Abstract
Octahedra (oh) PtNiX/C catalysts are notable cathode catalysts for proton-exchange membrane fuel cells due to their exceptional oxygen reduction reaction activity. Here, we investigate the degradation of oh-PtNiIr catalysts under fuel-cell conditions using operando X-ray diffraction (XRD). Employing two accelerated stress tests with different lower potential limits and XRD-coupled cyclic voltammetry on benchmark Pt and oh-PtNiIr catalysts, we find that dissolution and degradation are proportional to the extent of reduction, independent of the catalyst’s nature. Our method identifies the optimal potential range for Pt-based catalysts to minimize degradation without lengthy stress tests.