High-entropy alloy catalysts of FeCoNiCuMo/C with high stability for efficient oxygen evolution reaction

Abstract

In recent years, high-entropy alloy materials have garnered widespread attention in the field of water electrolysis catalysts, owing to their exceptional electrochemical performance. However, synthesizing efficient and highly stable catalysts remains a formidable challenge. This study presents the preparation of a highly stable FeCoNiCuMo/C high-entropy alloy catalyst, exhibiting an overpotential of 324 mV at a current density of 10 mA·cm−2 in a 1.0 M KOH solution, comparable to commercial RuO2. The Tafel slope reaches 70.5 mV·dec−1, and the charge transfer resistance is only 3.6Ω, demonstrating outstanding electrochemical performance. Furthermore, stability tests conducted over 72 h indicate the excellent stability of the prepared high-entropy alloy catalyst, with only a slight deviation observed after 5000 cycles of accelerated durability experiments. Theoretical calculations show that due to lattice distortion and cocktail effect, the d-band center of FeCoNiCuMo/C moves away from the Fermi surface compared to the pure component, which attenuates the adsorption of the reaction intermediates and leads to a significant decrease in the oxygen evolution reaction overpotential. This study validates the potential for long-term, efficient, and stable operation of high-entropy alloys as water electrolysis catalysts, providing experimental support for expanding the application scope of HEA.