ABSTRACT High‐entropy intermetallics (HEIs) exhibit outstanding stability in alkaline water electrolysis, but their application as catalysts is strictly restricted by sluggish hydrogen evolution reaction (HER) kinetics. Hydrogen spillover offers a promising strategy to address this challenge, enabling timely replenishment of active hydrogen in alkaline media through migration from water dissociation sites to adjacent catalytic domains. Herein, we report a Sigma phase HEIs catalyst S‐MnFeCoNiVCu, where spillover carrier‐Cu incorporation into the high‐entropy topological close‐packed structure significantly enhances hydrogen spillover efficiency. This catalyst exhibits excellent HER performance in 1 m KOH, requiring only 161 and 266 mV to achieve current densities of 100 mA cm −2 and 500 mA cm −2 , respectively. The markedly reduced Tafel slope (46.93 mV dec −1 ) and enhanced hydrogen adsorption/desorption kinetics provide clear evidence of hydrogen spillover phenomena during HER. The inherent structural stability of Sigma phase HEIs ensures ultra‐durable operation over 6000 h at 500 mA cm −2 with no detectable degradation. This work demonstrates a novel catalyst design paradigm through synergistic structural engineering and spillover carrier element incorporation, offering fresh insights into hydrogen spillover‐enhanced alkaline HER.
Tian et al. (Sat,) studied this question.