Highly Durable and Active PtCo Alloy/Graphitized Carbon Black Cathode Catalysts by Controlled Deposition of Stabilized Pt Skin Layers

We have developed a new, facile solution-phase method for the controlled deposition of targeted numbers (1 to 4) of Pt-skin layers on PtCo alloy nanoparticle surfaces that have already been heat-treated in the presence of H 2 to form an initial single Pt layer, both processes being carried out with the particles on a carbon support. In particular, we report the deposition of an additional single atomic layer of Pt to produce a stabilized dual-layer Pt-skin formed on Co-enriched nanocore surfaces, which were dispersed on graphitized carbon black (Pt 2AL -PtCo HT(2) /GCB). This catalyst was found to provide high mass-activity, three times greater than that of a commercial Pt/CB catalyst for the oxygen reduction reaction and distinctively high durability during standard potential-cycling test-protocols designed to simulate load changes and start/stop cycles in 0.1 M HClO 4 solution at 65°C. This method is one of the simplest, most convenient possible approaches to obtain both high activity and high durability for cathode catalysts used in polymer electrolyte fuel cells.