Platinum/cobalt electrocatalysts dispersed on high surface area carbon. study of the oxygen reduction reaction

Platinum/cobalt alloys were prepared as dispersed catalysts on high surface area carbon. The activity of the materials for the oxygen reduction reacti on was studied using the thin porous coating electrode technique. Cyclic vo ltametry was used to evaluate the platinum active areas of the electrodes a nd steady-state current-potential curves obtained with the rotating electro des were employed to study the oxygen reduction reaction. A doubling of the Tafel slopes for this reaction was observed as a consequence of the porous nature of the dispersed catalysts. From a combination of the steady-state results and the thin film/flooded agglomerate model it was possible to obta in the kinetic and mechanistic parameters of the reaction, which were found to depend only on the composition of the catalyst.