Interface Engineering Effected Charge Redistribution within High Entropy Alloy‐Metal Heterostructured Catalyst Enables High Performance Anion Exchange Membrane Water Electrolysis

Development of low-cost, highly efficient and stable catalysts is critical for the prevalence of anion exchange membrane water electrolysis (AEMWE) technology for green hydrogen production. High entropy alloy (HEA)-metal heterostructures (HEA-Mo), taking advantage of the versatile active sites and multiple synergies between constituent elements of HEA and interfacial electronic interactions between HEA and metal, are promising bifunctional catalysts for high-performance water electrolysis. Here, a FeCoNiCuMo HEA-Mo heterostructured catalyst is synthesized, through supersaturation-induced phase separation, for both anode and cathode of an AEMWE. The catalyst exhibits outstanding hydrogen evolution reaction (HER) (η₁₀/η₅₀₀ of 24/140 mV) and oxygen evolution reaction (OER) (η₁₀/η₅₀₀ of 175/325 mV) activities in 1 m KOH. The HEA-Mo//HEA-Mo based AEMWE delivers an ultrahigh current density of 2207 mA cm^-2 at 2.0 V and maintains stable operations at a commercially relevant high current density of 500 mA cm^-2 for 100 h with only 3.1% decay, demonstrating its excellent operation stability. HER activities are greatly enhanced through modulation of charge distributions with the decorated Mo, leading to better balanced hydrogen adsorption/desorption, together with the team up of Mo, a strong OH^- adsorbent, for enhanced water dissociation to accelerate both the Volmer and Heyrovsky steps.