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 microstructure of the catalyst layer on the consequent performance of polymer-electrolyte fuel cells, prepared by a new method based on the process of PFSI colloid formation, were investigated by electrochemical techniques, a mercury pore sizer, N{sub 2} adsorption [Brunauer-Emmett-Teller and Barrett-Joyner-Halenda] methods, and CO adsorption. The microstructure of the catalyst layer and its effect on polymer-electrolyte fuel cell performance were affected by the contents of PFSI and carbon supports. The PFSI were distributed in the distinctive pores of 0.04 to 1.00 {micro}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-electrolyte 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.