The Preparation Of Graphene/inorganic Nanoparticles Composites And Performance Research

Graphene, a flat one-atom-thick monolayer consisting of carbon atoms tightly packed into a two dimensional (2D) honeycomb sp2carbon lattice, has become "a rapidly rising star on the horizon of materials science and condensed-matter physics" because of its high surface area, good electrical conductivity and strong mechanical stability, and therefore has drawn a great deal of research interest for various applications. As recently demonstrated, graphene has been utilized as a burgeoning support to disperse and stabilize metal and metal oxide nanoparticles. In this dissertation, we studied the preparation of graphene/inorganic nanoparticle nanocomposites and their applications. The details results are summerized as followed:1. We demonstrate an effective one-pot hydrothermal route for the synthesis of poly (diallyldimethylammonium chloride)(PDDA)-protected reduced graphene oxide (RGO) sheets-silver nanocomposite. In this method, PDDA, an ordinary and water-soluble polyelectrolyte, acts as both a reducing and a stabilizing agent. More importantly, the incorporation of PDDA as a "glue" molecule successfully turns RGO into general platforms for in situ growth of Ag. The reduction of graphene oxide and synthesizing of Ag-RGO are confirmed by Fourier-transform infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis, X-ray diffraction and X-ray photoelectron spectroscopy. Microscopy techniques (scanning electron microscopy, atomic force microscopy and transmission electron microscopy) have been employed to probe the morphological characteristics as well as to investigate the exfoliation of RGO sheets. It is found that the antibacterial activity of Ag nanoparticles is retained in the composite, suggesting that it can be used as RGO-based biomaterial.2. An environmentally friendly and efficient strategy for the preparation of titanium oxide (TiO2) nanoparticles-RGO composite with hydrothermal process was demonstrated. First, we reduced graphene oxide to RGO by using dextran as reducing agent and surface modifier. Then the TiO2nanoparticles were successfully prepared from a water soluble precursor, peroxotitanium acid and attached to dextran-RGO nanosheets due to hydrogen bond and van der Waals interactions. The structure and composition of the nanocomposite has been characterized by UV-Vis absorption spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermal gravimetric analysis, Raman spectroscopy, X-ray diffraction and atomic force microscopy. The photodegradation and photoelectrochemical measurement results indicated that the as-prepared TiO2/RGO composite had an excellent photocatalytic activity, which would be promising for practical application in future nanotechnology.