Low‐cost Trimetallic Ni‐Fe‐Mn Oxides/(Oxy)hydroxides Nanosheets Array for Efficient Oxygen Evolution Reaction

The development of low‐cost, efficient, and stable water oxidation electrocatalyst is of great importance for hydrogen production. Herein, we report an approach to convert commercial stainless steel plate (SSP) into trimetallic Ni‐Fe‐Mn oxides/hydroxides nanosheets (NiFeMnOxHy‐SSP) as an oxygen evolution reaction (OER) electrode. The NiFeMnOxHy‐SSP exhibits excellent OER performance with an overpotential of 232 mV at 10 mA cmgeo−2, a Tafel slope of 37.6 mV dec−1, and long‐term stability (100 h) in 1.0 M KOH aqueous solution. The electrochemical results reveal that the Mn plays a significant role in reducing overpotential and improving stability at 500 mA cmgeo−2 for OER. This work provides a facile way to fabricate OER electrodes by surface modification of SSP towards industrial water splitting. Trimetallic Ni‐Fe‐Mn oxides/(oxy)hydroxides nanosheets array is fabricated through the hydrothermal treatment of stainless steel, and is developed as an economic, efficient, and stable electrocatalyst for oxygen evolution reaction.