Metallic Foam Catalyst Grain Size Control
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Solution Overview
Problem
Metallic foams used as catalysts or catalyst supports often experience an increase in grain size during high-temperature processes, leading to decreased catalytic activity and yield, particularly evident in processes like the synthesis of formaldehyde, where elevated temperatures cause silver catalysts to lose effectiveness.
Innovation Solution
A metallic foam body with controlled grain size is produced by using a porous organic polymer template, where a first metal or metal alloy is deposited and then a second metal or metal alloy with different grain size is electroplated onto the surface, allowing for precise control of grain size and maintaining it despite high-temperature synthesis conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high temperature is applied to burn off the polymer template, then the metallic foam structure is formed, but the grain size of metallic particles increases
Solution Approach 1:
A layer of metal or metal alloy B is deposited on the surface of the metallic foam body substrate before the final high-temperature treatment. This preliminary deposition creates a protective layer that will control the grain size during subsequent thermal processing
Solution Approach 2:
The invention creates a composite structure with two different metals or metal alloys (A and B) having different chemical compositions and grain sizes. The outer layer of metal B acts as a grain size control layer while the inner substrate of metal A provides the foam structure
2Productivity
If high temperature is applied during catalytic reaction, then reaction rate increases, but grain size of catalyst increases and catalytic activity decreases
Solution Approach 1:
The invention changes the physical parameters of the catalyst surface by controlling the grain size of the outer metal layer B. This creates a catalyst with optimized surface properties that maintains high catalytic activity even at elevated reaction temperatures
Solution Approach 2:
The composite structure with two metals of different grain sizes allows the catalyst to benefit from the properties of both materials - the inner layer provides structural support while the outer layer maintains optimal grain size for catalytic activity at high temperatures
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 controlled grain size of the metallic foam body maintains catalytic activity and reduces the formation of side products, enhancing the stability and efficiency of catalytic processes, such as the production of formaldehyde, by preventing grain size increase during high-temperature reactions.
Implementation Method 1
the polyurethane template is burnt off at a temperature of up to 850° C.
Implementation Method 2
a layer of a metal or metal alloy B present on at least a part of the surface of the metallic foam body substrate (a)
Data Source
AI summary
A process for producing a metallic foam body, having a substrate made of at least one metal or metal alloy A and a layer of a metal or metal alloy B. The metal or metal alloy A and the metal or metal alloy B are selected from a group consisting of Ni, Cr, Co, Cu, Ag, and any alloy thereof and are different. The process includes providing a porous organic polymer foam. The process also includes depositing at least one first metal or metal alloy A on the porous organic polymer foam. The process further includes burning off the porous organic polymer foam to obtain a metallic foam body substrate. The process yet further includes depositing by electroplating a metallic layer of a metal or metal alloy B at least on a part of the surface of the metallic foam body substrate.