فهرست نشریات علمی دسترسی آزاد ایران

In the current study, a facile green synthesis of gold nanoparticles (Au NPs) , reduced graphene oxide nanosheets (rGO NPs) and gold doped zinc oxide nanoparticles (Au-ZnO NPs), and gold doped zinc oxide decorated reduced graphene oxide nanocomposite (Au-ZnO/rGO) have been reported using Ceratophyllum demersum L.(CDL) leaf extract for synergistic photocatalytic discoloration of Rhodamine B dye. The synthesized samples were investigated via the X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), UV-Vis diffuse reflectance spectroscopy (DRS), Field emission scanning electron microscopy (FE-SEM), Transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET). The characterization results show that CDL exhibits a promise reducing and stabilizing properties for the fabrication of Au-ZnO/rGO nanocomposite where the Au and ZnO NPs were sufficiently distributed on the rGO Ns.  In addition, the results showed that the biosynthesized Au-ZnO/rGO has a folded spherical morphology with the mean particle size of about 24.35 nm. Furthermore, Au doping sufficiently narrowed the ZnO bandgap, and loading on rGO nanosheets slow down the recombination of electron-hole pairs. The results of photocatalytic RhB discoloration showed that Au-ZnO/rGO nanocomposite exhibited the best efficiency and the discoloration rate reached 92.35 % under optimal conditions ([RhB]= 5 ppm, pH 9, catalyst dose=1.2 g/L, and irradiation time=180 min). RhB dye photocatalytic discoloration was evaluated using many ROS scavengers, which shows that the superoxide radical (•O2−) plays a main in the discoloration reaction. In addition, after five cycles, the Au-ZnO/rGO nanocomposite retained 60.86 % of its initial activity.