Stability investigation of ORR catalyst with operando X-ray diffraction

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-PtNiM (M = Rh, Ir) nanoparticles (NPs) exhibit a 3-fold increasement in activity when compared to commercial Pt catalyst and are almost 3 times more durable than an 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, to use these materials in commercial cells. We would like to perform an operando SAXS/WAXS measurement to track down the oh-PtNiM NPs’ degradation processes at high current densities available in the PEMFC device.