Pinning Effect Suppresses Leaching in High-Entropy Amorphous Alloys for Efficient Selective Electrocatalysis in Alkaline Seawater.

Abstract

Simultaneously achieving enhanced selectivity of the oxygen evolution reaction (OER) and long-term catalytic activity remains a critical challenge in seawater electrolysis. Although anion layers (e.g., MoO₄^2-/CrO₄^2-) electrochemically reconstructed from multivalent metals (Cr, Mo) shield Cl^- and suppress the competitive chlorine evolution reaction (CER), continuous leaching of active elements causes structural collapse. Thus, the concerted regulation of reconstruction kinetics and leaching suppression is essential for achieving stable electrocatalysis. In this study, a designed FeCoNiCrMo high-entropy amorphous alloy catalyst is prepared to significantly enhance OER selectivity and suppress active element leaching, enabling long-term stable electrocatalysis in alkaline seawater electrolysis. In alkaline simulated seawater (1 M KOH + 0.5 M NaCl), this catalyst achieves a low overpotential of 223 mV at 10 mA cm^-2, matching pure alkaline electrolyte (221 mV). Combined ion chromatography (IC) characterization of Cl^- variation and faradaic efficiency analyses confirm its inhibition effect on the CER. The assembled alkaline seawater electrolyzer exhibits high stability, operating for 1200 h at 500 mA cm^-2 with a low voltage decay rate of 0.118 mV h^-1. Theoretical and in situ characterizations reveal that the short-range ordered domains in the amorphous phase synergistically suppress the leaching of active elements through pinning effect, thereby conferring outstanding structural stability.