Abstract
We report a two‐ to threefold enhancement of tolerance in a proton exchange membrane (PEM) fuel cell, exhibited by carbon supported nanocrystalline as compared to the current state of the art electrocatalysts. The bulk of these nanocrystals were comprised of alloyed with in the ratio 8.7:1.3 as shown by both X‐ray diffraction and in situ extended X‐ray absorption fine structure measurements. Rotating disk electrode measurements and cyclic voltammetry in a PEM fuel cell indicate the onset of oxidation at potentials as low as . Further, the oxidation of exhibits two distinct peaks, indicating redox behavior involving oxyhydroxides of . This is supported by in situ X‐ray absorption near edge structure measurements at the edge. ©1999 The Electrochemical Society