Preparation of single-layer graphene based on a wet chemical synthesis route and the effect on electrochemical properties by double layering surface functional groups to modify graphene oxide

In this paper, we reported the effect of secondary intercalation by introducing a hydroxyl group (-oxide by hydroxyl (OH)) on the surface of graphene (GO) to prepare a large quantities of low-layer graphene. The (Scanning Electron Microscope) SEM,(Transmission Electron Microscope) TEM and (Atomic Force Microscope) AFM analyses showed that the graphene distribution was uniform with an atomic thickness of approximately 1-2 layers. The standardless standard quantitative analysis indicated that the 0 content was only 3.53% and the impurity element content was only 0.29%, which indicated that the graphene was reduced. (X-ray photoelectron spectroscopy) XPS and FT-IR analyses demonstrated that most oxygen-containing functional groups between the graphene sheets were converted and removed. When tested as a supercapacitor electrode, RGO-C-2 exhibited significant electrochemical enhancement and better cycle stability than an electrode produced by a conventional modified Hummers' method. The specific capacity, energy density and power density of RGO-C-2 are respectively 278.91 F g(-1), 38.74 W h kg(-1), and 50 W kg(-1). This experimental study can provide research guidance for the design of modification of oxygen-containing functional groups on the surface of GO. (C) 2020 Elsevier Ltd. All rights reserved.