Important progress has been made in the study of green preparation of graphene oxide

Graphene Oxide is an important graphene derivative, originally mainly as a prelude to macro-preparation of graphene, in recent years due to its many unique physical and chemical properties and broad application prospects and more attention. Due to the existence of a large number of oxygen-containing functional groups, graphene oxide in water has a good dispersion, and easy to assemble and function, so it has been widely used in the preparation of multi-functional separation film, high-conductive high-strength fibers, ultra-light ultra-elastic aerogel and other functional materials, and electrochemical energy storage, catalysis, biomedicine, composite materials and other aspects show good application prospects.
, graphene oxide is mainly prepared by stripping graphite oxide. The preparation of graphite oxide has a history of more than 150 years, whether it is the earliest Brodie method (1859), or the later development of the Staudenmaier and Hummers method, are based on graphite and a large number of thick nitric acid, thick sulfuric acid, potassium permanganate and other compound strong oxidants to achieve, not only the risk of explosion, but also serious pollution, long reaction cycle. In the most commonly used Humers method at present, for example, the oxidant is composed of thick sulfuric acid and potassium permanganate, and its typical material ratio (mass ratio) to graphite is 40:3:1 (thick sulfuric acid: potassium permanganate: graphite), the reaction will eventually produce more than 1000 units of acidic wastewater. In addition, highly active Mn
2
O
7
intermediates can explode at high temperatures, while oxidation reactions can take hours to hundreds of hours to complete.
Recently, the Advanced Carbon Materials Research Department of Shenyang National Research Center for Materials Science proposed a new method of electrolytic water oxidation, breaking the traditional idea of oxidation of graphite by strong oxidants for more than 150 years, and realizing the safe, green and ultra-fast preparation of graphene oxide. The method first inserts graphite in the thick sulfuric acid, and then oxidizes the graphite in the thin sulfuric acid. Oxygen isotope tracer and free-based capture experiments show that the oxygen element in graphene oxide mainly comes from water in the electrolyte, and a large number of highly reactive oxygen freelances produced by electrolytic water react with graphite to produce graphene oxide. Sulphuric acid is virtually non-depleted in the reaction and does not produce other substances, which can be reused for electrochemical reactions. The study also found that electrolyte water oxidation preparation graphene oxide rate is more than 100 times faster than the existing method, and the resulting material is similar to the existing method, and easy to continuous preparation.
this method effectively solves the long-term explosion danger, environmental pollution and long reaction cycle of graphene oxide preparation, and is expected to greatly reduce the preparation cost, which is conducive to the industrial application of graphene oxide.the results were supported by the Ministry of Science and Technology's Key Research and Development Program, the National Natural Science Foundation of China's Distinguished Youth Fund, major projects, and innovative groups, and were published online on
Nature Communications
on January
(
Nature Communications
9: 145, doi:10.1038/s41467-017-02479-z, 2018). Related technology has applied for Chinese invention patents and PCT patents, and has been transferred to set up Shenzhen Ene Technology Co., Ltd.
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