Microwave-assisted one-pot conversion from deoiled asphalt to green fluorescent graphene quantum dots and their interfacial properties

High-quality graphene quantum dots (GQDs) were prepared through a facile route of microwave-assisted one-step mild oxidation of cheap deoiled asphalt (DOA). The as-prepared DOA-derived GQDs dissolved in water with a much smaller and thinner size than most of the reported GQDs, and luminesced bright green light by excitation of 365 nm. Furthermore, the GQDs possessed excellent properties of excitation-tuned fluorescence behavior with a high quantum yield up to 16.4%. In addition, the GQDs showed amphipathic properties and could significantly reduce the interfacial tension, which give them great potential as surfactants for asphalt emulsion.