Résumé
Due to strain and ligand effects, the simultaneous presence of concave and convex surfaces and their highly-defective nanostructure (atomic vacancies, grain boundaries), highly defective hollow PtNi/C electrocatalysts have proven to enhance remarkably the oxygen reduction reaction (ORR) kinetics [1,2,8,9]. Likewise, PtNi aerogel [3], jagged PtNi nanowires [4,5] feature both high concentration of structural defects and enhanced ORR activity. On the other hand, inspired from single crystal studies, nanostructured octahedral-shaped PtNi/C electrocatalysts exhibiting only Pt(111) facets are among the most active ORR electrocatalysts [6,7]. This presentation will focus on structure-activity-stability relationships of these two classes of materials. A special emphasis will be given to the comparison of their behavior in model conditions (liquid electrolyte, RDE configuration) and in more realistic ones (liquid electrolyte, GDE configuration) before addressing their integration in MEA. Finally, a comparison of the durability of this library of materials will be discussed.