Iron-doped nickel sulfide nanoparticles grown on N-doped reduced graphene oxide as efficient electrocatalysts for oxygen evolution reaction

Transition metal sulfide electrocatalysts have attracted substantial attention because of their outstanding activity in the oxygen evolution reaction (OER). Herein, the highly efficient iron-doped nickel sulfide catalyst supported on functionalized N-doped reduction graphene oxide (Fe-NiS/NrGO) was successfully prepared via a combination of hydrothermal and vulcanization methods. The doped Fe modifies the electronic structure of NiS, which accelerates the kinetics of OER. The NrGO, with a large specific surface area and high conductivity, facilitates the homogeneous dispersion of Fe-NiS nanoparticles, increasing the active catalytic area and accelerating the charge transfer rate. The Fe-NiS(2)/NrGO exhibits superior OER performance with an overpotential of 344 mV to achieve a current density of 100 mA cm⁻² in 1.0 M KOH, and the Tafel slope is as low as 47 mV dec⁻¹. The OER performance of Fe-NiS(2)/NrGO is better than that of commercial RuO₂. This work will eventually help to rationally design efficient transition-metal catalysts in future technologies for OER.