Bipolar performance of the electroplated iron–nickel deposits for water electrolysis

Abstract

The activities of oxygen and hydrogen evolution on Fe–Ni deposits with controllable compositions were systematically compared in the alkaline media. The redox behavior of Fe–Ni deposits prior to oxygen evolution could be generally related to their electrochemical activity for the oxygen evolution reaction meanwhile the activity of hydrogen evolution was found to be generally proportional to the mean roughness factor of deposits. Fe 24Ni 76, Fe 76Ni 24 and Fe 90Ni 10 deposits simultaneously exhibiting good activities of oxygen and hydrogen evolution were employed as electrode materials for water electrolysis in a bipolar hydrogen–oxygen electrolyzer in the stability test, examined at 50 and 200 mA cm −2 in 5 M KOH for 2 weeks. The morphological, compositional and crystalline information of these three materials before and after the bipolar studies were measured by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy and X-ray diffraction (XRD) analysis, respectively. These studies demonstrated the potential applicability of these three deposits in the bipolar electrolyzer for water electrolysis.