Self‐Reconstruction of High Entropy Alloys for Efficient Alkaline Hydrogen Evolution

Alkaline water (H₂O) electrolysis is currently a commercialized green hydrogen (H₂) production technology, yet the unsatisfactory hydrogen evolution reaction (HER) performance severely limits its energy conversion efficiency and cost reduction. Herein, PtRu_2.9Fe_0.15Co_1.5Ni_1.3 high entropy alloys (HEAs) is synthesized and subsequently exploited electrochemically induced structural oxidation processes to construct self-reconfigurable HEAs, as an efficient alkaline HER catalyst. The optimized self-reconstructed PtRu_2.9Fe_0.15Co_1.5Ni_1.3 HEAs with the HEAs and cobalt rutheniate interface (HEAs-Co₂RuO₄) exhibits excellent alkaline HER performance, requiring just 11.8 mV to obtain a current density (j) of 10 mA cm^-2 in 1 m KOH. And the j on HEAs-Co₂RuO₄ is 41.8 mA cm^-2 at 0.07 V_RHE, 2.0 and 6.1 times higher than PtRu_2.9Fe_0.15Co_1.5Ni_1.3 HEAs and 20% Pt/C. Mechanism studies reveal that the improved alkaline HER performance of HEAs-Co₂RuO₄ is due to the formation of HEAs-Co₂RuO₄, which significantly shrinks the Helmholtz layer, provides a new fast material transport channel, boosts H₂O adsorption, and reduces hydrogen adsorption, and thus accelerates the alkaline HER. This research not only throws new light on the self-reconstruction of catalysts but also provides guidance for the rational design of efficient electrocatalysts.