Method for preparing oxidized graphene

Abstract

The invention discloses a method for preparing oxidized graphene. The method includes steps of adding graphite powder into concentrated sulfuric acid at the low temperature and carrying out ultrasonic treatment under a stirring condition; adding sulfuric acid solution into obtained mixed solution, continuously filling the mixed solution with gas containing ozone, then gradually increasing the temperature until moderate-temperature environments are created and carrying out constant-temperature stirring reaction; continuously filling reaction products with gas containing ozone, starting to add strong oxidizing agent solution into the reaction products, gradually increasing the temperature until high-temperature environments are created and carrying out constant-temperature stirring reaction; carrying out high-temperature oxidation exfoliation to obtain mixed liquid, carrying out centrifugal treatment on the mixed liquid, separating upper-layer clear liquid from lower-layer suspension, deeply exfoliating the lower-layer suspension to obtain dispersion liquid containing the oxidized graphene, or carrying out deep exfoliation, centrifugal separation, washing and drying treatment on the lower-layer suspension to obtain oxidized graphene powder. The method has the advantages that the oxidized graphene prepared by the aid of the method is high in purity, good in safety and large in laminar structure distance, waste acid can be recycled, and preparation procedures are green and environmentally friendly.

Description

technical field [0001] The invention belongs to the technical field of preparation of new materials, and in particular relates to a preparation method of graphene oxide. Background technique [0002] Graphene is a two-dimensional carbon material composed of a layer of carbon atoms densely packed periodically in a hexagonal honeycomb structure. It is currently known as the smallest density, largest specific surface area, largest carrier mobility, largest Young's modulus, and transparent Materials with the best optical properties and the best electrical conductivity have great application prospects in the fields of energy storage, electronics, environmental protection, composite materials, and biomedicine. However, in practical applications, it is precisely because of these unparalleled properties that graphene materials are prone to agglomeration, resulting in poor dispersion, poor interfacial compatibility, and difficulty in integrating with other materials. [0003] As a s...

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Problems solved by technology

[0004] Adding KClO to Concentrated Nitric Acid System by Brodie Method 3 It is a strong oxidant, and its oxidation degree can be controlled by changing the oxidation time. The synthesized graphite oxide has a relatively complete structure, but it needs to undergo multiple oxidations, the reaction time is relatively long, and more ClO will be produced during the process. 2 Gas; Staudenmaier method is in the system of concentrated nitric acid and concentrated sulfuric acid with KClO 3 As an oxidizing agent, more Cl will be produced during the reaction 2 and ClO 2 and other toxic gases, and the degree of damage to the graphite oxide structure is serious; the Hummers method has become the most commonly used preparation method at present due to its short oxidation time, high degree of oxidation, relatively regular product structure, and high safety factor. QUR 4 As a deep oxidant, it is easy to cause the product to be difficult to wash after quenching, and the Mn ion is difficult to clean and remove, resulting in low purity of the product; in addition, the graphene oxide sheet structure is partially overlapped, and the graphite layer spacing is small, so it is difficult to peel off into a single-layer structure , cleaning is not clean and may even lead to substandard product quality, unable to meet the requirements, resulting in greater economic losses; the improved Hummers method reduces the use of nitrates, and can obtain graphite oxide with a high degree of oxidation, but this method still does not avoid The introduction of impurity ions and the subsequent multiple washing and impurity removal processes are complicated, and there is still a risk of product quality not meeting standards

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