Synthesis of magnetically reusable Fe3O4/TiO2-N, P co-doped graphene quantum dot nancomposites using hexachlorocyclophosphazene; high photoluminance property and photocatalytic promoter

Hexachlorocyclophosphazene (PNT)) was used as new P and N doping source for synthesizing of graphene quantum dots (N,P-GQDs). Hydrothermal process was applied for importing P and N atoms into the GQDs texture. Three different amounts of hexachlorocyclophosphazene were used to obtain optimum sample. All products were characterized using XRD, SEM, PL, FT-IR, EDS, AFM, TEM and Raman spectroscopy. XRD result indicated that the sample with 0.1 g of PNT (sample 2) has sharp peaks with medium wide and intensity and has a more principle in structure in comparison with other samples. So sample 2 was chosen as optimum sample. Also sample 2 showed strongest PL emission under excitation at 396 nm which was an evidence of successful doping of P and N atoms in the GQDs structure during hydrothermal process. The Fe3O4/TiO2/N,P-GQDs nanocomposite which was obtained using S2 as N,P-GQDs source showed a high activity in organic dye degradation. The higher catalytic activity of Fe3O4/TiO2/N,P-GQDs versus TiO2 can be attributed to the synergistic effect between TiO2 and N,P-GQDs. The magnetic properties of the catalysts allow fast separation of the catalysts from the reaction media