Self‐Armoring Non‐Noble High‐Entropy Alloys with CNT Networks for Ultra‐Stable Acid Water Electrolysis

ABSTRACT Recent advances in high‐entropy alloys (HEA) have demonstrated that the electrocatalytic performance of non‐noble metals can be enhanced to levels comparable to those of noble metals through the synergistic effects of multiple elements. However, non‐noble HEA systems still encounter inherent stability challenges caused by electrolyte corrosion, particularly under acidic conditions. Here, a highly stable non‐noble HEA catalyst for acid water electrolysis is realized through self‐armoring them with a self‐supporting and self‐protecting 3D interlocking CNT network. The CNT networks confer robust chemical corrosion resistance to the catalyst, while the synergistic effects of the multi‐element composition enable the catalyst to have superior electrocatalytic activity. Remarkably, the catalyst maintains stable operation for over 600 h without significant performance decay. The overpotentials of 48 and 226 mV at 10 mA cm −2 in 0.5 M H 2 SO 4 for the hydrogen evolution reaction and the oxygen evolution reaction are achieved, respectively. This self‐armoring strategy establishes a pathway to overcome intrinsic stability limitations in non‐noble HEA catalysts, supporting scalable deployment of non‐noble HEA under aggressive electrochemical environments.