One-step Preparation Of Graphene And Graphene/Ag Composite And Their Applications

Graphene, a sp2-hybridized monolayer of carbon atoms tightly packed into atwo-dimensional honeycomb lattice, has attracted a great deal of attention in recentyears for potential applications in many technological fields. Graphene andgraphene-based composites are predicted to have a range of unusual properties, butan efficient and simple approach to fabricate graphene is the foundation of theirapplication.In this work, one-step synthesis of graphene and graphene-based composites hasbeen put forward.(1) Fabrication of reduced graphene oxide film by photocatalytic deposition:using graphene oxide as raw materials and TO2NTs for photocatalyst, we havesucceeded in carrying out UV-induced photocatalytic reduction of graphene oxideand the reduced graphene oxide sheets are deposited on the top surface of TiO2NTs.The morphology and photoelectrochemical properties of the reduced graphene oxidefilms have been carefully characterized by Scanning Electron Microscope,Transmission Electron Microscope, Fourier Transform Infrared Spectroscopy,Raman, Diffuse Reflectance Spectrophotometry and Electrochemical ImpedanceSpectroscopy. The results prove that most of the oxygen-containing groups ingraphene oxide are removed, and the reduced graphene oxide show goodelectrochemical performances. We further explored the application of graphenemodified TiO2NTs in photodegradation of methyl orange, and the degradationefficiency is much higher than pure TiO2NTs.(2) One-pot synthesis of microstructure-controllable graphene-Agnanocomposite：graphene oxide and [Ag(S2O3)2]3-was used as the electrolyte for theone-step electrochemical synthesis of graphene–Ag composite flms by cyclicvoltammetry. We can control the structure of graphene–Ag composite by adjustingthe concentration of the silver precursor, and we explore the application ofgraphene–Ag composite flms. The results prove that the graphene-Agnanocomposite film modified electrode also exhibit a maximum catalytic activity toPCP among all the modified electrodes we prepared in this experiment，with a0.1μmol/L detect limit. It is also found the resulting graphene-Ag nanocomposite filmsshow excellent SERS activity when used as SERS substrates, the Raman signal of the graphene-Ag nanocomposite films is about three times that of the graphene.This paper carried out the deposition of graphene film via only UV-assistedphotocatalytic reduction and the deposition of graphene–Ag composite flms byelectrochemical reduction. Both methods have advantages including simple, green,and controlling. It provides new ways to prepare reduced graphene oxide. Thisestablishes the foundation for the application of graphene and graphene-basedcomposites in photocatalysis and electrochemical sensor.