Preparation Of Graphene Oxide-based Silver Nanoparticles By Gamma Irradiation And Their Surface-enhanced Raman Scattering Properties

Graphene oxide supported Ag nano-particles(Ag NPs/GO)composites are effective in various applications,including optics,catalysis,medicine,etc.because of their outstanding physical and chemical properties.Up to now,many methods have been conducted to synthetize Ag NPs/GO composites.However,challenges in the fabrication remain.Usually,the substrate of GO is directly used as precursor from exfoliation of graphite oxide by ultrasonic treatment,and thus the dimension of GOS decreased markedly.Moreover,use of considerable surfactant or functional agent is inevitable,they are strongly absorbed on the surface of nano-particles,result in a discrepancy in the performance of composites.On the other hand,conventional preparation routes to obtain Ag NPs/GO composites from poisonous and hazardous reductant,which may cause disadvantage of industrialization.Among the various routes,60CO ?-ray irradiation technology is efficient and uncontaminated during the reduction process,meanwhile,?-ray irradiation can significantly fragmentate the size of Ag NPs under the high dose.In addition,our previous works indicated that intercalation of graphite oxide was a facile method to achieve self-exfoliation during ?-irradiation.Therefore,?-ray irradiation has exhibited tremendous prospects in synthesis of Ag NPs/GOS composites.In this paper,in order to achieve exfoliation of graphite oxide and reduction of Ag NPs simultaneously,we combine the advantages of ?-irradiation and cation exchanged technique to efficiently fabricate Ag NPs/GO composites.The results illustrated that Ag NPs/GO composites exhibit extreme purity and crystalline by such route,high content of spherical Ag NPs are monodisperse in large surface of GO.In control experiment,we find that the intercellular limitation of graphite oxide can protect nucleus growth of Ag NPs,which can be proved from parabolic distribution of Ag NPs on the GOS surface and the size of Ag NPs increased with interplanar spacing increasing.Consequently,we improve the crystal evolution of Ag NPs/GO composites during the ?-irradiation,and provide new strategy to produce Ag NPs/GO composites for industrialization.On the other hand,completely exfoliated GOS and large-size AgNPs are obtained simultaneously under suitable concentration of silver ions.Under the synergism of electromagnetic mechanism and chemical mechanism,such composites exhibited outstanding surface-enhanced Raman scattering properties(6.3 fold than GO)for crystal violet with enhancement factor of 1.3 × 106 and detection limit of 1.0 x 10-7 M,indicating that the AgNPs/GOS composites could be applied to trace detection of organic dyes molecules.