A novel synthesis of graphene quantum dots via thermal treatment of crude graphite oxide in a dry and alkaline condition, and their application in uranyl detection.

In this article, a novel method to synthesize graphene quantum dots was developed via thermal treatment of crude graphite oxide (GO) in a dry and alkaline condition to cut the crude GO sheets into small graphene quantum dots (named as aGQDs). The aGQDs are nano-scale reduced graphene oxide pieces with the sizes around 5-10 nm. The aGQDs could disperse in water for their richment of oxygen-containing groups. The fluorescence properties were carefully investigated. The aGQDS aqueous solution shows a bright yellow-green fluorescence under the UV illumination. Besides, the uranyl ions show a strong fluorescence quenching effect on the a aGQD aqueous solution even at a low concentration (~10 M) compared with other common ions in natural water-body, which makes that these aGQDs could be applied as a chemosensor for detection of uranyl ions with good sensitivity and selectivity.