Fe-Doped Ni3S2/NixP Heterojunction with Enhanced Electron Transfer for Efficient Electrochemical Water Splitting

Electrochemical water splitting is a significant energy conversion process to produce sustainable and green hydrogen, which demands highly active, highly durable, and low-cost hydrogen evolution reaction (HER)/oxygen evolution reaction (OER) electrocatalysts. Transition metal sulfides (TMS) have been widely explored as low-cost bifunctional catalysts for electrochemical water splitting, but their activities and stabilities are not satisfactory. Herein, we report a facile two-step synthesis of Fe-doped Ni 3 S 2 /Ni x P heterojunction on nickel foam (denoted as Fe–Ni 3 S 2 /Ni x P/NF) by first solvothermal and then phosphorization. Phosphorization treatment provides Fe–Ni 3 S 2 /Ni x P/NF with a rough surface with a nanorod array morphology and enhanced electron transfer. Compared to the nonphosphorized samples (Fe–Ni 3 S 2 /NF) and noble metal-based benchmark catalysts, Fe–Ni 3 S 2 /Ni x P/NF exhibits superior OER, HER, and overall water splitting performances with low overpotentials and nearly unchanged potential after durability tests. This work sheds new light on the design of high-performance bifunctional TMS-based nanomaterials toward electrocatalytic water splitting.