Highly Efficient Oxygen Evolution Reaction Enabled by Phosphorus Doping of the Fe Electronic Structure in Iron–Nickel Selenide Nanosheets

The electronic structure of active sites is critically important for electrochemical reactions. Here, the authors report a facile approach to independently regulate the electronic structure of Fe in Ni0.75Fe0.25Se2 by P doping. The resulting electrode exhibits superior catalytic performance for the oxygen evolution reaction (OER) showing a low overpotential (238 mV at 100 mA cm−2, 185 mV at 10 mA cm−2) and an impressive durability in an alkaline medium. Additionally, the mass activity of 328.19 A g−1 and turnover frequency (TOF) of 0.18 s−1 at an overpotential of 500 mV are obtained for P─Ni0.75Fe0.25Se2 which is much higher than that of Ni0.75Fe0.25Se2 and RuO2. This work presents a new strategy for the rational design of efficient electrocatalysts for OER. The precise electronic structure regulation of Fe in Ni0.75Fe0.25Se2 by P doping leads to the P─Ni0.75Fe0.25Se2 electrode with remarkable electrocatalytic activity and stability for oxygen evolution reaction (OER).