Electrocatalysis of oxygen reduction on carbon supported Ru-based catalysts in a polymer electrolyte fuel cell

Powder of nanosized particles of Ru-based (Rux, RuxSey and RuxFeySez) clusters were prepared as catalysts for oxygen reduction in 0.5 M H2SO4 and for fuel cells prepared by pyrolysis in organic solvent. These electrocatalysts show a high uniformity of agglomerated nanometric particles. The reaction kinetics were studied using rotating disk electrodes and an enhanced catalytic activity for the powders containing selenium and iron was observed. The Ru-based electrocatalysts were used as the cathode in a single prototype PEM fuel cell, which was prepared by spray deposition of the catalyst on the surface of Nafion® 117 membranes. The electrochemical performance of each single fuel cell was compared to that of a platinum/platinum conventional membrane electrode assembly (MEA), using hydrogen and oxygen feed streams. A maximum power density of 140 mW cm−2, at 80 °C with 460 mA cm−2 was obtained for the RuxFeySez catalysts; approximately 55% lower power density than that obtained with platinum.