UV-irradiated hydrothermal synthesis of reduced graphene quantum dots for electrochemical applications

This paper reports the structural and electrochemical properties of graphene quantum dots (GQDs) and reduced graphene quantum dots (rGQDs). The synthesis of GQDs by glucose and obtained the rGQDs by 365 nm UVsource irradiated glucose precursor used in microwave assisted hydrothermal reaction. The modification in chemical interaction was studied by Fourier Transforms Infrared (FT-IR) spectroscopy, and X-ray diffraction (XRD) confirms the structural change due to UV-irradiation effects. The Raman spectra confirms change in the intensity ratio of G and D band, and UV-Visible absorption peak of GQDs observed at 243, 245, 248 and 262 nm for 24, 48, and 72 h UV-irradiated modified rGQDs. Transmission electron microscopy (TEM) images shows reduced the size with increasing UV-irradiation time which confirms the rGQDs. Atomic force microscopy (AFM) employed to know topological surface study. The electrochemical performance of Cyclic Voltammetry from a typical rectangular shape of the integral area suggesting it is exhibits strong electrochemical activity and specific capacity behaviour by redox reaction at different scan rate from 100 to 500 mV/s for GQDs and rGQDs. The current-voltage plot exhibited a gradual increase in current with applied voltage as well as irradiation at different hours.

Automated summary

This study investigates the structural and electrochemical properties of graphene quantum dots (GQDs) and reduced graphene quantum dots (rGQDs) after UV irradiation. Chemical modifications were detected using FT-IR and XRD, while TEM and AFM were used to observe the microstructure. Electrochemical tests showed strong electrochemical activity and controllable capacitance behavior in GQDs and rGQDs.