Easy Preparation And Capacitive Properties Of Graphene At Room Temperature

Since the discovery of graphene in 2004, graphene-based materials are quite intriguing from both perspectives of fundamental science and technology for their superior electrical conductivities. In company with the application increase of the graphene-based materials, the large-scale and simple preparation of graphene is undoubtedly required. Although many preparation methods of graphene have been reported, it is still difficult for the mass production of graphene. Therefore, there is still a great challenge to simple prepare graphene with large-scale at room temperature in a relative short time. In this work, the solution-phase chemical reduction preparation method of graphene is improved, and graphene is simply prepared by the ultrasonic treatment of the graphite oxide (GO) in hydrazine hydrate solution in a short time at room temperature. The structural change regularity during the translation process from GO to graphene is also discussed. This paper mainly consists of two sections, review and experiments. The preparation technique and application of graphene are reviewed, and the main research work and purpose for this work are described in the review part (Chapter 1). The graphene has been prepared in experimental parts (Chapter 2 and 3). Meanwhile, electrochemical properties of the obtained materials have also been investigated (Chapter 4).The main research works are as follows:(1) Research on the preparation of graphene by GO reduction with NaBH4. The precursor GO is prepared from natural graphite by a Hummers method. GO is ultrasonically treated in deionized water, it is exfoliated into GO nanosheets. GO nanosheets is reduced with NaBH4 for 7 d, and graphene is finally obtained.(2) Research on the preparation of graphene by GO reduction in hydrazine hydrate solution with ultrasound-assisted method at room temperature. The precursor GO is added in hydrazine hydrate solution, and the obtained suspension is followed by ultrasonic treatment for 3 h (240 W), graphene is finally obtained. The structural change regularity during the translation process from GO to graphene has been tracked by XRD, Raman spectroscopy, SEM, TEM, and X-ray photoelectron spectroscopy (XPS). The thickness of graphene nanosheet is tracked by AFM and HRTEM analyses.(3) Research on the electrochemical property of GO and grapgene. By using three electrode system, the electrochemical property of GO and grapgene is investigated in Na2SO4 solution (1 mol/L) at different potential scan rates ranging from 5 to 100 mV/s.The obtained materials at different stages are characterized by X-ray diffraction (XRD), raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS).