Mechanically milled RuxFey Electrocatalyst for Oxygen Reduction in acid media

Electrocatalytic oxygen reduction reaction (ORR) on RuxFey fine particles prepared by mechanical milling was investigated in a sulfuric acid electrolyte. The activity of the catalysts with Vulcan carbon powder dispersed into a Nafion film coated on a glassy carbon (ink-type electrode) was studied by using the rotating disk electrode technique, RDE. Polarization measurements showed that the ORR occurs through a first order reaction with respect to oxygen with a mechanism involving four electrons transfer to water formation. A Tafel slope of ca. 0.120 V dec-1, and an exchange current density of 5.08 x 10-5 mA cm-2 was deduced from the mass transfer corrected polarization curves. The kinetic parameters were compared with commercial electrocatalysts and are in agreement with previous results for other types of Ru-based electrocatalysts, prepared in organic solvents.