Deconstructing Amorphous MoS₂-Crystalline Ni₃S₂ Heterostructures Toward High-Performance Alkaline Water Splitting

Developing low-cost and efficient catalysts for sustainable hydrogen (H₂) 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 Ni₃S₂ crystals with amorphous MoS₂ 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.