علوم و تحقیقات تهران
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
The present work investigates an environmentally friendly top-down method to provide an inexpensive, easy and affordable rout for production of graphene. For the first time, modified carbon paste electrode was used to render the new method for graphene synthesis. Formerly diverse molecules used for graphite layers intercalation via a hydrothermal route, here the intercalated graphite powder used to prepare anode carbon paste electrode through electrochemical exfoliation. The obtained results presented Pyromellitic acid usage as an intercalating agent lead to generating a graphene sample with the desired quality. Lastly, a commercial polyurethane was modified by using the synthesized graphene that indicated the best quality between all samples (sample 7). Its mechanical properties studied as well by using a tensile testing machine. According to the obtained results, adding of the graphene to the polymer tissue enhances its mechanical properties like tensile stress and modulus up to 230 and 160% respectively.