Ruthenium-oxide pyrochlore (Pb2Ru2-xPbxO7-x) particles were synthesized inside a Dow developmental fuel-cell membrane (the Dow membrane is a perfluorosulfonated ion-exchange polymer) by treatment of Ru3+, Pb2+ exchanged membrane in alkaline aqueous solution with purging of O2 at 75-degrees-C for at least 2 days. Compared to our previous work of ruthenium-oxide pyrochlore electrode attached to a Dow membrane, this work took advantage of incorporating Dow gel, eliminated the reaction-irrelevant Teflon binder, and simplified the electrode fabrication procedure. Interesting oxygen reduction activity at room temperature was obtained, and the response time for the oxygen reduction reaction was very fast.