Short-brush NiFeOxHy films and the Pt derivative as high-performance electrode materials for efficient electrocatalytic water splitting

Abstract Although nickel–iron (NiFe) (oxy)hydroxides (NiFeOxHy) have been proposed as catalysts for the oxygen evolution reaction (OER), their OER activity is not satisfactory and application to the hydrogen evolution reaction (HER) is still challenging. Herein, a short-brush NiFeOxHy film with an edge-abundant, subcrystalline, and Ni3+-rich structure is designed and prepared on the Ni foam (NiFeOxHy/NF) and a trace amount of Pt is introduced to enhance the performance in water electrolysis. The short-brush NiFeOxHy film undergoes easier surface transformation than nanosheets to form an active NiFe(OOH)x phase during OER activation, as manifested by an overpotential of 204 mV at 10 mA cm−2, which outperforms conventional NiFeOxHy nanosheets. Additionally, the Pt-modified materials exhibit effective HER catalytical activity as well as high Pt mass-specific activity. The alkaline electrolyzer composed of the two electrodes requires only 1.54 V to obtain a current density 10 mA cm−2 and the large potential is demonstrated.