In situ construction of self-supporting Ni–Fe sulfide for high-efficiency oxygen evolution

Abstract

The development of efficient and cost-effective electrocatalysts for the oxygen evolution reaction (OER) is promising for the practical application of high-performance water-splitting and rechargeable metal–air batteries. In this paper, two-dimensional (Fe,Ni)₃S₄ nanosheet arrays vertically growing on iron foam are simply synthesized via an in situ construction strategy. (Fe,Ni)₃S₄ features a self-supporting structure with numerous mesopores. As an OER catalyst, (Fe,Ni)₃S₄ obtained at 110 °C ((Fe,Ni)₃S₄-110) not only exhibits excellent OER activity but also superior reaction stability even at a high current density of 50 mA cm⁻². Besides, the excellent reaction kinetics of the self-supporting electrodes are also demonstrated via Tafel plots and C_dl calculations. The excellent OER performance of the self-supporting Ni–Fe sulfides is mainly ascribed to the excellent mesopore-containing 2D nanosheets assembled in the self-supporting structure and the combined advantages of the binary metal species, which obviously improved the mass transfer and intrinsic properties. This simple synthetic strategy is conducive to establishing self-supporting catalysts, which can be widely applied in the energy conversion field.