Platinum Catalyst Composition for Hydrothermal Sintering Resistance
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Solution Overview
Problem
Platinum-based catalysts face sintering issues under high-temperature hydrothermal aging conditions, making them unsuitable for conventional three-way conversion formulations, and existing support materials do not provide adequate high-temperature stability.
Innovation Solution
A catalyst composition is developed with platinum supported on a composite of ceria, alumina, and magnesia, with specific weight percentages of each component, to stabilize platinum dispersion and enhance catalyst performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If platinum is used in conventional three-way conversion formulations, then catalytic activity is achieved, but platinum sintering occurs under high-temperature hydrothermal aging conditions
Solution Approach 1:
The patent employs a composite support material consisting of ceria-alumina-magnesia instead of conventional single-material supports. This composite structure provides synergistic effects where ceria stabilizes platinum through strong metal-support interaction, alumina provides structural framework, and magnesia enhances hydrothermal stability. The composite prevents platinum sintering while maintaining catalytic activity under high-temperature aging conditions (900-1050°C).
Solution Approach 2:
Ceria acts as an intermediary material between platinum and the alumina-magnesia support. The ceria forms a stable interface that mediates the interaction between platinum and the support, preventing direct contact between platinum particles and the support structure that would lead to sintering. The ceria layer maintains platinum dispersion through strong Pt-CeO2 interaction while allowing necessary catalytic functions.
2Reliability
If ceria is used as a support material to prevent platinum sintering, then platinum stability is improved, but bulk ceria undergoes sintering upon high temperature aging
Solution Approach 1:
The patent creates a composite where ceria is combined with alumina and magnesia in specific ratios (20-40 wt% ceria, 10-80 wt% alumina, 10-80 wt% magnesia). This composite structure prevents bulk ceria sintering by distributing ceria within the alumina-magnesia matrix, which provides structural stability at high temperatures. The composite maintains the beneficial Pt-CeO2 interaction while preventing ceria particle growth through the stabilizing effect of the alumina-magnesia framework.
Solution Approach 2:
The patent applies local quality by having ceria primarily at the interface with platinum (where it provides stabilization) while the bulk support consists of the thermally stable alumina-magnesia composite. This spatial distribution allows ceria to perform its stabilizing function locally at the Pt-support interface without requiring the entire bulk material to be ceria, thereby preventing bulk ceria sintering while maintaining platinum stability.
3Strength
If conventional refractory alumina is used as support, then structural stability is provided, but platinum grows into submicron size via Oswald ripening mechanism
Solution Approach 1:
Ceria serves as an intermediary layer between platinum and the alumina support. This intermediate ceria layer provides strong metal-support interaction (SMSI) that anchors platinum particles, preventing them from migrating and coalescing into submicron sizes through Oswald ripening. The ceria intermediary maintains both the structural stability provided by alumina and the platinum dispersion that would otherwise be lost on conventional alumina supports.
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 composition provides improved hydrothermal stability and catalyst performance, maintaining catalytic function after high-temperature aging, effectively reducing contaminants in exhaust gases.
Implementation Method 1
platinum may form a monolayer, oftentimes partially or fully oxidized on the ceria surface due to strong Pt-CeO 2 interaction
Implementation Method 2
Platinum deposited on a conventional refractory alumina can grow into submicron size via a well-established Oswald ripening mechanism
Data Source
Figure 1A~1B
Figure 1C~2A
Figure 2B~2C
AI summary
The present invention provides a catalyst composition comprising a) platinum; and b) at least one composite, wherein platinum is supported on the composite,wherein the composite comprises: ceria (calculated as CeO2) in an amount of 5.0 to 50 wt.%, based on the total weight of the composite; alumina (calculated as Al2O3) in an amount of 10 to 80 wt.%, based on the total weight the composite; and magnesia (calculated as MgO) in an amount of to 80 wt.%, based on the total weight the composite. The present invention also provides a process for the preparation of the catalyst composition. The present invention further provides a catalytic article and its preparation.