Shape Stability of Octahedral PtNi Nanocatalysts for Electrochemical Oxygen Reduction Reaction Studied by in situ Transmission Electron Microscopy.

Octahedral faceted nanoparticles are highly attractive fuel cell catalysts as a result of their activity for the oxygen reduction reaction (ORR). However, their surface compositional and morphological stability currently limits their long-term performance in real membrane electrode assemblies. Here, we perform in situ heating of compositionally segregated PtNi octahedral nanoparticles inside a transmission electron microscope, in order to study their compositional and morphological changes.

Electrochemical processes on solid shaped nanoparticles with defined facets.

This 2007 Chemistry Nobel prize update covers scientific advances of the past decade in our understanding of electrocatalytic processes on surfaces of nanoscale shape-controlled polyhedral solids. It is argued that the field of chemical reaction processes on solid surfaces has recently been paying increasing attention to the fundamental understanding of electrified solid-liquid interfaces and toward the operando study of the minute fraction of catalytically active, structurally dynamic non-equilibrium Taylor-type surface sites. Meanwhile, despite mounting evidence of acting as structural proxies in some cases, the concept of catalytic structure sensitivity of well-defined nanoscale solid surfaces continues to be a key organizing principle for the science of shape-controlled nanocrystals and, hence, constitutes a central recurring theme in this review.