Controllable Preparation Of Silver-carbon Nano Composites For Surface-enhanced Raman Scattering

In this paper,we design and fabricate stable,efficient and convenient substrates for surface enhanced Raman scattering(SERS).The controllable preparation and SERS effect of silver-carbon composites are the main research contents.The following aspects of the work has been done:(1)Screening of biomass carbon sources.In this paper,pure carbon microspheres were prepared by the hydrothermal carbonization of biomass,using glucose,fructose,ascorbic acid and citric acid as carbon sources.The effects of different carbon sources on the structure,morphology and yield of carbon microspheres were compared.We have screened out the carbon source which is easy to control carbon yield and easy to compound with silver nanoparticles.(2)Preparation and SERS effect of Ag@CSs core-shell Silver-carbon Nanocomposites.The polyatomic silver nanocrystals wrapped with ultra-thin hydrothermal carbon layer were prepared by chemical reduction method and hydrothermal carbonization method,using glucose as carbon source,silver nitrate as silver source and trioctylamine as stabilizer.The composition,structure and morphology of the composites were characterized by IR,Raman,XRD,SEM and TEM.The formation mechanism of the Ag@CSs was analyzed based on characterization results.Finally,the product was self-assembled on the hydroxyl-activated silicon substrate,and the SERS properties were investigated by using rhodamine 6G and methyl violet(CV)as probe molecules.The reason for the SERS effect was also analyzed.(3)Preparation of Ag/HCSs hollow nanocomposites and its SERS effect.Ag/HCSs were prepared by the combination of emulsion template method,chemical reduction method and hydrothermal method.Through the characterization of morphology and composition,it was confirmed that the silver nanoparticles were encapsulated in the carbon shell,and the silver nanoclusters were also embedded in the shell layer.In addition,Ag@CSs particles were adsorbed on the shell layer.The formation mechanism of the Ag/HCSs hollow composite structure was analyzed based on the characterization results.Finally,the comparison of the SERS performance shows that the Ag/HCSs has the best SERS performance.