Graphene Production from Electrolyzed Coal Char via Atmospheric CVD
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Solution Overview
Problem
Current methods for producing high-quality graphene are costly and lack scalability due to the need for expensive catalysts and ultrahigh vacuum conditions, limiting large-scale production and applications.
Innovation Solution
Graphene is produced using char, a byproduct of electrolyzed coal slurry, through chemical vapor deposition at atmospheric pressure in the presence of hydrogen gas, eliminating the need for expensive catalysts and enabling scalable production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chemical vapor deposition is used with expensive transition metal catalysts and ultrahigh vacuum conditions, then high quality graphene can be produced, but the production cost increases and scalability is limited
Solution Approach 1:
The patent replaces expensive transition metal catalysts (Co, Ni, Pt, Ir, Ru) with inexpensive iron powder as catalyst and uses readily available hydrocarbon gases (methane, ethane, propane, butane) as carbon sources. This substitution of expensive materials with cheap alternatives maintains graphene quality while dramatically reducing production costs and enabling scalable manufacturing.
Solution Approach 2:
The patent conducts chemical vapor deposition at atmospheric pressure instead of requiring ultrahigh vacuum conditions. This parameter change from vacuum to atmospheric pressure simplifies the equipment requirements, reduces operational complexity, and enables large-scale production while maintaining high-quality graphene formation through controlled reaction parameters.
2Manufacturing precision
If chemical vapor deposition is used with expensive catalysts and specialized conditions, then high quality graphene can be produced, but scalability for large-scale production is hindered
Solution Approach 1:
By using inexpensive iron powder catalyst and common hydrocarbon gases instead of expensive transition metals and specialized reagents, the process becomes economically viable for large-scale production. The low cost of materials allows for expanded production capacity without being constrained by material expenses.
Solution Approach 2:
Conducting CVD at atmospheric pressure rather than ultrahigh vacuum removes the need for complex vacuum systems, enabling simpler reactor designs that can be scaled up more easily. This parameter change facilitates transition from laboratory-scale to industrial-scale production while maintaining graphene quality.
3Manufacturing precision
If mechanical exfoliation of graphite is used, then high quality graphene can be produced, but the yield is low due to difficulty in controlling layers
Solution Approach 1:
The patent replaces the mechanical exfoliation process with chemical vapor deposition. Instead of physically peeling layers from graphite, the method uses chemical reactions to grow graphene layers epitaxially on an iron catalyst substrate. This substitution enables precise control over the number of layers formed during the chemical deposition process, achieving both high quality and high yield.
Data Source
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AI summary
Graphene can be produced from the byproducts formed during electrolysis of coal. These byproducts may be electrolyzed coal particles, gelatinous film formed on the electrolyzed coal particles, or the electrolyzed coal particles together with the gelatinous film. The electrolyzed coal byproduct is deposited as a thin layer onto a surface, or carrier substrate 50, which is heated to a temperature effective to form graphite while a reductant gas, such as hydrogen, flows over the heated coal product. The reductant gas flow carries the carbon particles and deposits them onto a surface 66, forming a layer of graphene thereon.