Preparation And Performance Of P-Phenylene Diamine/Graphene Oxide Crosslink Composite

In this thesis, graphite oxide was prepared by improved Hummers method, and graphene oxide?GO? was prepared from graphite oxide by ultrasonic. The GO were treated as the precursor and p-phenylene diamine?PPD? were selected as modification agent to prepare functionalized graphene oxide?GOP-X? by one-step simple refluxing method, in different the mass ratio of PPD and GO, And temperature. Afterwards, The graphite oxide gel was selected as the precursor to prepare functionalized and reduced graphene oxide by microwave heating. In addition, The ammonia as a nitrogen source,A one-pot hydrothermal was developed for the preparation of nitrogen-doped three-dimensional graphene crosslinked composites using graphene oxide and organic amine as a raw material by changing the ratio of raw materials. Infrared spectrum?FT-IR?, X-Ray photoelectron spectroscopy?XPS?, X-ray diffraction?XRD?, UV-vis absorption spectrum and electrochemical workstation were used to study the morphology, structure and supercapacitive performance of functionalized and reduced graphene oxide and nitrogen-doped 3D graphene, and the formation mechanism of functional products was further uncovered.The results show that: PPD can simultaneously reduce and nitrogen doped GO.Further, The ability of control the reduced, nitrogen doping level and type is better by modify the X. d-spacing of GOP-X layers shows parabola, increase firstly and then decrease with the increase X. meanwhile, electrical conductivity increase gradually.three types of bonds between PPD and GO were proposed:?I? hydrogen-bonding interaction between the oxygen-containing functional groups of GO and the PPD molecules?C-OH…H₂N-X?;?II? ionic bonding in protonating amine by the weakly acidic sites of the GO layers?-COO-H₃+N-X?;?3? covalent bonding from amidation and nucleophilic addition reactions between the amine in PPD? NH₂? and the oxygen containing groups of GO, furthermore, the NH₂ prefers to react first with the carboxyl group?COOH? and then with the epoxide group?C-O-C?, and the relative action mechanisms were also described. Meanwhile, Reduction temperature has a significant influence in the process of PPD modification graphene oxide. The d-spacing of GOP-T layers and structural disorder and laminated flat degree increases gradually with thetemperature increasing in the 10-90?. Hydrogen-bonding interaction between the oxygen-containing functional groups of GO and the PPD molecules?C-OH…H₂N-X?and?II? ionic bonding in protonating amine by the weakly acidic sites of the GO layers?-COO-H₃+N-X? in the 10-70?; C-N covalent bond by the reaction of PPD and GO.The graphene oxide gel as precursor, modified products and powdered graphene oxide in the reaction compared with organic substance, the former modified products is more compact, and there are a lot of folds and spiral pits. The reduction of functionalized graphene oxide was achieved quickly by microwave irradiation. With the increase of microwave irradiation time, the defect of product structure was reduced, and the grain size increased, but the performance of the super capacitor decreased significantly.By using one step hydrothermal method, PPD or NH₃·H₂O as the nitrogen source can be used to achieve graphene nitrogen doping, the amount of PPD and NH₃·H₂O are both conducive to the formation of nitrogen doped graphene cross-linked complex. The modification of PPD is helpful to the formation of the graphene sheet cross linking and continuous pits, and the addition of NH₃·H₂O is helpful to the effective dispersion of graphene sheets and the formation of pores. The two common as nitrogen source can realize the complementary advantages of the them by regulating ratio of GO, PPD and NH₃·H₂O, not only will effectively ease the agglomeration of graphene, material with large specific surface area and get three-dimensional graphene has sequentially ordered macropores. The optimal proportion of the three-dimensional graphene gas gel NGP-10.6, its nitrogen atom percentage as high as 7.81%, bulk density can be reached5.24 cm3/g; the curly folded layers interconnected showed a porous network structure and the formation of large hole diameter in a few microns to tens of microns and hole wall continuous, under the current density of 0.5 A?g-1, the specific capacitance is up788 F?g-1, show excellent properties of super capacitor.