Fe‐doped Ni₃S₂@CoSx nanoarrays derived from MOF as bifunctional electrocatalysts for efficient overall water‐splitting

BACKGROUND Fabricating high‐performance bifunctional electrocatalysts remains challenging to promote the development of electrocatalytic water‐splitting. RESULT A heterostructure Fe‐Ni 3 S 2 @CoS x /NF was successfully synthesized using an interfacial engineering strategy. Benefiting from the strong synergistic effect between highly active cobalt sulfide (CoS x ) and iron‐doped trinickel‐disulfide (Ni 3 S 2 ) (Fe‐Ni 3 S 2 ), Fe‐Ni 3 S 2 @CoS x /NF exhibited outstanding bifunctional performance, with low overpotentials of 77 and 217 mV for the cathodic hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER), respectively, at 10 mA cm −2 . CONCLUSION The CoS x nanoarrays and Fe‐Ni 3 S 2 nanosheets respectively served as HER and OER active centers. When Fe‐Ni 3 S 2 @CoS x /NF was used as both cathode and anode for overall water‐splitting, a low voltage of 1.52 V was required to reach the current density of 10 mA cm −2 with nearly 100% Faradic efficiency and outstanding durability.