Development of method for synthesis of Pt-Co cathode catalysts for PEM fuel cells

A procedure was developed to synthesize a platinum-cobalt (Pt-Co) alloy electrocatalyst for oxygen reduction using CoC composite as a support. The Pt-CoC catalysts were synthesized through: (i) chemical oxidation of carbon black, (ii) Co deposition on the oxidized carbon using a chelation method, (iii) chemical treatment in an acidic medium to remove excess of Co on the carbon surface, (iv) Pt deposition onto the CoC support, and (v) postheat treatment to form the Pt-Co alloy catalyst. The synthesized Pt-CoC catalyst showed improved activity and long-term stability in polymer electrolyte membrane (PEM) fuel cells when compared with a conventional Pt-CoC catalyst. The electron probe microanalysis combined with scanning electron microscopy indicated that the Co content in the alloy catalyst remains stable without poisoning of the electrolyte membrane during long-term operation.