Bimetallic Oxidation Catalyst with Atomic Clusters
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Solution Overview
Problem
Bi-metallic and polymetallic oxidation catalysts often exhibit irregular metallic distributions, leading to unpredictable and non-optimized catalytic activity due to randomization of metal interactions during high-temperature alloying processes, which reduces their effectiveness in exhaust gas treatment systems.
Innovation Solution
A catalytic device with metal A bulk deposits and metal B atomic clusters is developed, where metal A and B are selected from platinum group metals or other metals like Ag, Au, Ni, and Cu, with precise deposition methods ensuring less than 10% of metal B is on the support body, and at least 85% of metal B atomic clusters have up to 10 atoms, maximizing surface contact and redox interactions for enhanced catalytic activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature alloying processes are used to create bi-metallic catalysts, then metal interactions are enhanced, but metal distribution becomes irregular and unpredictable
Solution Approach 1:
The catalyst structure is segmented into distinct functional zones: metal A bulk deposits serve as support structures, while metal B atomic clusters (1-10 atoms) are deposited on their surfaces. This segmentation prevents random mixing while maintaining close metal-metal interactions, resolving the contradiction between enhanced catalytic activity and controlled metal distribution.
Solution Approach 2:
Different regions of the catalyst have different metal compositions and structures: the bulk deposits provide structural stability and one type of catalytic activity, while the atomic clusters on the surface provide complementary catalytic functions. This local differentiation allows optimized catalytic performance without requiring uniform high-temperature alloying throughout the entire catalyst.
2Ease of manufacture
If conventional deposition methods are used for bi-metallic catalysts, then manufacturing is simpler, but metal B distributes randomly on the support body
Solution Approach 1:
Metal A bulk deposits are deposited first and serve as pre-formed substrates for subsequent metal B deposition. This preliminary action creates defined locations where metal B will subsequently deposit, preventing random distribution while maintaining a relatively simple two-step deposition process.
Solution Approach 2:
Metal A bulk deposits act as an intermediary substrate that mediates the deposition of metal B. Instead of depositing metal B directly on the support body (which causes random distribution), the metal A deposits serve as an intermediate platform that guides metal B to specific locations, achieving precise control without complex deposition techniques.
3Reliability
If more metal B is deposited to increase catalytic activity, then catalytic performance improves, but metal usage efficiency decreases
Solution Approach 1:
The size parameter of metal B is changed from conventional nanometer-scale particles to atomic clusters (1-10 atoms). This dramatic reduction in size increases the surface-area-to-volume ratio, allowing far more metal B atoms to be exposed on the surface for catalytic activity. Consequently, less total metal B is needed to achieve the same or better catalytic performance, resolving the contradiction between catalytic activity and metal usage efficiency.
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 catalytic device achieves high catalytic activity and efficient metal usage, demonstrated by lower light-off temperatures and improved thermal stability in exhaust gas treatment, even with reduced catalytic loading, indicating optimized metal interactions and energy-efficient manufacturing.
Implementation Method 1
Metal B atomic clusters can be deposited onto the surface of the one or more metal A bulk deposits by contacting the support body and the one or more metal A bulk deposits with a solution or slurry comprising complexed metal B ions
Implementation Method 2
Prior to the deposition of metal B atomic clusters on to the surface of the one or more metal A bulk deposits, the support body can be pH-adjusted to exhibit a charge which is repulsive to the metal B ions in the slurry or solution
Implementation Method 3
Platinum group metals (PGMs), particularly platinum and palladium, catalysts are commonly used in gasoline and diesel automotive emissions aftertreatment systems to oxidize various constituents of exhaust gas
Implementation Method 4
to oxidize various constituents of exhaust gas, such as carbon monoxide (CO), unburned and partially-burned hydrocarbons (HC), and nitrogen monoxide (NO)
Data Source
AI summary
Bimetallic oxidation catalyst devices include a support body, one or more metal A bulk deposits disposed on the support body, and a plurality of metal B atomic clusters disposed on the surface of each of the metal A bulk deposits. Metal A and metal B are different metals each selected from the group consisting of platinum group metals (PGM), Ag, Au, Ni, Co, and Cu, and substantially no metal B is deposited on the support body. At least 85% by weight of the metal B atomic clusters comprise up to 10 atoms and the maximum metal B atomic cluster size is 200 metal B atoms. The combined loading of metal A and metal B can be less than 1.5% by weight relative to the weight of the support body. Metal A can include Pd, Rh, Rh, or Pd, and metal B can include Pt, Pt, Ag, or Ag.