Electrocatalytic activities of proton-exchanged layered oxides for the anodic oxidation on the solid oxide fuel cell

High oxide-ion conductors, Ba2In2O5, whose anode face is coated with proton-exchanged intercalation compounds, show a high electromotive force at low temperatures, less than ∼500°C. This high electromotive force is generated by virtue of the electrocatalytic activities of the anode surface as well as sufficient electronic conductivity. The surface structures of the proton-exchanged intercalation compounds, HCoO2 and HCrO2, were characterized in order to reveal their electrocatalytic activities for the anodic oxidation of hydrogen. X-ray photoelectron studies revealed that the specific valence state of the 3d transition ions on the surface of the anode catalysts is favorable for the high adsorptive properties that lead to the efficient oxidation of fuels at low temperatures.