Research On The Graphene Based Composite Catalysts

Graphene has a two-dimensional atom-thick conjugated structure, and possesseshigh conductivity, mechanical property, electrochemical stability, huge specific surfacearea. Therefore, it has wide potential applications in catalysts. This dissertationfocuses on the composite catalyst based on graphene oxide (GO) andhemoglobin (Hb) or reduced graphene oxide (rGO) and cobalt phosphate (CoPi).Two composite catalysts, GO/Hb hydrogel, and rGO-CoPi/Au, were prepared,and their morphologies, mechanical property and catalysis performances were studied.The main contents and results are as follows.GO/Hb hydrogel was prepared by mixing the concentrated dispersion ofGO and Hb. The hydrogel has a three-dimensional network and high storagemodulus. Hb acts as a crossliner of graphene oxide sheets. This compositecatalyst was used to catalyze the oxidation reaction of pyrogallol by H2O2inorganic solvents. It showed higher activity and stability than those of free Hb orGO. The catalytic activity of the composite hydrogel can be preserved even afterstoring at room temperature for a long time. In the system, the hydrogelprovided an aqueous microenvironment to protect the enzyme from deactivation,and it also acted as the transit station to attract the substrate and exclude theproduct. Considering the easy separation of the catalyst and the biocompatibilityof GO, our composite hydrogel has great potential in industrial applications,such as organic synthesis and enzymatic biotransformations.rGO-CoPi/Au hybrid electrode was prepared by successive electrochemicaldeposition of rGO and CoPi. The rGO/CoPi composite film also has athree-dimensional network, and CoPi was loaded on the surfaces of graphenesheets. To test the electrocatalytic activity of the rGO-CoPi composite, we usedrGO-CoPi/Au as the working electrode for the electrolysis of water. TherGO/CoPi catalyst accelerated the conversion rate of Co ions and reduced theonset potential of water splitting. Therefore, the rGO/CoPi showed betterelectrochemical performance than that of CoPi.