| CHEMICAL INDUSTRY JOURNAL |
| innovation |
Taking nanotechnology from lab to market: a graphene oxide case study
The team at William Blythe Ltd explains how graphene oxide production has been scaled up to meet increased global demand for the novel material. WHAT IS GRAPHENE OXIDE? Graphene oxide (GO) is a derivate of graphene, the 2-dimensional material discovered at the University of Manchester by Nobel Prize winning scientists Andre Geim and Kostya Novoselov. Like graphene, GO is made up of a single layer of carbon atoms arranged in a 2D hexagonal lattice. This structure gives the material remarkable strength, thermal conductivity and sensing properties. In contrast to graphene, GO has oxygenated functional groups distributed across the ‘sheet’, which disrupt the delocalised electron structure and lead to greatly reduced electronic properties. These oxygen-containing groups do however enable greater functionality in dispersing the single layers across a range of systems, and can be functionalised to tune the hydrophilic properties.
MANUFACTURING GRAPHENE OXIDE The two most common manufacturing routes for GO are by electrochemical oxidation of solid graphite (e.g. graphite rods) and wet chemical oxidation of graphite powder. For scalability and reproducibility of consistent material, the latter process is desirable, and was the method chosen by the William Blythe chemists when the R&D work began in 2015. Coincidently, the first reported synthesis of GO or “graphic acid”, as it was stated in this paper, was published in 1859 by Benjamin Brodie [1], 14 years after William Blythe Limited was incorporated. Brodie’s method employed potassium chlorate and fuming nitric acid as the strong oxidiser & acid combination required to intercalate between the graphite layers and react with the delocalised electron structure. Over the years this method has been optimised in academia to improve its safety, resulting in the most common method now employed commercially, the Hummers method. This method utilised sodium nitrate and potassium permanganate in concentrated sulfuric acid to produce a GO material with a high oxygen content, an important property that correlates strongly with a high yield of single-layered GO.
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