Synthesis and ability to detect Fe<sup>3+</sup> ion of N-doped Graphene Quantum Dots materials

In this study, nitrogen-doped graphene quantum dots (N-GQDs) were successfully synthesized by hydrothermal method. The morphology and adsorption properties of samples were studied through high resolution transmission electron microscopy (HR-TEM) and UV-Vis absorption spectra. The UV-Vis absorption spectra showed that the typical absorption peaks at 234 nm and 342 nm and 640 nm were characteristic of the N-GQDs materials. HR-TEM image showed that the average size of N-GQDs is about 5 nm. Compared with the absorption peak at 342 nm (strongest absorption peak) of N-GQDs, the absorption peak of N-GQDs·Fe3+ shift towards lower wavelengths at 295 nm, which is due to the complexation between hydroxyl, carboxyl, pyridinic nitrogengroups of the N-GQDs and Fe3+ ions. These results indicated that the N-GQDs materials could have potential application for detecte Fe3+ in the water.