Interface Engineering: Heterogeneous Nickel–Iron Sulfide Decorated Nitrogen‐Doped‐Graphene for Efficient Water Splitting

It is urgent to develop non precious metal electrode materials with significant efficiency and ultrahigh stability to meet the growing demand for renewable energy conversion devices. Herein, heterogeneous nickel–iron sulfide decorated nitrogen‐doped‐graphene ((Ni,Fe)–Sx–Fe/NGr) with regulated local electronic structure, rich defects, and honeycomb shaped geometric form is synthesized using facile solvothermal and annealing phase transition technology. The obtained target catalyst was characterized for use in a water splitting device, revealing that (Ni,Fe)–Sx–Fe/NGr has lower overpotentials (203 (OER)/166 mV (HER)) for oxygen and hydrogen evolution reaction (OER and HER) compared to NiFeSx (235 (OER)/235 mV (HER)) and NiFe LDH (255 (OER)/308 mV (HER)) at 10 mA/cm 2 , as well as most reported electrode materials. Meanwhile, (Ni,Fe)–Sx–Fe/NGr demonstrated excellent geometric/chemical stability after 210 h long‐term stability testing. Typically, as a dual‐functional overall water‐splitting electrode, (Ni,Fe)–Sx–Fe/NGr demonstrates lower driving voltage (1.44 V) and considerable stability (110 h) at 10 mA/cm 2 . Therefore, the developed bimetallic sulfide coupled nitrogen doped graphene with notable activity and stability provides a reference for green and efficient industrial production of green hydrogen.