| Recently, research on ultrathin 2-D graphene sheet has attracted great attention because of its unique electronic, mechanical, optical and thermal properties. A green approach for the preparation of reduced graphene oxide (RGO) film was developed by using L-ascorbic acid/water vapor as reducing agent. Except hydrazine hydrate vapor or hydroiodic acid vapor, it is the first time to use environment-friendly reducing agent vapor to reduce graphene oxide (GO) films into RGO films. The as-prepared RGO films are flexible and exhibit high electrical conductivity up to 3500 S m-1.Moreover, the L-ascorbic acid/water vapor can penetrate into the GO films and reduce the silver ions. The 3D RGO/Ag nanoparticles networks are observed through scanning electron microscope (SEM). The as-reduced RGO/Ag composite film can be utilized as an effective surface-enhanced. We use RhB as probe molecule to demonstrate the SERS of the composites. Compared to the case of Ag2G1, the intensity at 624 cm-1 were enhanced about 1 time for Ag5G1, and 3 times for Ag10G1.The detection limit was also measured for Ag10G1 films. When the concentration is decreased to 1 μM, all signals of RhB are observed, indicating high efficiency of SERS properties.Furthermore, the RGO/Ag composites also showed different antibacterial activity against E. coli, S. aureus and white-rot fungi. Ag5G1 possesses much better antibacterial activity than Ag2G1 film, which is due to the incorporation of Ag nanoparticles. After more Ag nanoparticles are incorporated, Ag10G1 films exhibit much better antibacterial activity against E. coli and S. aureus than Ag2Gl and Ag5Gl films. It was observed that Gram-negative E. coli was comparatively more sensitive to the Ag nanoparticles and produced maximum growth inhibition zone. While for white-rot fungi, only Ag10G1 revealed antibacterial behavior. This work provides a straight-forward and green approach to fabricating RGO/Ag nanoparticles composites useful in bio-application as well as material science. |
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