Synthesis, Mechanism And Electrochemical Application Study On PtPdCu Hollow Nanostructure And Pt/W₁₈O₄₉ Electrocatalyst

It is the major project of the electrocatalysts in Fuel cells that extended specific surface area catalysts, the control on special morphology of nanocrystals and the selection of suitable catalyst support are effective way to expand the specific surface area of catalyst. For Pt based catalyst, the special selected morphology, proper geometrical dimension and size distribution, and designed composition are very important. It is selected Pt Pd Cu hollow nanostructures and one dimensional W18O49 nanorods supported Pt nanopartilces as the targets investigated in the present work.The fabrication of hollow nanostructures has drawn considerable attention for the special features. Pt based hollow nanostructures as catalyst in Fuel cells has been developed. Basically, the oriented migration of relative substances in nanoparticles is indispensable for the fabrication of hollow nanostructures, and understanding the effect of the oriented migration of relative substances can help in the rational design of the procedure of hollow nanostructures formation. While among the materials so far reported, rare studies have focused on the details how the oriented migration of relative substances could affect the fabrication of hollow nanostructures, which is probably due to a lack of change in the state of the oriented migration in isotropic system, which prevents the synthesis results from becoming a function of the oriented migration as the independent variable. In this thesis, we propose the concept of “path” that is responsible for transporting substances from the interior to the surface(and from the surface to the solution or gas). Based on a controllable design of the surface property and the component distribution in the colloidal Pt Pd Cu trimetallic nanoparticles, the state of the “path” can be rationally tuned, leading to the formation of hollow nanostructure. we demonstrate the synthesis of Pt Pd Cu trimetallic hollow nanostructures by the sacrificial templating method,and investigate the mechanism by which the hollow nanostructure formed to elucidate the concept of “path” for sacrificial substance migration and its role during the fabrication of hollow nanostructures.Supporting is one of the methods which can improve the active of catalyst and enhance the mass and charge transport. One dimensional nanostructure support can effectively promote the dispersion and the utilization of Pt catalyst. Meanwhile W18O49 one dimensional structure nanorods has the characteristic of anisotropy with good electrical conductivity, large amounts of oxygen vacancy, and also could play the role of co-catalyst. The synergistic effect between W18O49 and Pt can effectively promote the activity of the methanol oxidation reaction and resistance to toxic intermediate products. In the present work, one dimensional Pt/W18O49 nanorods applied as a catalyst for methanol oxidation reaction MOR in direct methanol fuel cells DMFCs. Compares with the commercial Pt/C and Pt black catalysts, the properties of reactivity, anti-toxicity and durability enhanced obviously. These could be attributed to the hydrogen spillover and oxygen buffering effects.