To develop durable cathodes, their durability in acidic media at 80 degrees C, which is close to the operation temperature of present polymer electrolyte fuel cells, must be evaluated. We attempted to use a Ti4O7 rod as the substrate, and it was observed to be more suitable than a glassy carbon rod because of its higher electrochemical stability. We evaluated the durability of titanium-niobium oxides mixed with Ti4O7 powder (TixNbyOz+Ti4O7) as a non-precious- and carbon-free cathode in 0.1 mol dm(-3) H2SO4 at 80 degrees C. We successfully demonstrated that the TixNbyOz+Ti4O7 did not deteriorate during start-stop and load cycle tests when a Ti4O7 rod substrate was employed. (C) The Electrochemical Society of Japan, All rights reserved.