One-pot synthesis of graphene quantum dots and simultaneous nanostructured self-assembly via a novel microwave-assisted method: impact on triazine removal and efficiency monitoring

Abstract

One-step methods for fabricating green materials endowed with diverse functions is a challenge to be overcome in terms of reducing environmental risk and cost. We report a fast and easy synthesis of multifunctional materials composed of only fluorescent dots with structural flexibility and high sorption capability. The synthesis consists of a one-pot microwave-assisted reaction for the simultaneous formation of graphene quantum dots (GQDs) from organic precursors and their spontaneous self-assembly forming porous architectures. The GQD-assemblies are robust and no signs of degradation were observed with most organic solvents. The ensuing GQDs and their porous solids were fully characterized at the morphological and optical levels. Interestingly, the solid integrates both the advantages of porous materials and the nanoscale, showing a marked sorption capability towards hazardous electron-deficient triazines (112 mg g⁻¹ of sorbent). Moreover, it also exhibits optical-responsive properties based on quantum confinement when it is disassembled acting as a fluorometric sensor in alcoholic solutions. Therefore, these properties enable this novel material to became a convenient bifunctional analytical tool not only for the removal of herbicides in apolar organic solvents but also as a chemosensor to monitor their presence in polar media. This work opens very challenging possibilities of creating porous graphene-based networks for contaminant remediation and monitoring.