Synergy of Interface Coupling and Sulfur Vacancies in Ni₃S₂/Fe₂P for Water Splitting

Integrated application of interface engineering and vacancy engineering is a promising and effective strategy for the design and fabrication of high-performance electrocatalysts. Herein, the heterointerface catalyst with rich sulfur vacancies, v_s-Ni₃S₂/Fe₂P, was successfully designed and constructed. The strong heterointerface coupling and rich sulfur vacancies in v_s-Ni₃S₂/Fe₂P significantly optimize the electronic structure of the catalyst and synergistically improve the inherent catalytic activity. Benefiting from the optimization of the electronic structure, v_s-Ni₃S₂/Fe₂P exhibits excellent bifunctional electrocatalytic performance in alkaline electrolytes. The overpotentials for hydrogen and oxygen evolution reactions (HER and OER) are 99 and 169 mV at a current density of 10 mA cm^-2, respectively. Particularly, it achieves an ultrahigh OER performance with an overpotential of 251 mV at 300 mA cm^-2. Moreover, the catalyst also displays outstanding long-term durability. Density functional theory (DFT) computations reveal that the synergy of interface coupling and sulfur vacancies is crucial to optimizing the electronic structure. This study offers a hopeful pathway for the design and construction of durable and efficient electrocatalysts.