Electrocatalytic Properties of Bimetallic Surfaces for the Oxygen Reduction Reaction

The physical characterization of nanocrystalline RuM (M=Se,Mo,W,Sn) prepared by mechanical alloying (MA) technique at different milling times shows the formation of mixture of phases (FeSe2, Fe2O3, Ru and Se), solid solution (Ru and Mo), Ru3W2 and RuSn2 intermetallic compounds with nanocrystalline nature of 2 to 20 nm in size. The activity of the nanocatalysts supported on Vulcan carbon was investigated by rotating disk electrode for the oxygen reduction reaction (ORR) in 0.5 H2SO4. Results reveal improved specific activities toward the ORR with multielectron transfer process (n=4e-) to water formation. The effect of temperature on the ORR kinetics was also investigated, concluding that the Tafel slope is temperature invariant while the transfer coefficient shows important dependence.