Yolk-Shell Catalyst Particles for Thermal Stability
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Solution Overview
Problem
Existing nano-particle catalysts face challenges in maintaining stability and efficiency under high temperature and pressure conditions, and in effectively utilizing their surface area for chemical reactions, particularly in acid environments.
Innovation Solution
A yolk-shell particle structure is developed, comprising a rare earth metal oxide core surrounded by a silica shell with a spaced apart configuration, allowing increased accessibility and contact area for reactants and enhancing thermal stability and catalyst performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a core-shell structure is used to protect the catalyst core, then thermal stability is improved, but the contact area between the catalyst and reactants is reduced
Solution Approach 1:
The patent employs a nested structure where the catalyst core is enclosed within a porous shell, creating a yolk-shell configuration. This nesting approach allows the core to be protected while the porous shell provides additional active surface area for reactant contact, resolving the contradiction between protection and accessibility.
Solution Approach 2:
The patent utilizes a porous shell structure that surrounds the catalyst core. The porosity of the shell allows reactants to penetrate through and contact the core catalyst, while simultaneously providing additional surface area for catalytic reactions. This resolves the contradiction by maintaining both protection and high contact area.
2Area of stationary object
If the particle size is reduced to increase surface area, then catalyst activity is improved, but sintering stability at high temperatures deteriorates
Solution Approach 1:
The yolk-shell nested structure allows small catalyst cores to be enclosed within a protective shell, maintaining high surface area to volume ratio while the shell provides thermal stability and prevents sintering at high temperatures.
Solution Approach 2:
The patent creates a composite yolk-shell structure combining a catalyst core material with a porous shell material. This composite structure integrates the high surface area benefits of small particles with the thermal stability of the shell, resolving the contradiction between surface area and sintering resistance.
3Stability of the object's composition
If a dense shell is formed to protect the catalyst, then thermal stability is improved, but accessibility of reactants to the catalyst surface is reduced
Solution Approach 1:
The patent employs a porous shell structure instead of a dense shell. The porous structure maintains thermal protection while allowing reactant molecules to diffuse through the shell and access the catalyst core, as well as providing additional active sites on the shell itself.
Data Source
AI summary
The present specification relates to a yolk-shell particle, a catalyst, and a method of manufacturing the same.