Complementary Functions of Vanadium in Boosting Electrocatalytic Activity of CuCoNiFeMn High‐Entropy Alloy for Water Splitting

Abstract

AbstractHigh entropy alloys (HEAs) composed of multi‐metal elements in a single crystal structure are attractive for electrocatalysis. However, identifying the complementary functions of each element in HEAs is a prerequisite. Thus, VxCuCoNiFeMn (x = 0, 0.5, and 1.0) HEAs are investigated to identify the active role of vanadium in improving the electrocatalytic activity for the hydrogen evolution reaction (HER). Structural studies show the successful incorporation of V in the HEA. V1.0CuCoNiFeMn (V1.0‐HEA) shows an overpotential of 250 mV versus the reversible hydrogen electrode (at −50 mA cm−2, 1 m KOH), which is ≈170 mV lower than that of control‐HEA (422 mV). Improves electrical conductivity and the electrochemical surface area of the V1.0‐HEA accelerated HER activity. Furthermore, density functional theory calculations reveal reduced water dissociation and hydrogen adsorption energies of V1.0‐HEA, resulting in the boosted HER kinetics. The effect of V incorporation on the barrier height and active sites at the surface of V1.0‐HEA is schematically explained. This study can be facilitated for the development of highly active HEAs for large‐scale electrochemical water splitting.