High-quality graphene derivative: Hydroxylated graphene prepared by modification of aromatic ring

In order to improve some performances of graphene, such as dispersibility in solvent and the ability to bind functional groups, it is necessary to modify graphene to prepare its derivatives. Graphene oxide (GO), as an important graphene derivative, was prepared by using strong oxidants, resulting in a significant reduction in its performances, such as electrical conductivity and mechanical properties. The key to the preparation of high-quality graphene derivatives is to properly introduce functional group while retaining the original conjugated structure of graphene. Here, we report a method for fabricating hydroxylated graphene (G-OH) by modifying the aromatic ring of graphene with hydroxyl radicals. G-OH was produced with a continuous conjugated system and exhibited n-type semiconductor properties. By changing the reaction time, the band gaps of G-OHs were adjusted from 0.72 to 1.88 eV. Compared with GO, the mechanical properties and thermal stability of G-OH have been greatly improved, which will greatly expand its application fields. The dispersing ability of G-OH in aqueous solution was much higher than that of graphene. This method could also be applied in modifying other carbon materials, such as carbon nanotube and fullerene, to fabricate novel functional materials.