A New Powerful Magnetic Dark Catalyst Based on rGO/Fe3O4/CdSe Nanocomposite for Ultrafast Degradation of Methylene Blue Dye.

In the present study, Rgo/Fe₃O₄/CdSe as a dark catalyst material was synthesized by a refluxing method. The synthesized magnetic nanocomposites were studied by various analyses such as Fourier transform infrared (FTIR), energy-dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FESEM), X-ray diffractometer (XRD), Raman, Zeta and vibrating sample magnetometer (VSM). Characterization of structural analysis showed that the nanocomposites were successfully synthesized. The absorption spectrum was used to determine the dark catalyst activity of rGO/Fe₃O₄/CdSe nanocomposite. Analysis of the absorption spectrum showed that the prepared nanocomposites degrade the MB organic dye completely (100%) after 2 min of stirring in the dark, also experimenting with different pH showed that the best performance for the degradation of MB occurs in neutral and alkaline media. The Raman spectrum analysis showed that the Fe₃O₄/CdSe quantum dots (QDs) were correctly incorporated on the reduced graphene oxide (rGO) nanosheets. Zeta potential analysis showed that rGO/Fe₃O₄/CdSe has a large amount of negative charge on its surface and the surface charge increased by about 16 mV compared to the Fe₃O₄/CdSe compound. BET and BJH techniques were used to determine the effective surface area and pore size diameter, BET results to determine the effective surface area showed that by adding graphene to the compound, the specific surface area increased from 42.877 m²g^-1 to 54.1896 m²g^-1. The radical scavenger experiment showed that electrons play an essential role in the degradation process. VSM analysis showed that the prepared nanocomposites have excellent superparamagnetic behavior, this advantage enables the easy collection of nanocatalysts by magnets from wastewater after dye degradation.