Ni3S2-Co9S8 heterostructure nanowires supported on Ni foam as highly efficient and stable electrocatalyst for oxygen evolution reaction

Designing and synthesizing highly efficient, stable and inexpensive electrocatalysts for oxygen evolution reaction (OER) is a significant research topic for the development of clean energy. Herein, a catalyst of Ni3S2-Co9S8 heterostructure nanowires supported on nickel foam is fabricated by a two-step hydrothermal method. The catalyst shows excellent OER activity with an overpotential of only 294 mV at 20 mA cm−2, which may be attributed to the defective heterointerfaces between the metallic Co9S8 and Ni3S2 nanocrystalline grains. This efficient strategy for preparing Ni3S2-Co9S8 heterostructure catalyst can shed some light on the design of noble metal-free electrocatalysts. The performances for electrocatalytic oxidation of H2O2 on the electrodes are studied, and the results indicate that the step of –OOH oxidation in OER is a fast kinetics process and not the rate-determining step.