Synergistic construction of a FeCoNiCuAl-S high entropy sulfide by mechanical alloying–hydrothermal sulfidation and its application in efficient OER catalysis

Abstract

High-entropy sulfide (high-entropy sulfide, HES) has attracted extensive attention in recent years as a unique oxygen evolution reaction (oxygen evolution reaction, OER) catalyst. HES has unique electronic structure regulation ability and excellent electrochemical stability, but the low cost and simple preparation of this material are still a challenge. In this study, the FeCoNiCuAl-S high-entropy sulfide was successfully constructed by combining high-energy ball milling and hydrothermal sulfidation as a synergistic strategy. The experimental results show that the electrocatalyst (HES-S5) prepared when the concentration of thiourea is 5 mM has the best morphology, structure and performance. In 1 M KOH, the HES-S5 electrode only needs an overpotential of 189.98 mV to obtain a current density of 10 mA cm⁻² and can maintain long-term stable operation. The experimental results show that in addition to the excellent performance of the catalyst brought by the inherent structure of the HES, the reconstruction of the surface composition and structure of the catalyst during the OER process further improves the catalytic performance of the catalyst. This universal synthesis strategy demonstrates the great potential of HES catalysts as OER electrocatalysts and provides new ideas for the controllable preparation of high-entropy compound catalysts.