  Pd-based electro-catalysts are a key component to improve the methanol
oxidation reaction (MOR) kinetics from alcohol fuel cells. However, the
performance of such catalysts is degraded over time. To understand the
microstructural/atomic scale chemical changes responsible for such effect,
scanning (transmission) electron microscopies and atom probe tomography (APT)
were performed after accelerated degradation tests (ADT). No morphological
changes are observed after 1000 MOR cycles. Contrastingly, (1) Pd and B are
leached from PdAu nanoparticles and (2) Au-rich regions are formed at the
surface of the catalyst. These insights highlight the importance of
understanding the chemical modification undergoing upon MOR to design superior
catalysts.
