Dynamic Dissolution-Replenishment Equilibrium Enables Efficient and Durable Oxygen Evolution on Self-Reconstructing High-Entropy Alloys.

Abstract

Achieving an efficient and stable oxygen evolution reaction (OER) at industrial current densities remains challenging for non-noble electrocatalysts due to irreversible surface degradation under harsh oxidative conditions. Here, we report a FeCoNiCrW0.6 dual-phase high-entropy alloy electrocatalyst that undergoes controllable in situ surface reconstruction during high-current-density OER, enabling simultaneous high activity and exceptional durability. The reconstruction generates a honeycombed porous architecture covered by a multicomponent amorphous oxide layer, which promotes a transition from the adsorbate evolution mechanism to the lattice oxygen mechanism, thereby enhancing the intrinsic activity. More importantly, the catalyst maintains long-term stability through a dynamic dissolution-replenishment equilibrium, in which selective leaching of W and Cr from the underlying FCC matrix continuously regenerates the surface-active layer, while the high-entropy effect suppresses excessive degradation. As a result, the reconstructed catalyst delivers a low overpotential of 223 mV at 10 mA cm-2 and stable operation for over 700 h at ampere-level current densities. When implemented into an anion-exchange membrane electrolyzer, it enables efficient alkaline and seawater electrolysis at 1 A cm-2 with a low cell voltage of 1.79 V and excellent durability. This work establishes a dynamic self-reconstruction paradigm for designing stable, high-performance electrocatalysts for industrial water electrolysis.