Fe3O4@NiSx/rGO composites with amounts of heterointerfaces and enhanced electrocatalytic properties for oxygen evolution

The sluggish oxygen evolution kinetics involved in water splitting and various metal-air batteries makes the effective and inexpensive electrocatalysts be highly desirable for oxygen evolution reaction (OER). Herein, an effective and facile two-step route is developed to construct Fe3O4@NiSx composite loaded on reduced graphene oxide (rGO). The morphology and microstructure of the composites were characterized by different characterization techniques. The obtained composites show amounts of heterointerfaces. The shift of binding energy in X-ray photoelectron spectrum demonstrates the existence of interfacial charge transfer effect between Fe3O4 and NiSx. The optimized Fe3O4@NiSx/rGO sample exhibits excellent electrocatalytic performance toward OER in alkaline media, showing 10 mA·cm−2 at η = 330 mV, lower Tafel slope (35.5 mV·dec−1), and good durability, demonstrating a great perspective. The excellent OER performance can be ascribed to the synergetic effect between Fe and Ni species. It is believed that the heterointerfaces between Fe3O4 and NiSx perform as active centers for OER.