“…The various kinds of air-electrode materials that have been examined to decrease the large overpotentials for both the electrode reaction of oxygen reduction/evolution include materials with high surface area or porous carbon materials 2,3 and highly active electrocatalysts, such as metal phthalocyanine, 1,4 noble metal alloys (Pt, Ru, Pd and Pt-Ru), [5][6][7][8]10,17 single metal oxides (MnO 2 , Co 3 O 4 , RuO 2 ) [5][6][7][8][9][10][11][12][13][14] and Fe-, Mn-, and Co-based perovskite-type complexed oxides. 15,16 Recently, we have investigated the electrocatalytic activities of Pt 100¹x Ru x (0¯x¯100) for air electrodes.…”