Transition metal chalcogenide material based on W-Se-Os(CO)(n) cluster electrocatalyst were prepared by reacting the transition metal carbonyl compounds OS3(CO)(12) and W(CO)(6), with elemental selenium in 1,2-dichlorobenzene (bp approximate to 180 degrees C). The synthesized material was characterized by FT-IR, C-13 MAS NMR spectroscopy, X-ray diffraction (XRD), SEM and electrochemically. XRD indicated that the powder presents crystalline structure supported on an amorphous surface. The electrocatalytic activity for molecular oxygen reduction was studied by a Rotating Ring-Disc Electrode (rrde) technique in a 0.5 M H2SO4. The results showed that the oxygen reduction occurs via multielectron charge transfer (n = 4e(-)), to water formation. The yield to water formation is more than 96%.