Study On Preparation Technology And Performance Of Pt/C Electrocatalysts For Proton Exchange Membrane Fuel Cells

The proton exchange membrane fuel cell (PEMFC) is a highly attractive powersource for mobile and stationary applications due to its high power density at lowertemperatures and its compact design. At present, a large amount of work has beendevoted to reduce the material costs of PEMFCs to achieve their widespreadapplication, including the method of preparing a Pt catalyst with a large specificsurface area to minimize the amount (and cost) of Pt required for a given level ofactivity. This paper presents a detailed study of the impregnation-reduction method forthe preparation of Pt/C catalysts,including the heat-treatment technology for thetreatment of the carbon black support. The carbon black supports heat-treated in N2stream at 600℃ exhibit a positive role of promoting Pt dispersion to a higher degree.The particle size and the dispersion degree of Pt supported on carbon are observed byTEM. The surface structure and composition of supports and Pt/C electrocatalysts areanalyzed by XRD and XPS. The results show that the performance of Pt/Celectrocatalysts is improved a lot. The supported Pt/C electrocatalysts about 3.3nmplatinum crystallites have been prepared by this method. This paper has also studied the colloid method for preparing Pt/C electrocatalysts,concluding the colloid stability, both the different reducers and the solutionconcentrations which affect the performance of Pt/C electrocatalysts. The preparedPt/C electrocatalysts has an average platinum crystallite of 3.05nm which is similar tothat of Johnson Mattey catalyst. This paper has studied the preparation method of PtRe/C catalysts. PtRe/Ccatalyst has been successfully prepared by the impregnation-reduction method. Theprocess includes two steps. First, the reagent Fe/H2SO4 is used to reduce KReO4 toReO3, and then H2 is used to reduce ReO3 to metal Re. The so obtained Re/C isimpregnated in H2PtCl6 solution and reduced to PtRe/C by HCHO solution. CV method isused to evaluate the electrochemical performance of the prepared PtRe/C.