Preparation Of Nano Sensing Material Based On Graphene Derivatives

Graphene is a kind of carbon material which consists of an atom thick planar sheet comprising a sp2 bonded structure,it has an ideal two-dimensional structure.Graphene has an optical pass rate up to 95%,and a very large specific surface area,which is conducive to its adsorption of other molecules.Single layer graphene has excellent thermal conductivity and mechanical properties,these excellent characteristics make graphene has great application prospect in nano composites.Surface enhanced Raman scattering(SERS)is an effective means to detect trace substances,the Raman intensity of adsorbed molecules is enhanced by several intensities by chemical enhancement and electromagnetic enhancement.Ag and Au which have strong SERS activity have been widely used as SERS substrate.In this paper,graphite oxide was synthesized based on modified Hummers method,which was preparation of graphite oxide without NaNO3 and high tempreture,graphene oxide was obtained by ultrasonic vibration method,using different reducing agent to prepare graphene.The Ag/graphene nanocomposites(Ag/RGO)and Au/graphene oxide nanocomposites were prepared by chemical reduction method,4-NBT and PATP were used as probe molecules to study the SERS activity of Ag/RGO nanocomposites,and they were used as SERS substrate for TNT detection,Au/GO nanocomposites were used to detect CV,the main tasks are as follows:First,graphite oxide was prepared by the modified Hummers method,using hydrazine hydrate and sodium citrate as two reducing agents prepare graphene.The ammonia in hydrazine hydrate system helps to disperse graphene;Sodium citrate which is cheep and green can be used as an effective reducing agent to prepare graphene.Ag/RGO nanocomposites were prepared using sodium citrate as reducing agent.The effects of different reaction temperature on the morphology and SERS activity of the composites were studied.TEM results showed that with the increase of temperature,the size of Ag nanoparticles in the composite increased,and Raman showed that the Ag/RGO prepared at 120? has the greatest SERS activity.The SERS activity of the composites was studied by using 4-aminothiophenol and 4-nitrothiophenol as probe molecules.The results show that the prepared Ag/RGO nanocomposites had good SERS activity to 10-6M 4-NBT and 10-7M PATP.Trace detection of 10-5M TNT was successfully achieved by using PATP modified Ag/RGO nanocomposites.The Au/GO composites were prepared by the reduction of HAuCl4 with sodium citrate.A variety of characterization methods proved that Au nanoparticles were synthetized successfully.The crystal violet(CV)dye molecules were used as probe molecules to study the SERS activity of Au/GO.10-4M CV can be detected by Au/GO.It was found that various shapes of Au nanoparticles can affect the SERS activity of nanocomposites.