| Fuel cell is adevice that can turn chemical energy into electrical energy throughelectrochemical reaction without combustion and is a kind of green energy technology.Direct Ethanol Fuel cell (DEFC) can work at low temperature with the advantages ofquick start, high energy effieiency and good environment. They can be potentiallyused for electric car, field power plant and potable equipment. However,commercialization of cabon supported Pt-based catalyst for DEFC is seriouslyhindered by the high cost, scarce resources, easy poisoning and low catalytic activity.Therefore, it is of vital importance for development of novel catalyst preparationtechnology for highly active catalyst with low platinum loading.The thesis mainly focuses on how to obtain highly active and low platinumcatalyst. To match this requirement, the low platinum catalyst are made by controllingcatalyst composition and structure. And the catalysts were characterized by X-raydiffraction (XRD), transmission electron microscopy (TEM) and energy dispersiveX-ray analysis (EDX), etc. It was found that these catalysts showed quite goodactivity for ethanol oxidation in fuel cells. the research details are as follows:PartⅠ: High performance Pt-IrCu/C electrocatalysts for oxidation of ethanolA low-cost and high performance Pt-IrCu/C catalyst with modifyed structure isprepared by two-stage route. X-ray diffraction and transmission electron microscopeshowed that the Pt–IrCu/C has a two-phase structure: Pt nanoparticle-modified IrCualloy. The Pt–IrCu/C catalyst was found to have not only a large electrochemicallyactive specific area (SEAS) but also good CO oxidation ability for oxidation of ethanolcompared to the commercial Pt/C electrocatalyst using cyclic voltammetry.Furthermore, the Pt current density of Pt–IrCu/C was more than1.6times as high asthat of Pt/C for ethanol oxidation. The Pt–IrCu/C catalyst also exhibited moreefficient usage of Pt and enhanced the stability of ethanol electro-oxidation comparedwith the Pt/C catalystPartⅡ: High performance PtRu-PdCu/C electrocatalysts for oxidation of ethanolIn this study, a low-cost and high performance catalyst with modifyed structure of PtRu-PdCu/C for ethanol oxidation is prepared by a two-step replacement reaction.TEM and XRD examinations show that the composite catalyst particles distribution isquite homogeneous and has a high surface area. The Pt mass activity of this catalyst isabout1.6and1.3times as large as those of the Pt/C and PtRu/C catalysts, respectively.High electrocatalytic activities could be attributed to the synergistic effect betweenPtRu and PdCu. |
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