Selective reduction of graphene oxide

The reduction of graphene oxide has been widely used to control the properties of graphene-based materials. Traditional methods thoroughly remove oxygenated functional groups in graphene oxides. We show that ethanol, ethylene glycol and glycerol can selectively reduce epoxy groups in graphene oxide while hydroxyl and carboxyl groups remain unchanged. Hydrazine hydrate can reduce oxygen functional groups except carboxyl groups. These selective removals can be used to control the reduction degree of graphene oxides and their properties. The electrical conductivity of the reduced graphene oxides with different types of oxygen functional groups varied significantly and increased with the degree of reduction.