A Novel Multinary Intermetallic as an Active Electrocatalyst for Hydrogen Evolution

Abstract Electrochemical water splitting offers an attractive approach for hydrogen production. However, the lack of high‐performance cost‐effective electrocatalyst severely hinders its applications. Here, a multinary high‐entropy intermetallic (HEI) that possesses an unusual periodically ordered structure containing multiple non‐noble elements is reported, which can serve as a highly efficient electrocatalyst for hydrogen evolution. This HEI exhibits excellent activities in alkalinity with an overpotential of 88.2 mV at a current density of 10 mA cm −2 and a Tafel slope of 40.1 mV dec −1 , which are comparable to those of noble catalysts. Theoretical calculations reveal that the chemical complexity and surprising atomic configurations provide a strong synergistic function to alter the electronic structure. Furthermore, the unique L1 2 ‐type ordered structure enables a specific site‐isolation effect to further stabilize the H 2 O/H* adsorption/desorption, which dramatically optimizes the energy barrier of hydrogen evolution. Such an HEI strategy uncovers a new paradigm to develop novel electrocatalyst with superior reaction activities.