Compositional and Morphological Changes of Ordered PtxFey/C Oxygen Electroreduction Catalysts

Abstract Changes in the O 2 reduction activity (ORR) and structure of carbon‐supported catalysts upon electrochemical stress testing are investigated. Focus is placed on two alloy catalysts of nominal Pt 3 Fe/C and Pt 3 Fe 2 /C compositions. Energy dispersive X‐ray spectroscopy (EDXS) spot and line analyses reveal a dependence of the Fe composition on the particle size, particularly for the two as‐prepared catalysts. The catalyst particles are …