconia support acts as an intermediary between the platinum-ruthenium catalytic sites and the sulfur-containing exhaust environment. The zirconia's high surface area provides dispersed metal sites for methane oxidation while its crystal structure and surface properties intercept and mitigate sulfur compound interactions, protecting the active metal sites from poisoning while maintaining high catalytic productivity

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If single-phase zirconia is used, then catalyst preparation is simpler, but catalytic activity and sulfur resistance are reduced

Engineering Contradiction:

Improvecatalyst preparation complexityVSAvoidcatalyst performance stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The invention utilizes controlled calcination temperature parameters (450-650°C) to generate multi-crystalline zirconia with specific phase compositions from precursor materials. By optimizing this thermal processing parameter, the catalyst achieves the beneficial multi-phase crystal structure that enhances both activity and sulfur resistance while maintaining a relatively simple preparation process

Inventive Principle:

Principle #35Parameter changes

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 exhibits high methane oxidation activity and maintains performance even in the presence of sulfur compounds, effectively converting methane to carbon dioxide and water, making it suitable for treating exhaust gases from natural gas-fueled engines.

Implementation Method 1

catalytically oxidizing the methane to carbon dioxide and water before the discharge of the engine exhaust gas

Methodology Applied

Scientific EffectCatalytic oxidation: Catalysis

Implementation Method 2

oxidizing the methane to carbon dioxide and water

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 3

The zirconium oxide is in the form of monoclinic crystal phase and includes no more than 10 mass % that is in the tetragonal and cubic crystal forms

Methodology Applied

Scientific EffectCrystalline phase structure: Crystallisation

Implementation Method 4

The impregnated zirconium oxide is dried and then fired at a temperature of from 450 to 650° C.

Methodology Applied

Scientific EffectThermal treatment: Heat Treatment

Data Source

PatentUS12486792B2Methane oxidation catalyst and a method of making and using thereof

Publication Date: 2025.12.02 SHELL OIL CO

AI summary

A sulfur-resistant, high activity methane oxidation catalyst for use in removing methane from gas streams having a concentration of methane by oxidizing the methane. The methane oxidation catalyst is especially useful in processing gas streams that also have a concentration of a sulfur compound. The sulfur-resistant methane oxidation catalyst includes a unique multi-crystalline zirconia as a support for a platinum component and a ruthenium component. The multi-crystalline zirconia contributes to the excellent properties of the catalyst. The platinum and ruthenium components can be included in the methane oxidation catalyst in a specific weight ratio that also contributes to the enhanced properties of the catalyst. The sulfur-resistant methane oxidation catalyst may also include a chloride component that contributes to enhanced properties of the catalyst.