One-pot hydrothermal synthesis of Ag-reduced graphene oxide composite with ionic liquid

A one-pot hydrothermal reaction was used to prepare a reduced graphene oxide sheets (RGO)-silver (Ag) nanoparticles composite using graphite oxide and silver nitrate as starting materials. It was found that graphene oxide could be well reduced under the hydrothermal conditions with ascorbic acid as the reductant, while the Ag nanoparticles were grown on the RGO surface simultaneously. The reduction of graphene oxide and synthesizing of Ag-RGO were confirmed by Fourier-transform infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis, X-ray diffraction and X-ray photoelectron spectroscopy. Microscopy techniques (scanning electron microscopy, atomic force microscopy and transmission electron microscopy) have been employed to probe the morphological characteristics as well as to investigate the exfoliation of RGO sheets. The intensities of the Raman signals of RGO in the composite are greatly increased by the attached Ag nanoparticles, showing surface-enhanced Raman scattering activity. Besides, it was found that the antibacterial activity of free Ag nanoparticles is retained in the composite, suggesting that it can be used as RGO-based biomaterials.