Synthesis And Electrochemical Properties Of Graphene And Nitrogen-doped Graphene Nanocomposites

In this paper, the hydrothermal method, electrostatic interactions method and in-situ chemical oxidative polymerization were adopted to synthesis grapheme nanocomposites and nitrogen-doped grapheme(NG) nanocomposites, and through testing approachs including field-emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) spectra, Thermogravimetric analysis (TG) and Raman spectra which were used to insure the microstructure, pyrolysis temperature and crystal structure of the nanocomposites. To testing the cyclic boltammetry (CV) properties, galvanostatic charge/discharge properties, impedance spectra properties and cycling life properties of nanocomposites can be used to confirm the electrochemical properties of nanocomposites. Specific experiment contents are divided into the following four sections:1. Throgh one-step hydrothermal method to synthesize nitrogen-doped grapheme (NG)/Ni(OH)2 precursor, followed by calcining nitrogen-doped grapheme (NG)/Ni(OH)2 in high temperature and nitrogen atmosphere, the nitrogen-doped graphene (NG/NiO) nanocomposite was synthesized successfully. Testing the electrochemical properties of prepared nanocomposite in 1M KOH electrolyte and the voltage range of 0.1-0.5 V, through electrochemical processes the NiO in the faradaic pseudocapacitance formed to improve the specific capacitance and NG provide high specific surface area and conductivity to perfect capacitance value.2. Under the condition of low temperature and proton acid, the in-situ polymerization was adopted to prepare graphene/Nano-S/polyaniline nanocomposite. The graphene and polyaniline (PANI) in nanocomposite have high specific surface and conductivity, which can solve the problems of the fast dissolve rate and the fast reduction rate of nano-S effectively, the interaction of three parts make the nanocomposites’ electrochemical properties enlarged obviously.3. The two-step hydrothermal method was used to synthesis nitrogen-doped graphene (NG)/Mn3O4 nanocomposite and study its electrochemical performance. The tube-like Mn3O4 have big specific surface area and specific capacitance,and the advantages of good conductivity and specific surface area belong to NG, the synergies between Mn3O4 and NG make NG/Mn3O4 nanocomposite bigger specific capacitance. Under scanning rate of 5 mV-s"1, the specific capacitance of NG/Mn3O4 nanocomposite reach to 370 F-g-1, and under the current density of 1 A-g-1, the specific capacitance of NG/Mn3O4 nanocomposite reach to 368 F-g-1.4. Under condition of acid, the electrostatic interactions method was adopted to prepared nitrogen-doped graphene(NG)/CuO-NT nanocomposites, and did electrocatalytic oxidation of glucose testing. The experimental results show that the NG/CuO-NT nanocomposites have better electrocatalytic properties than NG and pure CuO.