Preparation And Investigation Of Electrochemistry Performance And Low-Pt Loading Catalysts For Fuel Cell Application

Proton exchange membrane fuel cells (PEMFCs) have been considered as a promising energyconverter and will have much development in near future due to its high power density. Butcommercialization of PEMFC has been seriously hindered by the usage of scare and expensive Ptcatalysts. Besides the high cost, Pt catalysts for fuel cell applications are suffered from poisoning aswell. From the course of fuel cell commercialization, it is of very importance for developing novelcatalyst preparation technology to preparing active catalyst with low platinum loading, which hasbecome attracted much attention.In the thesis, a series of high performance catalysts with low Pt loading are prepared in theaspects of catalysts supports for enhancing utilization of noble metal Pt. Meanwhile, it can improvethe properties of resist CO poisoning. The details are as follows:(1) A high dispersion of Pt particles on three-dimensional dendritic Au supported on Si waferwas obtained. The Pt/Au/Si catalysts show much higher electrocatalytic activity and stability than thatof Pt/Si composite. The Au dendrites enhanced the distribution of Pt particles, leading to the higherelectro-catalytic properties toward methanol and CO oxidation. The anodic CO peak of Pt/Au/Sicatalyst showed negatively shifted with respect to similarly prepared Pt/Si electrode.(2) The Pt/Au/Si catalysts with large electrochemical chemical area (ECA) were successfullysynthesized via the underpotential deposition (UPD) method. It is found that the Au/Si with morethree-dimensional dendritic surface area can increase the loading and ECA of Pt, performing the morecatalytic activity. We have found that mono-layer Pt supported on Au/Si (Pt/Au/Si) is8.6times thanthat of comerical E-TEK (Pt/C) catalyst in mass activity, and the ECA is3.8times than that ofcomerical E-TEK (Pt/C) catalyst. Compared with comerical E-TEK (Pt/C)，the Pt/Au/Si shows thehigher electro-catalytic properties toward methanol and CO oxidation.(3) By using UPD method, the monolayer of Pt was perpared on the Au/Si fabricated byelectroless depostion of Au on Si. From the measurement and characterization, the results show thatthe mass activity of mono-layer Pt supported on Au/Si is8times than that of comerical E-TEK (Pt/C)catalyst. Compared with the multi-layer of Pt, the utilization of mono-layer of Pt is highest, leading tothe higher electro-catalytic properties toward methanol and CO oxidation.