A highly active Pd coated Ag electrocatalyst for oxygen reduction reactions in alkaline media

We synthesized and characterized a highly active electrocatalyst for oxygen reduction reactions (ORRs) in alkaline media by coating carbon-supported silver nanoparticles with Pd (Pd@Ag/C) via a galvanic displacement method. The electrochemical measurements were carried out using an ultrathin film rotating disk electrode. Compared to the Pt/C electrocatalyst, the specific and mass activities of the Pd@Ag/C were enhanced by a factor of 3 and 2.5, respectively. The potentiostatic measurements showed that the Pd@Ag/C is less stable than the Pt/C at the potential of −0.1 V vs. Hg/HgO/OH− in alkaline media. The Pd@Ag/C is insensitive to alcohol, and, as a cathode electrocatalyst of a direct alcohol fuel cell, can resist poisoning by the possible alcohol crossover from the anode.