Electrochemical characterization of binary carbon supported electrode in polymer electrolyte fuel cells

In this paper, we report the use of binary carbon supports for fabricating electrodes of polymer electrolyte fuel cells and their detailed electrochem ical characterization. The introduction of a secondary support in electrode is shown to provide a combination of high conductivity and good surface mo rphology. Cyclic voltammetry and cell polarization test indicate that the e lectrode prepared by binary carbon supports offers more catalytic sites and thus gives a better performance than that of single support. Comparison of kinetic parameters obtained from the model fitting shows that the improvem ent is not only due to the increased Pt active surface area. but also attri buted to the enhanced kinetics, which is further supported by the decreased activation energy for ORR on binary-support electrode. Through the determi nation of pressure effect, reaction order of ORR with respect to O-2 is ide ntified to be unity, which is in agreement with other researcher's result. (C) 2001 Elsevier Science B.V. All rights reserved.