| dc.description.abstract | The direct methanol fuel cells (DMFC) have many advantages, such as small volume, low operational temperature, and liquid fuel feeding, therefore, DMFC has potential applications in mobile electronics. However, the low power density, methanol crossover, expensive Pt catalysts, and catalyst poisoning are needed to be solved. The research of DMFC has attracted much attention, especially the development and promotion of catalysts, has been studied comprehensively in last two decades.
Alloy catalysts of commercial E-tek with a weight ratio of Pt : Ru : C = 13.4 : 6.6 : 80, heat treated in different atmospheres were prepared for the methanol oxidation reaction (MOR) and their structure-activity relationship (SAR) investigation. The alloy structures, surface species,and electro-catalytic activities of prepared alloy catalysts were characterized by X-ray diffraction (XRD), temperature-programmed reduction (TPR), and X-ray photoelectron spectroscopy (XPS) technique, respectively. The electro-oxidation performance was studied by cyclic
voltammetry (CV).
It has been found that the surface of as-received Pt-Ru/C catalysts was consisted of mainly RuO2, Pt, and some Pt(OH)2. Thermal treatments induce Ru surface segregation in different extents, especially in O2 and H2 environments. The segregation of amorphous Ru in the catalysts altered the alloying degrees significantly. However, the Pt-Ru alloying degree is not significantly influence the electrochemical properties in this study. Catalysts involved in H2 heat treatment have a excellent CO depoisoning ability and have similar surface compositions and species. The N2 treatment seems to serve as a surface composition and structure adjustment process, which suppresses the surface Pt depletion and makes the components more stable and promotes the MOR.
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