Self-reconstruction of (CoNiFeCuCr)Se high-entropy selenide for efficient oxygen evolution reaction

Abstract

High-entropy materials (HEMs) have emerged as promising candidates of electrocatalysts owing to their unique structural features. Herein, flower-like high-entropy selenide (CoNiFeCuCr)Se (F-HES) is prepared by a two-step solvothermal method. F-HES demonstrates outstanding oxygen evolution reaction (OER) activity compared to other high-entropy catalysts, characteristic of 252 mV@100 mA·cm−2 along with excellent stability of 50 h, profiting from its specific structure and wide mesoporous distribution. The performance surpasses their quaternary, ternary, binary and unary counterparts can be attributed to the synergistic interaction among multiple metal species. Further investigations reveal the formation of metal (oxy)hydroxide where Co and Ni are more easily activated and the adsorption of selenate during anodization. Density functional theory (DFT) calculations demonstrate high-entropy coordination environment and surface-adsorbed selenate result in the enhanced intrinsic activity of active site and faster reaction kinetics. Meanwhile, the presence of interfacial selenate also improves the wetability of catalyst surface. This work provides a promising platform to design novel, outstanding HEMs for practical water electrolysis.