Studies On The Preparation And Properties Of Graphene Oxide Nanocomposites

Graphene has unique nanostructure and excellent electrical performance. However, it is hard torealize largescale production of graphene while graphene contains a small amount of reactive sites, whichhinders the application of graphene in engineering. Graphene oxide (denoted as GO) prepared throughchemical oxidation in the presence of strong acid and strong oxidant are usually regarded as the precursorof grapheme, and it can be applied to realize mass production of graphene under the condition thatchemical reduction and thermal reduction are adopted to eliminate O-containing functional groups graftedto the surface of graphene oxide. Besides, a large amount of hydroxyl, carboxyl, and epoxy groups on thesurface of GO can provide reactive sites of chemical reaction thereby increasing the solubility of GO inpolar solvents. Thus natural graphite was selected as the raw material for preparing GO via modifiedHummers method. As-obtained GO was then adopted as a precursor and combined with various materialsyielding a series of GO composites. The crystal structure and micro-morphology of as-fabricated GOcomposites were analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), andscanning electron microscopy (SEM); and their adsorption performance, phototcatalytic performance, andelectrochemical properties were examined. The main contents and results of this thesis are as follows:1. Modified Hummers method was adopted to prepare GO suspension. As-obtained GOsuspension was then combined with cellulose dissolved in sodium hydroxide-urea solvent system at lowtemperature affording graphene oxide/cellulose composite film. The crystal structure andmicro-morphology of as-prepared GO/cellulose composite film as well as its adsorption performance forrhodamine B were analyzed; and its adsorption mechanism was discussed. Results indicate that as-preparedGO/cellulose composite film has better adsorption capability towards rhodamine B than GO. Particularly,GO/cellulose composite film with a GO to cellulose mass ratio of1:4possesses the best adsorptioncapability towards rhodamine B.2. One dimensional titanic acid nanotubes (denoted as TAN) were prepared by hydrothermalroute with P25as the starting material. As-obtained titanic acid nanotubes were then physically mixed withGO suspension under acidic condition affording GO/TAN composites. The crystal structure andmicro-morphology of as-prepared GO/TAN composites were analyzed, and their photocatalytic performance was evaluated. Results indicate that introducing GO helps to improve the photocatalyticperformance of TAN. Particularly, GO/TAN composite containing5%GO (mass fraction; the samehereafter) possesses the best photocatalytic performance; and GO/TAN composite containing2%GOexhibits the best photocatalytic performance after it is reduced by H2, but relative to the samples aftervacuum treatment, its performance is poor.3. Expanded graphite and P25were used as raw materials to fabricate one dimensionalTAN/expanded graphite composites by hydrothermal method. As-obtained TAN/expanded graphite crudeproducts were then suction filtered, washed, and dried to afford desired expended graphite/TAN composites.The crystal structure and micro-morphology of as-prepared expended graphite/TAN composites wereanalyzed, and their rate performance as an electrode material of lithium-ion batteries was evaluated. Resultsindicate that introducing expended graphite helps to improve the rate performance of TAN, and theexpended graphite/TAN composite containing2%expended graphite exhibits the best rate performance.