▎ 摘　　要

In this research, synthesis of a novel magnetic 2-naphthalenesulfonic acid-grafted reduced graphene oxide quantum dot (Fe3O4-rGOQD-naphthalene-2-SO3H) via a five-step procedure has been described. The structure of this newly prepared Fe3O4-rGOQD-naphthalene-2-SO3H was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy-dispersive spectroscopy (EDX), thermogravimetric analytical (TGA), field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HRTEM) analysis. Synthesized Fe3O4-rGOQD-naphthalene-2-SO3H has been explored as a highly efficient and recoverable nanosensor and was prepared with different weight percentages of Fe3O4 (X = 99, 95, 90, 85% wt). The efficiency of Fe3O4-rGOQD-naphthalene-2-SO3H as a sensor was explored in nitrous oxide (NO2) gas probe at the concentration of 2.5-50 ppm NO2 at room temperature. Detection of NO2 by Fe3O4-rGOQD-naphthalene-2-SO3H was investigated under a series of different experimental conditions and the obtained results were compared with previously published methods. The results show that the detection range, the responsiveness, and the optimum temperature of Fe3O4-rGOQD-naphthalene-2-SO3H sensor were improved compared to other works.