Micro‐Galvanic‐Driven Scalable Synthesis of Heterostructured Nanoarrays for Durable Anion Exchange Membrane Water Electrolysis

Abstract The scalable synthesis of alkaline hydrogen evolution (HER) electrocatalysts that integrate high activity with operational durability is essential for advancing practical anion exchange membrane water electrolysis (AEMWE). Herein, vertical Cu‐MoNi₄ heterostructures are fabricated via a self‐driven galvanic‐corrosion‐coupled low‐temperature reduction strategy, circumventing hydrothermal protocols for scalable electrode fabrication. The catalyst achieves a low overpotential of 276 mV and exceptional stability for up to 2000 h at an ampere‐level current density of 1 A cm⁻² in 1 m KOH. Integrated in situ Raman and theoretical calculation unveil dual HER‐enhancing mechanisms in Cu‐MoNi₄: interfacial water restructuring activates O─H bond cleavage through electric‐field‐driven free water generation, while heterointerface charge redistribution synergistically lowers the dissociation barrier and optimizes hydrogen adsorption energy. When deployed as the cathode in an AEMWE device, the electrolyzer delivers industrial‐grade current densities of 1 A and 3.2 A cm⁻² at low cell voltages of 1.74 and 2.0 V at 60 °C, respectively, while exhibiting durable operation over 1000 h at 500 mA cm⁻². This study develops a scalable electrode fabrication protocol, advancing AEMWE technology for green hydrogen production within sustainable energy ecosystems.