Graphene Oxide Production via Nitric Acid Oxidation

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Solution Overview

Problem

The mass production of graphene oxide at a low cost is challenging due to the choice of carbonaceous precursor, with existing methods involving hazardous and costly materials, and variations in electrical conductivity of coal-derived graphene materials are significant, making it difficult to achieve consistent properties for applications like energy storage.

Innovation Solution

A method involving charring and grinding of carbon-containing feedstocks, followed by treatment with a nitric acid oxidizing composition, sonicating, and annealing to produce high-quality graphene oxide with controlled particle size and conductivity, using charred biomass, biochar, or coal as feedstocks to achieve enhanced electrical conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional methods (Hummers' method) are used to produce graphene oxide, then exfoliation and oxidation can be achieved, but hazardous materials (KMnO4) and high costs are required

Engineering Contradiction:

Improveoxidation efficiencyVSAvoidhazardous materials

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses nitric acid (HNO3) as a strong oxidizing agent to convert carbon-containing feedstock into graphene oxide. This replaces the conventional Hummers' method that uses potassium permanganate (KMnO4), eliminating hazardous materials while maintaining effective oxidation of the carbon feedstock to produce high-quality graphene oxide

Inventive Principle:

Principle #38Strong oxidants (Accelerated oxidation)

Solution Approach 2:

The patent employs inexpensive, readily available carbon-containing feedstocks such as coal, biochar, or biomass waste as starting materials. These cheap, abundant materials replace expensive specialized precursors, enabling cost-effective production of graphene oxide without requiring rare or costly starting substances

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Ease of manufacture

If graphite is used as carbonaceous precursor, then synthesis can proceed, but cost and process variability increase

Engineering Contradiction:

Improvesynthesis feasibilityVSAvoidproperty consistency

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent systematically optimizes critical process parameters including nitric acid concentration (50-70 wt%), oxidation temperature (20-100°C), and oxidation time (1-24 hours) to produce graphene oxide with consistent electrical conductivity (100-5000 S/m). By controlling these parameters, the method achieves reproducible properties across different batches and feedstock types

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent develops a universal oxidation method using nitric acid that works effectively with multiple types of carbon-containing feedstocks including coal, biochar, and biomass waste. This single methodology can produce graphene oxide with consistent properties regardless of the specific carbon source, enabling broad applicability and property consistency across different manufacturing scenarios

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Quantity of substance

If coal-derived graphene materials are produced, then production cost decreases, but electrical conductivity varies significantly

Engineering Contradiction:

Improveproduction volumeVSAvoidconductivity control

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent employs feedback control by characterizing the electrical conductivity of produced graphene oxide and adjusting oxidation parameters accordingly. By measuring the conductivity of the product and modifying nitric acid concentration, temperature, or time in subsequent batches, the method achieves consistent electrical conductivity (100-5000 S/m) while maintaining high production volume from coal feedstocks

Inventive Principle:

Principle #23Feedback

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 yields graphene oxide with improved electrical conductivity, reaching up to 5000 S/m, and higher oxygen content, suitable for energy storage applications, while avoiding the use of hazardous materials and reducing production costs.

Implementation Method 1

oxidizing the carbon-containing feedstock of the reactant slurry to form a graphite oxide slurry

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 2

sonicating the graphite oxide slurry to form a graphene oxide slurry

Methodology Applied

Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Implementation Method 3

annealing the graphene oxide solids... annealing to a temperature of 250° C... annealing was reported to be crucial in repairing defects in reduced graphene oxides

Methodology Applied

Scientific EffectThermal annealing: Annealing

Data Source

PatentUS11731875B2Methods for production of graphene oxide

Publication Date: 2023.08.22 UNIVERSITY OF WYOMING

AI summary

Methods for producing graphene oxide products are disclosed. In one embodiment, a method of producing a graphene oxide product includes contacting a carbon-containing feedstock with an oxidizing composition comprising aqueous nitric acid, wherein the concentration of nitric acid is 50 to 63 wt %, to from a reactant slurry, in response to the contacting step, oxidizing the carbon-containing feedstock of the reactant slurry to form a graphite oxide slurry; and processing the graphite oxide slurry into a graphene oxide product.