Engineered interface of three-dimensional coralliform NiS/FeS2 heterostructures for robust electrocatalytic water cleavage

Heterojunction structures improve the intrinsic activity of electrocatalysts by enhancing the charge transfer between the catalyst and the electrode. In this paper, the NiS/FeS 2 heterostructured electrocatalyst is fabricated by a simple sulfidation method using an interface engineering strategy to adjust the surface electron density of the electrocatalyst. As expected, NiS/FeS 2 electrocatalyst exhibits superior activity and durable oxygen evolution reaction (OER) stability, requiring only a low overpotential of 183 mV to achieve a current density of 10 mA·cm −2 and can be stable for more than 80 h, superior to NiS, FeS 2 electrocatalyst individually, and precious RuO 2 . Notably, NiS/FeS 2 is also a good bifunctional electrocatalyst with good overall water splitting performance, and it only requires a voltage 1.56 V to obtain a current density of 10 mA·cm −2 for more than 12 h. Remarkably, the NiS/FeS 2 hybridization facilitates the formation of coral-like structures, increasing the electrochemical surface area (ECSA) and enhancing the charge transfer efficiency, thus leading to excellent electrocatalytic performance. This work proposes a constructive strategy for designing efficient electrocatalysts based on interface engineering, and lays a foundation for designing a new class of electrocatalysts.