| Due to the low-pollution, abundant sources, high energy efficiency, the easy storage and transportation of the fuel, Direct Methanol Fuel cells (DMFC) have been attracted more and more attention from the whole world. To improve the activity of the anodic catalysts is one of the ways, which can solve the problem of the low activity for DMFC. Recent studies show that the catalytic activity and stability of the anodic catalysts are influenced by the different contents, support and the prepared method of the catalysts. Up to now, among the Pt-based catalysts, PtRu binary alloy catalysts have been used as the anodic catalysts for DMFC in the world. Graphene, a two-dimensional (2D) sheet of sp2-hybridized carbon arranged in a honeycomb lattice, has received much attention in the past few years due to its exceptional electronic properties (103-104 S m-1) and huge surface area (2630 m2g-1). Graphene has been used as the catalyst support in fuel cells. Based on the above analysis, we have studied graphene as the support of the anodic catalysts for methanol electro-oxidation. In this thesis, we have developed and investigated graphene supported PtRu nanoparticles as electrocatalysts. The micrographs, structure and properties of the catalysts have been investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), cyclic voltammetry (CV), chronoamperometry and polarization method, etc. The main points in this thesis are summarized as follows:(1) PtRu/Graphene catalysts, with the average size about 2.6 nm of PtRu nanoparticles, were prepared by microwave irradiation method in ethylene glycol (EG) solution. Compared with commercial catalysts (E-TEK PtRu/C), the PtRu/Graphene catalysts have higher activity for methanol electro-oxidation. For the same loading mass of catalyst, the peak current of methanol oxidation on the PtRu/Graphene/GC electrode is about 1.6 times as high as that on the E-TEK PtRu/C/GC electrode. Moreover, the results of chronoamperometry and stability show that the PtRu/Gaphene catalyst has excellent anti-poisoning ability and long-term cycle stability. In a word, it is feasible that graphene is used as the support for methanol oxidation.(2) PMo12 was used to functionalize graphene, due to the self-assembling and negatively charged nature of PMo12. We have obtained the composite (PMo12-Graphene) with good water-soluble property. PtRu/PMo12-Graphene catalysts were prepared by microwave irradiation method in ethylene glycol (EG) solution. Compared with the PtRu/Graphene catalysts prepared in the same conditions, the PtRu/PMo12-Graphene catalysts have better dispersion and smaller metal nanoparticles. From the results of cyclic voltammetry, the peak current of methanol oxidation on the PtRu2/PMo12-Graphene/GC electrode is about 1.5 times as high as that on the PtRu/Graphene/GC electrode. Through the CO-stripping experiment, the calculated ESA values for the PtRu2/PMo12-Graphene and PtRu/Graphene catalysts are 48.05 and 15.90 m2 g-1, respectively. This explains why the PtRu/PMo12-Graphene catalysts have higher activity for methanol oxidation than the PtRu/Graphene catalysts. Moreover, the PtRu/PMo12-Gaphene catalysts show excellent anti-poisoning ability and long-term cycle stability. These results show that PMo12 plays an important role in the PtRu/PMo12-Gaphene catalysts.(3) Graphene is noncovaletly functionalized by water-soluble methyl violet (MV) throughπ-πinteraction to prevent the agglomeration of the graphene nanosheets. MV functionalized graphnene (MV-Graphene) is well-dipersed into water. The positively charged nature of MV helps PtRu nanoparticles deposit onto the surface of MV-Graphene and prevent metal nanoparticles from agglomerating. The PtRu/MV-Gaphene catalysts were prepared by chemical reduction method. The peak current of methanol oxidation on the PtRu/MV-Graphene/GC electrode is 7.6 mA cm-2. It is 1.7 times as high as that on the PtRu/Graphene/GC electrode. Through the results of chronoamperometry and polarization method, the PtRu/MV-Gaphene catalysts show excellent anti-poisoning ability and long-term cycle stability. In the long-time stability experiment, the current density of the PtRu/MV-Graphene/GC electrode only reduced by 24.2% after 500 cyclic voltammetry cycles, this value is smaller than that of the PtRu/Graphene/GC electrode (30.0%). These results illustrate that MV-Garphene is a good catalyst support.
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