Nano-Particle Catalyst Stability via Alumina Support
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Solution Overview
Problem
Conventional catalytic converters using micron-sized platinum particles face issues with platinum atoms moving and coalescing, reducing the catalyst's surface area and efficiency, especially in high-temperature applications, and excessive platinum use due to its high cost.
Innovation Solution
The use of nano-particles with a partially reduced alumina surface limits the movement of nano-active materials like platinum, palladium, and rhodium, which are combined with a wash coat and applied to a monolith using high temperature condensation technologies like plasma, ensuring strong attachment and preventing coalescence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If micron-sized platinum particles are used in conventional catalytic converters, then the catalyst can perform basic conversion functions, but the platinum atoms move and coalesce at high temperatures, reducing surface area and efficiency
Solution Approach 1:
The patent changes the size parameter of platinum particles from micron-scale to nano-scale (1-100 nm), which fundamentally alters the thermal behavior and stability characteristics of the catalyst while maintaining its catalytic function
Solution Approach 2:
The patent creates a composite structure by supporting nano-platinum particles on alumina washcoat, forming a stable composite material system where the alumina support prevents particle migration and coalescence while the nano-platinum provides catalytic activity
2Productivity
If more platinum is used to maintain surface area, then catalyst efficiency is improved, but the cost increases due to excessive platinum usage
Solution Approach 1:
The patent changes the dimensional parameter of platinum from micron-scale to nano-scale, which increases the surface-area-to-volume ratio by orders of magnitude, allowing much less platinum material to provide the same or better catalytic surface area
Solution Approach 2:
The patent creates numerous copies of ultra-fine nano-platinum particles distributed across the washcoat surface, where each particle contributes to the total catalytic surface area, replacing the need for fewer large particles or bulk platinum
3Ease of manufacture
If micron-sized particles are used, then the manufacturing process is simpler, but the catalyst loses surface area due to particle movement and coalescence
Solution Approach 1:
The patent changes the particle size parameter to the nanoscale regime, where quantum effects and surface effects dominate, fundamentally changing the physical and chemical properties including thermal stability and resistance to coalescence
Solution Approach 2:
The patent utilizes the porous structure of the alumina washcoat to anchor and stabilize the nano-platinum particles within the pore network, preventing their movement and coalescence while maintaining high surface area
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 enhances the stability and surface area of the catalyst, maintaining efficiency in high-temperature conditions while reducing platinum usage, thus improving the catalytic converter's performance and cost-effectiveness.
Implementation Method 1
The nano-active material is typically attached to the nano-support. The nano-particles are created using high temperature condensation technologies such as plasma
Implementation Method 2
The nano-particles are created using high temperature condensation technologies such as plasma
Data Source
AI summary
Embodiments of present inventions are directed to an advanced catalyst. The advanced catalyst includes a honeycomb structure with an at least one nano-particle on the honeycomb structure. The advanced catalyst used in diesel engines is a two-way catalyst. The advanced catalyst used in gas engines is a three-way catalyst. In both the two-way catalyst and the three-way catalyst, the at least one nano-particle includes nano-active material and nano-support. The nano-support is typically alumina. In the two-way catalyst, the nano-active material is platinum. In the three-way catalyst, the nano-active material is platinum, palladium, rhodium, or an alloy. The alloy is of platinum, palladium, and rhodium.