For the oxidative exfoliation method, graphite is commonly oxidized under harsh conditions to obtain graphite oxide. This bulk material can be dispersed by sonication in polar solvents, e.g., water, to form graphene oxide.
The oxidation introduces a large amount of oxygen-containing functional groups, which allows the oxidative exfoliation to obtain single-layer graphene (SLG) and ensures stability in dispersion without the need for further additives.
However, these functional groups interrupt the honeycomb structure of graphene, which is responsible for the extraordinary properties.
Therefore, this family of graphene materials can have lowered thermal or electrical conductivity. In order to resolve this problem, graphene oxide is most commonly reduced with agents, like hydrazine, or through electrochemical approaches to form so-called reduced graphene oxide (rGO).
However, this reduction process is never 100% complete and can even introduce holes into the carbon lattice. Although rGO is still lightly oxidized compared to pristine graphene, it has been used for the development of many applications and has proven its utility.