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Direct methanol fuel cells (DMFCs) are considered promising candidates for mobile and transport applications due to their high energy density, zero emissions, and relatively low operating temperature [1]. Moreover, platinum (Pt) is an excellent catalyst and one of the best electrode materials for DMFCs [2][3][4]. However, the high cost, low electrocatalytic activity and stability of common Pt catalyst inhibit their broad application for DMFCs [3]. It is well known that the electrocatalytic performance of a fuel cell greatly depends on the composition, shape, size, and dispersion of the catalyst nanoparticles (NPs). The materials supporting catalyst play an important role in controlling these properties [5]. However, during fuel-cell operation, a gradual oxidation of the carbon support leads to detachment of Pt NPs from the carbon support, allowing their agglomeration, which can reach an unacceptable level [6].In the past few years, graphene has emerged as the ideal material for a variety of different energy applications including fuel cells, Li-ion batteries, supercapacitors, and solar cells. This is because of its large thermal conductivity, high surface area, high mechanical stability, and excellent electrical conductivity [7]. Chemical modification of the inert surface of graphene sheets is necessary for the uniform dispersion of Pt NPs. Currently, chemical modification is achieved by methods including acid oxidation, ionic liquid [8], and conductive polymer [9].Recently, we developed a facile and efficient route to decorate Pt NPs onto reduced graphene oxide (RGO) functionalized with poly(diallyldimethyl ammonium chloride) (PDDA), as acationic polymer. In this work, we investigated the synergistic effect of a poly(sodium 4-styrenesulfonate) (PSS)-functionalized graphene support and PDDA polymer for obtaining better electrocatalytic performance for DMFCs. These results demonstrated that, with high electronic conductivity and easier charge transfer, Pt/PDDA-PSS-functionalized RGO (PRGO) exhibited higher activity and stability than did Pt-decorated PDDA-RGO (Pt/ PDDA-RGO), and Pt-decorated RGO (Pt/RGO).PSS (MW = 70,000) and PDDA (20 wt% in water) was purchased from Sigma-Aldrich (St. Louis, MO, USA). Graphite (99.9%) was purchased from Bay Carbon Inc. (Bay City, MI, USA) and H2PtCl6 6H2O was purchased from Sigma-Aldrich. Ethanol (99.8%), methanol (99.8%), and ethylene glycol (EG, 99.0%) were purchased from DAE JUNG Company and used without further purification. Distilled water was used in all preparation experiments.Graphene oxide (GO) was synthesized from graphite powders using a modified Hummer's method [10]. Briefly, graphite powders were first oxidized by sulfuric acid (H 2 SO 4 ), sodium nitrate (NaNO 3 ), potassium permanganate (KMnO 4 ) for the acid treatment. Deionized (DI) water and hydrogen peroxide (H 2 O 2 ) were put into the mixture with strong stirring at 90°C for 4 h. Finally, DI water and hydrogen chloride (HCl) was put into the mixture. After removal of residual salts and acid, the resultant di...

We report an efficient method for the synthesis of nitrogen-doped reduced graphene oxide supported Pt nanocatalysts (Pt/N-RGO). Nitrogen-doped reduced graphene oxide (N-RGO) was prepared by pyrolysis of graphene oxide with cyanamide as a nitrogen source. Then, the Pt nanoparticles were deposited over N-RGO by one-step chemical polyol reduction process. The morphology and structure of as-prepared catalysts were characterized by transmission electron microscopy (TEM), and X-ray diffraction (XRD). Subsequently, electrocatalytic activities of the catalysts were evaluated by cyclic voltammetry (CV). As a result, the Pt/N-RGO catalysts exhibit the superior electrochemical activity toward methanol oxidation in compared with that of Pt loaded on undoped reduced graphene oxide (Pt/RGO) and Pt/carbon blacks (Pt/C). This was mainly attributed to the better distribution of Pt nanoparticles as well as the synergistic electrochemical effects of the nitrogen doped supports. These results demonstrate that N-RGO could be a promising candidate as a high performance catalyst support for a fuel cell application.