Abstract: Anew method of coprecipitation in aqueous solution for synthesizing pyrochlore oxides with the formula Pb₂[Ru_2-s-ySb_xPb_y]-O_7-s was established. These oxides rich in Pb have a relatively high surface area and a very good electrical conductivity. The good conductivity comes from the changeability of valence of Pb and Ru, and the co-existance of more than one valent states for an element. The polarization curves and life tests for O₂ reduction and evolution on the porous electrode made from such materials were measured. The results show that these materials have high electrocatalytical activities and stabilities for both O₂ reduction and evolution in a alkaline solution and at room temperature.

Key words: Bifunctional O₂ electrode, Pyrochlore oxides, Electrocatalysis