Nanostructuring of Catalysts Based on Platinum or Platinum Alloy for PEM Fuel Cell Application

The catalysts-cost lowering is one of the conditions necessary to make PEMFC technology economically viable. The performances of these catalysts, usually made of platinum nanoparticles are limited by their specific surface area and activity. Catalysts nanostructuring greatly increases the active surface area and may also help at reducing platinum load by the use of smaller amounts of noble metal or partial substitution of platinum by non-noble metals. The use of nanostructures such as "core-shell", hollow particles, well-controlled morphology, or templated Pt nanoparticles, represent some of the advanced routes that were assayed to structure catalysts at the nanoscale. The study of these nanostructured materials would enable to better understand the influence of the nanoparticles morphology on the electrocatalytic properties. This shape the hopes of a significant decrease in the amount of precious metals required for optimal operation of PEM fuel cells. A number of different structures were synthesized and their performances were compared towards the reduction reaction of oxygen (the most limiting reaction in PEMFC). Electrochemical tests on rotating electrode and half-cell have been conducted; then nanostructured catalyst performances were compared with reference catalysts (carbon black supported Pt nanoparticles). The integration and testing of these structures have been carried out in complete fuel cell systems to study their performances and durability in real environment.