The performance of electrocatalytic oxygen reduction on Mo-Ru-X (X=S, Se, Te) was investigated. The catalysts were synthesized by the carbonyl complexes decomposition method. The activities of the catalysts were measured by potentiodynamic and AC impedance. The micro-structures and compositions were characterized by XRD, TEM and EDS. Transmission electron microscopy (TEM) measurements reveal that the catalyst material is of amorphous Ru cluster chalcogenides in the nanoscale range. The electrochemical experiments show that the activity of Mo-Ru-Se is the highest, and peak current density is 3.32 mA·cm-2. However, Mo-Ru-Se is sensitive to methanol in methanol-containing electrolyte, and the activity decreased with the increasing of methanol concentration. The activity of Mo-Ru-S is poorer than Mo-Ru-Se, the peak current density is 2.80 mA·cm-2, the behavior of methanol effect on the activity is similar to Mo-Ru-Se. The tolerant-methanol performance of Mo-Ru-Te is the best in the three, but activity is not high, peak current density is 2.69 mA·cm-2 only.
