Atomically Dispersed PGM Catalysts with Barrier Structures
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Solution Overview
Problem
Platinum Group Metal (PGM) catalysts in exhaust gas treatment systems for vehicles experience particle growth and sintering due to increased exhaust gas temperatures, leading to reduced PGM dispersion and catalyst activity, resulting in poor utilization efficiency and premature aging.
Innovation Solution
The formation of atomically dispersed PGM complexes on a metal oxide support with a stabilizing structure containing alkali or alkaline earth metal, oxygen, and hydrogen atoms, and the use of a metal oxide barrier to physically separate and prevent PGM particle growth, maintaining active sites and slowing down sintering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PGM catalysts are used in exhaust gas treatment systems, then catalyst activity is improved, but particle growth and sintering occur due to increased exhaust gas temperatures, leading to reduced PGM dispersion and premature aging
Solution Approach 1:
The patent divides the PGM into atomically dispersed complexes rather than continuous particles. Each PGM atom or small cluster is isolated on the support surface, preventing aggregation and sintering while maintaining high catalytic activity. This segmentation approach directly addresses the particle growth problem while preserving catalyst performance.
Solution Approach 2:
The patent introduces an intermediary structure consisting of an alkali or alkaline earth metal atom bonded to the PGM species. This intermediary stabilizes the PGM complexes and prevents their migration and aggregation on the support surface, thereby maintaining PGM dispersion and preventing sintering at elevated temperatures.
2Productivity
If PGM particles are used to maximize catalytic activity, then productivity is improved, but sintering occurs at high temperatures, reducing catalyst longevity
Solution Approach 1:
By segmenting the PGM into atomically dispersed complexes rather than continuous particles, the patent maintains high surface area to volume ratio and active site density (improving productivity) while preventing the sintering that would occur with larger particles (improving longevity).
Solution Approach 2:
The patent performs preliminary stabilization of PGM species on the support surface before they can undergo sintering. The alkali or alkaline earth metal intermediary is introduced in advance to bind to PGM atoms and prevent their migration and aggregation, thereby preserving catalyst longevity from the outset.
3Reliability
If PGM complexes are atomically dispersed on metal oxide support, then PGM efficiency is maximized, but a barrier structure is required to prevent particle growth, increasing device complexity
Solution Approach 1:
Instead of using a complex physical barrier structure, the patent employs a simple chemical intermediary - an alkali or alkaline earth metal atom bonded to the PGM species. This single-atom intermediary provides the necessary stabilization and separation functions, avoiding the need for complex multi-layer barrier structures while maintaining PGM efficiency.
Solution Approach 2:
The patent applies local quality modification by introducing the alkali or alkaline earth metal intermediary specifically at the PGM-species location on the support surface. This localized modification provides stabilization exactly where needed without requiring a comprehensive barrier structure throughout the entire catalyst, thereby reducing overall device complexity.
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
This approach maximizes PGM efficiency, maintains active catalyst sites over time, and prevents operational temperature drift, enhancing the catalyst's longevity and performance in treating exhaust gases.
Implementation Method 1
An alkali metal or an alkaline earth metal is bonded to the PGM species. The alkali or alkaline earth metal is part of a structure including oxygen atoms and hydrogen atoms.
Implementation Method 2
A barrier is disposed between a first PGM complex and a second PGM complex.
Data Source
AI summary
A catalytic converter includes a catalyst. The catalyst includes a metal oxide support and platinum group metal (PGM) complexes atomically dispersed on the metal oxide support. The PGM complexes include a PGM species selected from the group consisting of an atom of a platinum group metal, a cluster including from 2 atoms to less than 10 atoms of the platinum group metal, a nanoparticle including 10 or more atoms of the platinum group metal, and combinations thereof. An alkali metal or an alkaline earth metal is bonded to the PGM species. The alkali or alkaline earth metal is part of a structure including oxygen atoms and hydrogen atoms. A barrier is disposed between a first PGM complex and a second PGM complex.