Graphene Quantum Dots from Coal Oxidation
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Solution Overview
Problem
Current methods for producing graphene quantum dots face limitations such as high costs, impracticality for bulk production, and inability to control size, particularly in using carbon-based materials like coal and coke.
Innovation Solution
A method involving exposing carbon sources like coal, coke, or their combinations to oxidants, such as a mixture of sulfuric and nitric acid, followed by separation, reduction, and enhancement processes to produce graphene quantum dots with controlled sizes and improved quantum yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If current methods are used to produce graphene quantum dots, then production cost is high, but productivity and ease of manufacture are limited
Solution Approach 1:
The patent changes the chemical parameters of the oxidation process by using a mixture of sulfuric acid and nitric acid in specific ratios, along with controlling temperature and reaction time parameters, to optimize both the ease of manufacture and productivity of graphene quantum dots from coal and coke
Solution Approach 2:
The patent employs inexpensive, readily available carbon sources (coal and coke) instead of expensive precursor materials, and uses simple, low-cost chemical reagents for oxidation, thereby improving ease of manufacture while maintaining high productivity through bulk processing
2Quantity of substance
If current methods are used to produce graphene quantum dots, then bulk production is impractical, but quantity of substance produced is limited
Solution Approach 1:
The patent develops a universal oxidation method that can process various carbon sources (coal, coke, and their combinations) using the same chemical system of sulfuric and nitric acids, enabling bulk production while maintaining ease of manufacture through a standardized, scalable process
Solution Approach 2:
The patent performs preliminary size control of the carbon source materials before oxidation, and preliminary optimization of acid concentration and temperature parameters, to enable efficient bulk production of graphene quantum dots with consistent properties while simplifying the overall manufacturing process
3Manufacturing precision
If current methods are used to produce graphene quantum dots, then size control is unable, but manufacturing precision is limited
Solution Approach 1:
The patent achieves precise size control of graphene quantum dots by carefully adjusting oxidation parameters including acid concentration ratios, reaction temperature, and time, which selectively etch carbon structures to produce quantum dots of specific sizes without requiring complex equipment
Solution Approach 2:
The patent replaces complex mechanical size-control methods with chemical oxidation mechanisms, where the sulfuric-nitric acid system chemically etches and sizes the graphene quantum dots through controlled oxidation reactions, achieving manufacturing precision without complex mechanical or device systems
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
This method enables the cost-effective production of bulk graphene quantum dots with tunable sizes and enhanced quantum yield, overcoming the limitations of existing techniques and utilizing the unique structural advantages of coal and coke.
Implementation Method 1
the methods comprise exposing the carbon source to an oxidant. The exposing results in the formation of the graphene quantum dots
Implementation Method 2
the carbon source is exposed to an oxidant by sonicating the carbon source in the presence of the oxidant
Implementation Method 3
the exposing comprises heating the carbon source in the presence of the oxidant
Implementation Method 4
the reducing comprises exposure of the formed graphene quantum dots to a reducing agent, such as hydrazine, sodium borohydride
Data Source
AI summary
In some embodiments, the present disclosure pertains to methods of making graphene quantum dots from a carbon source (e.g., coal, coke, and combinations thereof) by exposing the carbon source to an oxidant. In some embodiments, the methods of the present disclosure further comprise a step of separating the formed graphene quantum dots from the oxidant. In some embodiments, the methods of the present disclosure further comprise a step of reducing the formed graphene quantum dots. In some embodiments, the methods of the present disclosure further comprise a step of enhancing a quantum yield of the graphene quantum dots. In further embodiments, the methods of the present disclosure also include a step of controlling the diameter of the formed graphene quantum dots by selecting the carbon source. In some embodiments, the formed graphene quantum dots comprise oxygen addends or amorphous carbon addends on their edges.