One-Step Synthesis of Porous FeNiS_x Coupled with 1T/2H MoS₂ via Hydrazine Hydrate-Induced Phase Transformation for Hydrogen Evolution

Heterostructured catalysts with the potential synergies between the polymetallic sulfides and the construction of 1T-phase MoS2 are a promising alternative and contribute to obtain the enhanced hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performance. Herein, the porous hybrid nanostructures coupling FeS2 and NiS complexes with 1T/2H phase MoS2 (FeNiSx@MoS2-HZH(x)) are prepared via a facile one-pot pyrolysis strategy accompanied by hydrazine hydrate (HZH)-induced phase transformation without the assistance of a template. The hybrid nanostructures possessing crystalline-amorphous (c-a) interface need overpotentials of 139 mV to achieve the current density of 10 mA cm(-2) (eta(10)) in 0.5 M H2SO4, which have superior kinetics for the HER process with a Tafel slope value of 57.9 mV dec(-1). The 24 h continuous HER operated at eta(10) exhibits negligible deterioration, which has only a decrease of 3 mV at eta(10) after the 5000 cyclic voltammetry cycle tests, indicating the desirable stability of FeNiSx@MoS2-HZH(2). Beyond that, the resultant FeNiSx@MoS2 requires 335 mV at eta(10). Specifically, the electrochemical and structural characterization prove that the enhanced HER performance is contributed from the incorporation of HZH to form FeS2/MoS2/NiS heterostructures and c-a interface sites coupling with 1T/2H phase MoS2, which provide more exposed active sites benefiting from the larger surface area. The simple and convenient design strategy has certain enlightenment for the development of sustainable energy production.