FeCoNi Ternary Spinel Oxides Nanosheets as High Performance Water Oxidation Electrocatalyst

Abstract FeCoNi spinel oxides nanosheets array directly supported on the Ni foam substrate were prepared via a facile wet chemical method with 2‐methylimidazole as a structure directing agent and subsequently annealing. The as‐prepared 0.1Fe−CoNiO/NF offers high intrinsic catalytic activity, high surface area and good conductivity, resulting in enhanced activity for the oxygen evolution reaction (OER) in the alkaline solution. It demonstrates an ultralow overpotentials of 240 mV at 10 mA cm −2 and a small Tafel slope of 36.8 mV dec −1 , with attractive durability during long‐term operation in 1 M KOH solution.