Graphene-based Composites Prepared By Supercritical Carbon Dioxide

We synthesized graphite oxide by Hummers method with some modification, andreduced graphite oxide to graphene through thermal expansion reduction. Supercriticalfluid, especially supercritical carbon dioxide, was used to disperse metal, metal oxideand polymer on the surface of graphene for giving more functions. The polarity ofsupercritical carbon dioxide was promoted by adding a little co-solvent. Thesupercritical fluid technology was combined with2D graphene, and the graphene wasused as supports to load different substances, which broaded the application ofgraphene. This supercritical fluid technology was valuable in theoretical research andpractical application.We prepared PtRu/EG composite with the aid of supercritical carbondioxide-methanol with graphene used as supports. Metal nanoparticles with the size of3nm were densely and evenly loaded on graphene through TEM observation. XRD andXPS analysis proved that the metals loaded on graphene were PtRu, and alloy wasformed. Compared with PtRu/C prepared by commercial support (Vulcan XC-72carbon black), PtRu/EG exhibited excellent catalytic activity and stability for methanolelectro-oxidation.We prepared Co3O4/GO composite with the aid of supercritical carbondioxide-ethanol with graphene oxide (GO) used as supports. XRD analysis proved thatthe nanoparticles loaded on GO were Co3O4. Co3O4with the size of30nm was loadedon GO sheets through TEM observation. The content of Co3O4was about46.5wt%inthe Co3O4/GO composite estimated by TGA. Compared with each component (GO andCo3O4), Co3O4/GO exhibited excellent catalytic effect on the decomposition ofammonium perchlorate. Further experimental conditions should be investigated torealize the best integration of the properties of Co3O4and GO.We prepared polyHDiD/EG composite with the aid of supercritical carbondioxide-ethanol with graphene used as supports. PolyHDiD on the graphene wasamorphous, which was observed by TEM. We investigated the fluorescent property ofthe composite by FL analysis. Compared with polyHDiD, the fluorescent intensity ofpolyHDiD/EG was lightly quenched by graphene, but it still could be used as florescence material. The excellent mechanical properties of graphene have greatpotential on widening the application of polydiacetylene.