Synergy of Interface Coupling and Sulfur Vacancies in NiS/FeP 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-NiS/FeP, was successfully designed and constructed. The strong heterointerface coupling and rich sulfur vacancies in v-NiS/FeP significantly optimize the electronic structure of the catalyst and synergistically improve the inherent catalytic activity. Benefiting from the optimization of the electronic structure, v-NiS/FeP 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, respectively. Particularly, it achieves an ultrahigh OER performance with an overpotential of 251 mV at 300 mA cm. 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.