Deconstructing Amorphous MoS ₂ ‐Crystalline Ni ₃ S ₂ Heterostructures Toward High‐Performance Alkaline Water Splitting

ABSTRACT Developing low‐cost and efficient catalysts for sustainable hydrogen (H 2 ) production to the reliance on precious metal is an important trend in the future development of catalysts. Herein, a simple in‐situ one‐step hydrothermal strategy is employed to modify the outer layer of Ni 3 S 2 crystals with amorphous MoS 2 to construct core‐shell heterostructures and heterogeneous interfaces, which promotes the chemisorption of intermediates, including hydrogen and oxygen, and realizes the coupling enhancement of hydrogen‐evolution reaction (HER) and oxygen‐evolution reaction (OER) in alkaline water electrolysis process. In 1.0 M KOH electrolyte, the overpotentials of the electrodes are 78 mV (HER) and 245 mV (OER) at a current density of 10 mA cm −2 , respectively. At the same time, the electrode has excellent stability for more than 100 h at a current density of 100 mA cm −2 , due to the amorphous structure. In addition, when used as an anode and cathode to form an electrolyzer, a cell voltage of only 1.5 V is required to produce a current density of 10 mA cm −2 . This study demonstrates that the constructed amorphous heterostructured interface synergistically promotes the dissociation of water and the adsorption of intermediates, providing a deep insight on how to accelerate the development of efficient catalysts.