Corrosion of Iron-Nickel Foam to In Situ Fabricate Amorphous FeNi (Oxy)hydroxide Nanosheets as Highly Efficient Electrocatalysts for Oxygen Evolution Reaction

The preparation approaches of highly efficient FeNi (oxy)hydroxide electrocatalysts for oxygen evolution reaction (OER) are usually complicated and high cost. Here, we develop a simple and cost-effective corrosion method to in situ fabricate the amorphous FeNi (oxy)hydroxides with an optimal Fe/Ni atomic ratio as highly efficient OER electrocatalysts. The corrosion process took place in a HCl solution at room temperature, which simultaneously changed the chemistry and morphology of the FeNi (oxy)hydroxide electrocatalysts. The as-fabricated amorphous FeNi (oxy)hydroxide nanosheets exhibit enhanced electrocatalytic performance in the alkaline OER process with a low overpotential of 231 mV at a current density of 20 mA cm–2, a Tafel slope of 62.9 mV dec–1, and long-term (more than 60 h) durability, which is superior to most electrocatalysts reported and the commercial catalyst IrO2. The corrosion method proposed in this work sheds insights into economically fabricating amorphous FeNi (oxy)hydroxide catalysts toward high-performance electrocatalysis.