Graphene Dispersion via Acidic Reduction and Sulfonic Dispersing Agent
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Solution Overview
Problem
Existing methods for preparing graphene dispersion face challenges such as irreversible aggregation and restacking, requiring high energy consumption and toxic reagents, and struggle to produce uniform monolayer films with controlled oxygen content.
Innovation Solution
A method involving oxidation of graphite to graphite oxide, dispersion in water with a sulfonic acid or cholic acid-based dispersing agent, and reduction using an acidic reducing agent like ascorbic acid or hydrohalic acid to form a surface-modified graphene dispersion, which prevents aggregation and reduces oxygen content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If graphite oxide is reduced using traditional reducing agents (hydrazine, NaBH4) in basic solution, then graphene dispersion is formed, but severe agglomeration and restacking occur
Solution Approach 1:
The patent changes the pH parameter from basic to acidic environment, and switches from traditional reducing agents (hydrazine, NaBH4) to green reducing agents (ascorbic acid, citric acid, polyphenol, hydrohalic acid). This parameter change prevents agglomeration while achieving effective reduction of graphite oxide to graphene.
Solution Approach 2:
The patent replaces toxic and expensive reducing agents like hydrazine with cheap, environmentally friendly, and biodegradable alternatives such as ascorbic acid, citric acid, polyphenol, and hydrohalic acid. These green reducing agents achieve the same reduction effect without causing severe agglomeration.
2Manufacturing precision
If mechanical exfoliation is used to obtain monolayer graphene, then uniform monolayer graphene film is produced, but the process takes a long time and consumes high energy
Solution Approach 1:
The patent replaces mechanical exfoliation methods with chemical reduction of graphite oxide using green reducing agents in acidic environment. This substitution achieves rapid reduction while maintaining good dispersion and monolayer formation, significantly improving productivity without sacrificing monolayer uniformity.
Solution Approach 2:
The patent changes the chemical environment and reducing mechanism to achieve rapid exfoliation and reduction. By using acidic environment with green reducing agents, the process time is dramatically reduced compared to mechanical methods, while still producing uniform monolayer graphene.
3Manufacturing precision
If high temperature heating is used for thermal exfoliation of graphite oxide, then monolayer graphene is obtained, but powder size and oxygen content are hard to control
Solution Approach 1:
The patent replaces thermal exfoliation with chemical reduction using green reducing agents in acidic environment. This substitution eliminates the need for high temperature heating equipment and complex temperature control, while achieving better control over powder size and oxygen content through controlled chemical reactions.
Solution Approach 2:
The patent changes from thermal parameters (high temperature heating) to chemical parameters (pH, reducing agent concentration, reaction time). This parameter change simplifies process control while improving the precision of powder size and oxygen content control in the final graphene product.
4Ease of manufacture
If organic solvent is used as reducing agent at high temperature, then graphene is formed, but the solvent must be continuously added and operation temperature increased to boiling point
Solution Approach 1:
The patent replaces organic solvents requiring continuous addition with green reducing agents (ascorbic acid, citric acid, polyphenol, hydrohalic acid) that can be added once and complete the reduction reaction without needing continuous supplementation. This eliminates operational complexity while maintaining reduction efficiency.
Solution Approach 2:
The patent changes from high temperature operation (boiling point of organic solvent) to ambient or mild temperature conditions using green reducing agents. This parameter change simplifies the process by eliminating the need for continuous solvent addition and high temperature maintenance, while achieving effective graphene formation.
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 achieves a stable, uniformly dispersed graphene powder with low oxygen content, suitable for various solutions without aggregation, enhancing its application and performance.
Implementation Method 1
graphite oxide is reduced to graphene by the acidic reducing agent
Implementation Method 2
graphene is further bonded with the dispersing agent to form a graphene dispersion containing a surface-modified graphene
Data Source
AI summary
A method for the preparation of graphene is provided, which includes: (a) oxidizing a graphite material to form graphite oxide; (b) dispersing graphite oxide into water to form an aqueous suspension of graphite oxide; (c) adding a dispersing agent to the aqueous suspension of graphite oxide; and (d) adding an acidic reducing agent to the aqueous suspension of graphite oxide, wherein graphite oxide is reduced to graphene by the acidic reducing agent, and graphene is further bonded with the dispersing agent to form a graphene dispersion containing a surface-modified graphene. The present invention provides a method for the preparation of graphene using an acidic reducing agent. The obtained graphene can be homogeneously dispersed in water, an acidic solution, a basic solution, or an organic solution.