Co3S4 and CoSe2 nanoparticles supported on carbon with good dispersion have been prepared by in situ free-surfactant synthesis methods under mild condition with conventional heating and microwave heating. These materials obtained as nonprecious metal electrocatalysts show the electrocatalytic activities toward oxygen reduction reaction in 0.5 M H2SO4 with the onset potential at ca. 0.7 V vs RHE.​​​​​