Ni(OH)₂-derived lamellar MoS₂/Ni₃S₂/NF with Fe-doped heterojunction catalysts for efficient overall water splitting

Heterostructures formed by combining semiconductor materials with different band structures can provide work functions, d-band positions and electronic properties different from bulk materials and are considered as an effective strategy to improve the catalytic activity through electronic modification. In this study, an efficient MoS₂/Fe-Ni₃S₂/NF heterojunction material was prepared by a two-step hydrothermal method. With the help of flake Ni(OH)₂ synthesized in the first step, growth sites were provided for flake Ni₃S₂. The electronic structure of Ni₃S₂ was optimized by Fe doping, while the construction of the MoS₂/Fe-Ni₃S₂ heterostructure allowed the catalyst to expose more active sites. MoS₂/Fe-Ni₃S₂/NF exhibited a small charge transfer resistance and excellent electrocatalytic performance. At a current density of 10 mA cm^-2, only low overpotentials of 148 mV and 118 mV were required for the oxygen precipitation reaction (OER) and hydrogen precipitation reaction (HER), respectively. Notably, when MoS₂/Fe-Ni₃S₂/NF is used as the anode and cathode for overall hydrolysis, only 1.51 V is required to reach a current density of 10 mA cm^-2, demonstrating its great potential for application in hydrolysis. This work provides a feasible idea for the rational construction of non-precious metal bifunctional electrocatalysts with excellent performance.