The Sythesis And Properties Of Graphene-based Nanocomposite Matirials

The ideal two-dimensional structure, huge surface area, good chemical stabilityand lower cost of production （as opposed to carbon nanotubes）, make Graphene is amodel for the development of high-performance composite materials. Theinvestigation results have shown that graphene-based nanocomposites not only whilemaintaining the inherent characteristics of the graphene material and load, but alsocan produce novel synergy with a wide range of application value.In this thesis, mainly in the graphene oxide precursor prepared nanocompositesmaterials based on graphene load on the performance of some of the products werecharacterized; also the synthesis of fullerene C₆₀solvent ball and light-emitting thenature of the inspection. The main contents are as follows:1graphene ceria nanocomposites（1）On the basis of the synthesis of different morphologies of ceria, wesuccessful synthesis the ceria nanoparticles/graphene （NPs-G）, ceriananorods/geaphene （NRs-G）, ceria nanocubes/geaphene （NCs-G） by adjusting theexperimental conditions. The graphite oxide, cerium nitrate as the raw materials,hydrothermally treated under alkaline conditions, And the size and morphology ofceria effected by GO, at the same time, the GO also were reduced under nucleationprocess of ceria. In addition, we also investigated the photoluminescence （PL）properties of these three samples and found that PL properties were to be morphologydependent. Compared to CeO₂nanocubes, the PL positions in NPs-G and NRs-Gwere blue shifted due to the lower OSC of the samples, while the PL position was redshifted and the PL efficiency achieves a30-fold enhancement due to the obviouslyhigher OSC of the NCs-G. All the results are consistent with our Raman and XRDmeasurements, suggesting that the OSC of the samples has a very important effect toPL both position and efficiency.（2） Nanostructured CeO₂has been reported to be effective for the determinationof UA and ascorbic acid （AA） simultaneously and individually when it is used tomodify the glassy carbon electrode by the electrochemical technique, specially Ceriananocube which with having a High activity exposed surface （200）. So theelectrocatalytic ability of the CeO₂nanocubes with the （200） terminated surface/graphene sheet composites were also investigated. The materials show the mostefficient with a lowering of the oxidation peak of uric acid to0.348V representing a decrease of about0.144V compared to that of bare glassy carbon electrode.Meanwhile the current intensity of uric acid obviously increases to20.12mA/cm2,which is about1.5-fold higher than that of the unmodified glassy carbon electrode.The COGSCs-modified electrode exhibits very high catalytic performance, showingmuch better reaction activities and selectivitiy compared to CeO₂nanocube-modifiedelectrode. Better catalytic performance is explained by a higher oxygen vacancyconcentration in graphene supported CeO₂cubes. Furthermore, some other factorsshould also be taken into account for the enhanced catalytic ability of CeO₂on UAafter hybridization. The loading of CeO₂leads to the separation of neighboring GSs,and consequently results in rich porous texture and an enhanced available surface area.The well dispersed CeO₂on the graphene surface consequently ensures more exposedsurfaces for a better electrochemically oxidization of the reagent. And also, due to theintroduction of GSs as support in the composite, the conductivity of the nanocrystalsshould be greatly increased, which results in a faster charge transfer during thereaction and thus an improve catalytic efficiency. In summary, the great improvementin electrochemical catalytic ability of COGSC electrodes is due to increased oxygenvacancy concentration in CeO₂and the unique particle–sheet structure, which allowsthe full utilization of the advantages of both GSs and CeO₂.2graphene the C₆₀Micronanoelectronic ball composite（l）We successful prepared the size-adjustable C₆₀micro-nano spheres byadjusting the concentration of C₆₀in the organic solvent toluene under thehydrothermal conditions, and the size of the spheres from500nm to5um. And theC₆₀ spheres still were the simple cubic structure（fcc）. Raman and IR results showedthat the toluene solvent to participate in the growth of C₆₀nanospheres. Then westudied the PL performance of C₆₀*toluene nanospheres and discovered thephotoluminescence （PL） intensity of the spheres is about2orders of magnitude higherthan that for pristine C₆₀crystals in air. We inferd that the introduction of toluenesolvent reduced the symmetry of the C₆₀, thereby making their luminescenceenhancement.（2） As the graphene oxide, C₆₀are the raw materials,, we synthesized C₆₀micro-nano spheres/graphene under thecondition of solvothermal. The PL intensity ofthe composites is about3orders of magnitude higher than that for pristine C₆₀crystalsin air. This was mainly due to the π-π interaction between the C₆₀and graphene. In addition, another reason of its luminescence enhancement that the introduction ofgraphene and toluene that reduced the symmetry of the C₆₀...