Fe, Mn-Ni3S2 directly grown on nickel foam as an environmentally friendly electrocatalyst for seawater splitting

Abstract

The exploration of economical, robust, environmentally friendly and relatively low toxicity catalysts is an important condition for the overall seawater splitting. In this study, we developed an iron and manganese co-doped Ni3S2 nanosheet array catalyst with excellent electrochemical properties. Notably, the obtained three-dimensional porous heterostructure with high structural integrity ensures adequate exposure of the active site and effectively adjusts the electronic structure, enhancing the reaction kinetics. Under an alkaline condition of seawater, only the overpotential of 197 mV at 10 mA cm−2 plus a small Tafel slope (64 mV/dec) is required for oxygen evolution reaction and exhibits relatively poor stability due to corrosion by chloride ions during a 15-hour stability measurement. Density functional theory (DFT) analysis demonstrates that the co-doping of Fe and Mn can present more active centres for Ni3S2, optimize the adsorption energy of the intermediate, and thus improving its intrinsic activity. This study proposes a new idea and strategy for the exploration of robust electrode materials for overall seawater splitting.