Fe-Doped Ni₃S₂/Ni_<i>x</i>P Heterojunction\nwith Enhanced Electron Transfer\nfor Efficient Electrochemical Water Splitting

Abstract

Electrochemical water splitting is a significant energy\nconversion\nprocess to produce sustainable and green hydrogen, which demands highly\nactive, highly durable, and low-cost hydrogen evolution reaction (HER)/oxygen\nevolution reaction (OER) electrocatalysts. Transition metal sulfides\n(TMS) have been widely explored as low-cost bifunctional catalysts\nfor electrochemical water splitting, but their activities and stabilities\nare not satisfactory. Herein, we report a facile two-step synthesis\nof Fe-doped Ni₃S₂/Ni_<i>x</i>P heterojunction on nickel foam (denoted as Fe–Ni₃S₂/Ni_<i>x</i>P/NF) by first solvothermal\nand then phosphorization. Phosphorization treatment provides Fe–Ni₃S₂/Ni_<i>x</i>P/NF with a rough\nsurface with a nanorod array morphology and enhanced electron transfer.\nCompared to the nonphosphorized samples (Fe–Ni₃S₂/NF) and noble metal-based benchmark catalysts, Fe–Ni₃S₂/Ni_<i>x</i>P/NF exhibits\nsuperior OER, HER, and overall water splitting performances with low\noverpotentials and nearly unchanged potential after durability tests.\nThis work sheds new light on the design of high-performance bifunctional\nTMS-based nanomaterials toward electrocatalytic water splitting.