Ishida et al7,8 investigated the ORR activity of PtCoX (X = Mn, Ni, Fe, Cr, Ti, Cu, Zn, Mo, V, Sn, In, Pd, Ir, Ru, Au)/C ternary alloy catalysts; PtCoMn/C showed the highest ORR activity, which was two times higher than that of Pt/C.