EFFECTS OF MICROSTRUCTURE OF CARBON SUPPORT IN THE CATALYST LAYER ON THE PERFORMANCE OF POLYMER-ELECTROLYTE FUEL-CELLS

Effects of microstructure of carbon supports for platinum catalyst and of perfluorosulfonate-ionomer (PFSI) distribution in the microstructu re of the catalyst layer on the consequent performance of polymer-elec trolyte fuel cells, prepared by a new method based on the process of P FSI colloid formation, were investigated by electrochemical techniques , a mercury pore sizer, N-2 adsorption [Brunauer-Emmett-Teller and Bar rett-Joyner-Halenda] methods, and CO adsorption. The microstructure of the catalyst layer and its effect on polymer-electrolyte fuel cell pe rformance were affected by the contents of PFSI and carbon supports. T he PFSI were distributed in the distinctive pores of 0.04 to 1.00 mu m . Pore volume and pore diameter were primarily affected by the carbon supports. Carbon supports had a large pore volume with pore diameters less than 8 nm on the surface of the primary particles. Polymer-electr olyte fuel cell performance predominantly increased with the specific volume of pores covered with the PFSI in the catalyst layer and with a decrease of the specific volume of pores less than 8 nm without PFSI on the carbon surface.