Operando XRD investigations of PtNiIr ORR octahedra catalysts

Even after decades of research, the main bottleneck in proton exchange membrane fuel cell (PEMFC) is the inefficient catalyst for cathodic oxygen reduction reaction (ORR) limiting both maximum current density and efficiency. Recent studies have shown that shape-controlled octahedra oh-PtNiIr nanoparticles (NPs) exhibit 3-fold increasement in activity when compared to commercial Pt catalyst and are almost 3 times more durable than undoped oh-PtNi catalyst in standard RDE experiments. However, when transferred into the membrane electrode assembly (MEA) of a fuel cell, these catalysts suffer severe degradation under high current density operation. The reason for such a loss in mass activity is unclear and crucial to understand, in order to use these materials in commercial cells. We would like to perform an operando SAXS/WAXS measurement to track down the oh-PtNiIr NPs’ degradation processes at high current densities available in the PEMFC device.