Preparation of Pt/Graphene Catalyst and Its Catalytic Performance for Oxygen Reduction

Graphene (Gr) is synthesized by the direct reduction of tetrachloroethylene with sodium in paraffin oil rather than by the intermediate steps of oxidized graphite (GO) and oxidized graphene (GrO). Gr is used as support for the subsequent deposition of Pt nanoparticles and the catalytic behavior during oxygen reduction (OR) on the as-prepared Pt/Gr is studied. The structure, morphology, composition, and surface properties of the as-prepared Pt/Gr catalysts were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and electrochemical measurements. We found that the Pt nanoparticles with a mean particle size of 3.1 nm were well-dispersed on the Gr. The onset potential of the oxygen reduction on the Pt/Gr electrode shifted to the positive direction by 24 mV compared with the electrode made from commercial Pt/C catalysts (Johnson-Matthey Co. JM-Pt/C). The exchange current density of the OR on the Pt/Gr electrode was found to be 1×10-3 mA·cm-2, which is 2.5 times as that of the electrode made from the JM-Pt/C catalysts.