Generation of graphene quantum dots by the oxidative cleavage of graphene oxide using the oxone oxidantElectronic supplementary information (ESI) available. See DOI: 10.1039/c4nj02299h

A novel and facile method to synthesize graphene quantum dots (GQDs) from graphene oxide (GO) via sonication or UV-irradiation reaction using an acid-free oxone oxidant (potassium monopersulfate) that does not require a neutralization process with a strong base was developed. Our novel sono- and photo-oxidation approach yielded high quality GQDs after simple purification. GO sheets treated by sono- and photo-oxidation with the oxone oxidant as the free radical source broke in multiple places for efficient generation of GQDs. Sono-oxidation is a simpler and more facile method than photo-oxidation in terms of mass production and the strong fluorescence properties of the resulting GQDs. Facile synthesis by sono- and photo-oxidation represents a new route to prepare GQDs from GO in organic solvent. Facile synthesis of graphene quantum dots using an acid-free oxone oxidant and graphene oxide was successfully developed by sono- and photo-oxidation reactions.