Rapid, self-sacrificing template synthesis of two dimensional high-entropy oxides toward high-performance oxygen evolution†

The design of high-entropy oxides (HEOs) with specific morphologies and tunable compositions is of great significance for the development of efficient electrocatalysts for the oxygen evolution reaction (OER). Herein, a series of two-dimensional HEOs with abundant active sites are prepared by a self-sacrificing template method via rapid Joule heating. Among them, high-entropy oxide (FeCoNiMoRu)₃O₄ exhibits outstanding OER performance with low overpotential (199 mV@10 mA cm^—2, 266 mV@100 mA cm^—2), small Tafel slope (40 mV dec^—1), and excellent long-term stability (operating at 500 mA cm^—2 for 100 hours without significant decay). The perfect performance of (FeCoNiMoRu)₃O₄ can be attributed to the large active surface area generated by the nanosheet structure, shortened ion transport pathway, entropy stabilization mechanism and multi-element synergism. Therefore, the two-dimensional high-entropy oxide prepared by using a carbon sacrificial template is expected to be a promising candidate material for industrial water splitting.