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

Abstract

Heterostructured catalysts with the potential synergies between the polymetallic sulfides and the construction of 1T-phase MoS 2 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 FeS 2 and NiS complexes with 1T/2H phase MoS 2 (FeNiS x @MoS 2 −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 (η 10 ) in 0.5 M H 2 SO 4 , 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 η 10 exhibits negligible deterioration, which has only a decrease of 3 mV at η 10 after the 5000 cyclic voltammetry cycle tests, indicating the desirable stability of FeNiS x @MoS 2 −HZH 2 . Beyond that, the resultant FeNiS x @MoS 2 requires 335 mV at η 10 . Specifically, the electrochemical and structural characterization prove that the enhanced HER performance is contributed from the incorporation of HZH to form FeS 2 / MoS 2 /NiS heterostructures and c−a interface sites coupling with 1T/2H phase MoS 2 , 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.