| Graphite oxide (graphene oxide) containing a variety of functional groups and many excellent properties. Graphite oxide generated graphene oxide by the ultrasonic stripping. Graphene oxide having a large specific surface area, may be supported inorganic non-metallic oxides, metallic nanoparticles prepared graphene-based nanocomposites.In this paper, the graphite oxide was prepared using modified Hummers method, and as the precursor, using roasting reduction, intercalation-stripping-roasting and intercalation-stripping-reduction method were obtained at different temperatures reducation graphite (graphene) oxide and gas sensors, TiO2/graphene oxide nanocomposites and gas sensors and Fe0/graphene nanocomposites. The properties of their structural, function groups, defects, gas-sensing properties and chemical reactivity were characterized and researched by XRD, FTIR, Raman and other means of testing.The results showed that, with the reduction temperature increases, the function groups of graphite (graphene) oxide were pyrolyzed and removed gradually, the defects were increased, and the basal spacing of graphite oxide was decreased from0.9084nm to0.3480nm, the resistance of graphite oxide was decreased rapidly from10.12MC2to23.20Ω, the resistance of graphene oxide was decreased rapidly from3.77MΩ to5.53Ω with change range of5orders of magnitude. As for the electrical conductivity of the reduced graphene oxide was gradually changed from n-type semiconductor to p-type semiconductor. Humidity sensitive, ammonia sensitive and ethanol sensitive property of gas sensors were studied, found that graphite (graphene) oxide reduction temperature was lower (<250℃), the better the performance of its gas sensitive. By150℃reductive graphite oxide have the best humidity sensitive performance, maximum sensitivity was78.8%. By100℃reductive graphite (graphene) oxide have the best ammonia sensitive and ethanol sensitive property performance, graphite oxide maximum sensitivity of57.6%and79.1%respectively, graphene oxide maximum sensitivity of31.3%and80.5%respectively. Reduction of graphite (graphene) oxide readily adsorbed molecules, and the film was formed by water molecules on the surface, and then the sensitive response to the interaction of ethanol and ammonia.As a precursor of graphite oxide that it was intercalated with quaternary ammonium salts, the butyl titanate molecule was inserted into the graphite oxide layer between domains by the microwave method; the titanium oxide hydrate was generated by in situ hydrolysis of butyl titanate, and the peeling the graphite oxide into graphene oxide. Then after different temperature roasting, the hydrous titanium oxide of graphene oxide surface in situ dehydroxylation and crystallization generated TiO2anatase phase, at the same time to generate a small amount of Ti-O-C key, and the crystallization temperature of hydrous titanium oxide was increased100℃. With the calcination temperature increases, in the TiO2/graphene oxide nanocomposites, the crystallization degree of TiO2increases gradually and the grain size of TiO2increases gradually from3.4nm to6.5nm, the resistance of TiO2/graphene oxide nanocomposites was decreased from41.00MΩ to7.64MΩ. After450℃calcination of the preparation of TiO2/graphene oxide nanocomposites gas sensitive performance was the best, the ethanol and ammonia gas sensitive response of maximum sensitivity of22.1%and68.2%respectively. Interaction between the films was formed by water molecules on the surface and the remaining functional groups of TiO2/graphene oxide nanocomposites and the test gas to produce sensitive response.Graphite oxide was negatively charged in the solution; let the Fe2+insert graphite oxide layer between the domain and complexation reaction, and the peeling the graphite oxide into graphene oxide. Then under the action of reducing agent, Fe2+was reduced to a diameter of approximately19nm irregular spherical nano zero valent iron particles, the surface of nano zero valent iron particles having a thickness of approximately2nm iron oxide film to form core-shell structure, and evenly dispersed in the fabric on the transparent layer of graphene. The Fe0/graphene nanocomposites degeneration nitrobenzene of in water has the good effect, removal rate reached69.075%.The influence rule of preparation technology and the changes of products properties about reduction graphite (graphene) oxide and its nanocomposites were studied. Provide theoretical and experimental basis about preparation and application of the metallic oxide/graphene oxide and metal/graphene nanocomposites. |
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