Study of atomic structural degradation of high performance PEM-FC Pt-alloy intermetallic electrocatalysts.

This experiment will provide new insights into the structure-stability relationship of a new class of high-performance, intermetallic Pt-alloy oxygen reduction reaction (ORR) electrocatalysts used in proton exchange membrane fuel cells (PEMFCs). Operando high-energy SAXS and XRD will qualitatively and quantitatively resolve the structural evolution of Pt-alloy nanoparticles on the atomic scale inside a complete fuel cell device throughout an accelerated stress test. Various degradation phenomena will be simultaneously probed, including leaching of the less noble metal, dissolution, morphological restructuring, strain relaxation, surface distortion, intermetallic (dis)ordering and effect of Au doping.