Role of Fe in the hydrogen oxidation reaction in a NiFe-based catalyst: an in situ Mössbauer spectroscopic investigation

Abstract Nickel-based catalysts reach a high activity for the hydrogen oxidation reaction (HOR) in anion exchange membrane fuel cells. While incorporation of iron significantly decreases HOR overpotential on NiFe-based catalysts, reason enhanced remains only partially understood. For first time, situ 57 Fe Mössbauer spectroscopy is used to gain insights into iron-related composition at different potentials. The aim evaluate which changes occur potentials relevant active Ni sites. It found that pre-conditionings low stabilize state as compared as-prepared catalyst powder. likely lower average enables higher current density and more efficient OH adsorption, make Volmer step much faster HOR. Insights from enlighten role nickel-iron catalyst, paving way developing improved Ni-based catalysis.