Top‐Level Design Strategy to Construct an Advanced High‐Entropy Co–Cu–Fe–Mo (Oxy)Hydroxide Electrocatalyst for the Oxygen Evolution Reaction

Abstract High‐entropy materials are new‐generation electrocatalysts for water splitting due to their excellent reactivity and highly tailorable electrochemical properties. Herein, a powerful top‐level design strategy is reported to guide and design advanced high‐entropy electrocatalysts by establishing reaction models (e.g., reaction energy barrier, conductivity, adsorption geometries for intermediates, and rate‐determining step) to predict performance with the help of density functional theory (DFT) calculations. Accordingly, novel high‐entropy Co–Cu–Fe–Mo (oxy)hydroxide electrocatalysts are fabricated by a new low‐temperature electrochemical reconstruction method and their oxygen evolution reaction (OER) properties are thoroughly characterized. These as‐prepared quaternary metallic (oxy)hydroxides present much better OER performance than ternary Co–Cu–Mo (oxy)hydroxide, Co–Fe–Mo (oxy)hydroxide, and other counterparts, and are demonstrated with a low overpotential of 199 mV at a current density of 10 mA cm−2 and a 48.8 mV dec−1 Tafel slope in 1 m KOH and excellent stability without decay over 72 h. The performance enhancement mechanism is also unraveled by synchrotron radiation. The work verifies the usefulness of high‐entropy design and the great synergistic effect on OER performance by the incorporation of four elements, and also provides a new method for the construction of advanced high‐entropy materials for energy conversion and storage.