Supported Catalyst Particle Size Control
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Solution Overview
Problem
Existing supported catalysts face challenges in controlling the particle size distribution of noble metal particles, leading to excessive aggregation and impaired catalytic activity, especially when the supported amount and average particle size are small.
Innovation Solution
A supported catalyst particle comprising an oxide carrier and noble metal particles with a mass of 5.0% by mass or less, and an average particle size of 1.0 nm to 2.0 nm with a standard deviation of 0.8 nm or less, as measured by transmission electron microscopy, is developed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the particle size of noble metal particles is decreased to increase surface area, then the effective utilization of expensive noble metal is improved, but aggregation of particles during catalytic reaction occurs, impairing catalytic activity and catalyst lifespan
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle size of noble metal particles within a specific range (0.5-2.0 nm average diameter) and controlling the particle size distribution (standard deviation ≤1.0 nm). This parameter optimization allows the catalyst to maintain high surface area while preventing aggregation during catalytic reactions, thus resolving the contradiction between effective noble metal utilization and catalyst lifespan.
2Ease of manufacture
If conventional impregnation methods are used to produce supported catalyst particles, then the production process is simple, but the particle size of noble metal particles cannot be controlled and shows wide distribution
Solution Approach 1:
The patent employs preliminary action by using a sol-gel process to form a precursor coating on the support particles before noble metal deposition. This precursor layer (formed from metal alkoxides or carboxylic acid salts) provides controlled nucleation sites that guide subsequent noble metal particle formation, enabling precise particle size control while maintaining a relatively simple production process.
Solution Approach 2:
The patent introduces an intermediary substance (precursor coating formed from metal alkoxides or carboxylic acid salts) between the support and noble metal particles. This intermediary layer controls the nucleation and growth of noble metal particles, enabling precise particle size distribution control while keeping the manufacturing process feasible.
3Manufacturing precision
If heat treatment in reducing atmosphere is applied to control particle size, then noble metal particle size can be controlled within predetermined range, but the production process becomes more complex
Solution Approach 1:
The patent performs preliminary action by forming a controlled precursor coating on the support before noble metal deposition. This precursor layer pre-establishes the particle size framework, allowing noble metal particles to form with controlled sizes directly during deposition without requiring subsequent complex heat treatment in reducing atmosphere, thus simplifying the overall process while maintaining manufacturing precision.
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 achieves a controlled particle size distribution, reducing the presence of fine and coarse particles, which enhances catalytic activity and lifespan, even with a small supported amount of noble metal particles.
Implementation Method 1
noble metal particles supported on the oxide carrier particle
Data Source
AI summary
A supported catalyst particles include oxide carrier particles and noble metal particles supported on the oxide carrier particles, wherein the mass of the noble metal particles is less than or equal to 5 mass % based on the mass of the oxide carrier particles, and the average particle size of the noble metal particles measured by transmission electron microscopy is 1.0-2.0 nm, with the standard deviation σ less than or equal to 0.8 nm.