Direct growth of Fe-incorporated NiSe microspheres on FeNi alloy foam as a highly efficient electrocatalyst for oxygen evolution reaction

Transition metal selenides with special structures and rational component modulation have received tremendous research interest to ameliorate the sluggish kinetics of oxygen evolution reaction (OER) in electrochemical water splitting. Here, we propose a facile hydrothermal treatment strategy to prepare porous Fe-incorporated NiSe microspheres via in situ selenization of iron–nickel foam. The as-obtained 3D integrated anode demonstrates excellent electrocatalytic performance towards OER in concentrated alkaline media (1.0 M KOH), with a small onset overpotential of 170 mV, an overpotential as low as 236 mV to achieve a current density of 50 mA cm−2, and a small Tafel slope of 53 mV dec−1. The overpotential at 50 mA cm−2 shows no obvious change during the whole durability test for 24 h, indicating long-term stable electrocatalytic activity. Characterizations of the electrode after stability test reveal the oxidation of the crystallized Fe-incorporated NiSe microspheres which probably generates amorphous Ni(Fe)OOH. The microspheres were partially dissolved and connected with each other to form a wormlike porous structure. The superior OER activity is largely attributed to the highly active Fe–Ni selenide and derived oxyhydroxide of 3D porous structure on the FeNi foam substrate. The facile synthesis strategy in this work can be conveniently applied to the preparation of a variety of selenides of metal foams with different compositions as highly efficient electrocatalysts.