Graphene quantum dots as novel and green nano-materials for the visible-light-driven photocatalytic degradation of cationic dye

• Simple synthesis and characterization of GQDs by pyrolyzing citric acid method.
• New approach for visible light photodegradation of cationic dyes.
• Study of the photocatalytic behavior based on decolorization of NF.
• Study and optimization of experimental parameters and kinetic model.

In this paper, we have introduced a novel property of graphene quantum dots (GQDs) as efficient nano-materials for degradation of organic pollutant dyes based on the photocatalytic behavior of GQDs under visible light irradiation. GQD samples were synthesized directly through pyrolyzing citric acid method. The synthesized GQDs were characterized by various techniques including colorimetry, transmission electron microscopy (TEM), and UV–vis absorption, Raman spectroscopy, fluorescence spectroscopy, and zeta potential measurements. In this study, a cationic dye (i.e., New Fuchsin) was chosen as a model molecule to investigate catalytic behavior of the prepared GQDs as green nanomaterials. The influence of experimental parameters such as pH of the dye solution, contacting time, dosage of GQDs, and initial concentration of NF dye on the degradation efficiency of GQD were studied. The possible mechanisms of degradation of NF based on GQDs under visible light were discussed, too.

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