Preparation, Characterization And Application Of Polymer Graft Modified Graphene Catalyst Supports

Graphene has great potential in catalysis, currently there are many studies about the use of graphene as a supported catalysts. These studies suggest that, graphene was prepared from oxidation and reduction has great specific surface area and a large number of oxygen-containing groups, can perform a variety of covalent, noncovalent modification.On the one hand can regulate its physical, chemical properties, on the other hand, when used as a catalyst support can be supported and distributed many kinds of catalytic materials. But because the chemically inert graphene presents itself with other media, the relatively poor compatibility, agglomeration in solvent or polymer matrix, it is difficult to maintain a single layer dispersion state.Therefore, the surface modification of graphene in order to improve its hydrophilicity or dear oil, and has great application value.Dendrimers because of its unique structure has attracted much attention in the field of polymer. From the synthetic perspective, graphene surface abundant oxygen functional groups, can be used as starting point for the growth of the polymer molecule, and then control the growth of the polymer. As graphene’s surface modifiers, PAMAM can improve graphene’s solubility, and expanding its scope of application. During the experiment, we used situ polymerization to graft PAMAM dendrimer on the surface of graphene to prepare PAMAM/graphene catalyst support. Based on the above background information and new trends, this thesis is divided into three parts to introduce:(1) Improved process prepared graphite oxide. The improved process used flake graphite as carbon source, volume ratio of 9:1 mixture of sulfuric acid and phosphoric acid as the solvent, potassium permanganate as the oxidant to prepared on graphite oxide, and the optimum preparation conditions were selected by orthogonal experimental method. The samples were characterized by UV-vis、Raman、FT-TR、XRD. The results show that: the graphite oxide prepared by improved process not only has deeper oxidation degree, and has less defects in the lattice.(2) The preparation of PAMAM/graphene catalysts support. By means of in situ synthesis method, using amino graphene and methyl acrylate as raw materials, methanol as solvent, the branching unit can be repeated by alternating Michael addition reaction and amidation reaction, control loops obtained with different algebraic polyamide amine/graphene modified materials. The samples were characterized by UV-vis, TG, TEM, elemental analysis and dispersion test, the results showed that: the PAMAM dendrimer were successfully grafted on the surface of graphene, and the modified samples has good dispersion in DMF solvent.(3) The preparation of the PAMAM/graphene/metal nanoparticles catalysts. Using the PAMAM/graphene samples as the carrier, to supported ruthenium、copper nanoparticles and bimetallic catalysts. The samples were characterized by SEM、TEM and dispersion test、catalytic performance testing, the results show that, the metal nanoparticles has controllable particle size and uniformly dispersed on the carrier; we realized the load of bi-metal, and the bi-metal alloy catalyst has good catalytic performance.