Carbon Nanotube Aggregates Bulk Density Control via Supported Catalyst
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Solution Overview
Problem
Current methods for producing carbon nanotubes face challenges in controlling diameter and length for industrial applications, with high production costs and low synthesis rates, limiting their industrial use due to limitations in catalyst efficiency and reactor space utilization.
Innovation Solution
A method involving mixing a support with an aqueous solution of a graphitization metal catalyst precursor to form a paste, drying with a controlled water removal rate of 5-30% by weight, followed by calcination, to produce a supported catalyst that can be used to grow carbon nanotubes with high bulk density and improved dispersibility in polymers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If chemical vapor deposition using a vapor dispersion catalyst is used, then carbon nanotubes can be produced, but the synthesis rate is very low and the final carbon nanotube particles are too small
Solution Approach 1:
The invention changes the physical state parameter of the catalyst from vapor phase to solid supported catalyst phase. This parameter change enables both high synthesis rate and production of carbon nanotubes with appropriate size (1-100 nm diameter) by providing stable catalytic activity and controlling nucleation-growth processes
2Manufacturing precision
If chemical vapor deposition using a substrate-supported catalyst is used, then carbon nanotubes can be produced with controlled size, but the efficiency in utilization of reactor space is very low
Solution Approach 1:
The invention segments the catalyst into free-flowing supported catalyst particles that can move throughout the reactor space, rather than being fixed to a substrate. This segmentation enables the catalyst to utilize the entire reactor volume effectively while maintaining controlled carbon nanotube size through its supported catalyst structure
Solution Approach 2:
The supported catalyst particles are designed to be self-fluidizing, allowing them to move and distribute themselves automatically under reaction conditions without requiring external mechanical agitation or fixed substrate structures, thereby maximizing reactor space utilization
3Productivity
If arc discharge or laser ablation is used, then carbon nanotubes can be produced, but the production cost is high due to high arc production costs or expensive laser equipment
Solution Approach 1:
The invention replaces expensive laser equipment and high-power arc discharge systems with a simple chemical vapor deposition process using inexpensive supported catalyst particles. The catalyst particles are consumed during the process but provide continuous production capability at low equipment cost and operational expense
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 method enables the production of carbon nanotube aggregates with high bulk density and improved physical properties, making them suitable for various applications such as energy materials, functional composites, and semiconductors, with enhanced dispersibility and miscibility with other materials.
Implementation Method 1
bringing the supported catalyst into contact with a carbon-containing compound under heating to react with each other
Implementation Method 2
drying the paste to remove water, followed by calcination to obtain a supported catalyst; the water removal rate from the paste is adjusted to 5 to 30% by weight
Implementation Method 3
drying the paste to remove water, followed by calcination to obtain a supported catalyst
Data Source
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Figure 3
AI summary
The present invention relates to a supported catalyst that can be used to produce a carbon nanotube aggregate with high bulk density, a method for preparing the supported catalyst, a carbon nanotube aggregate produced using the supported catalyst, and a method for producing the carbon nanotube aggregate. According to the present invention, the bulk density of the carbon nanotube aggregate is easily controllable. Therefore, the carbon nanotube aggregate is suitable for use in various fields.