Polymetallic foam-supported NiCrFeAlZn high-entropy electrodes with multi-site synergistic catalysis for ampere-level AEM water electrolysis

Polymetallic foam-supported multiscale porous NiCrFeAlZn HEA is fabricated via Zn-driven selective dealloying strategy. • NiCrFeAlZn delivers 3000 mA/cm 2 at 1.8 V, and runs stably for 1200 h at 1000 mA/cm 2 with an ultralow decay rate of 48.3 μV/h. • Multi-site synergistic catalysis on NiCrFeAlZn mitigates active-site poisoning from excessive adsorption of intermediates. Self-supporting high-entropy alloys (HEAs) present great application potential for anion exchange membrane water electrolysis (AEMWE), but still confront challenges in achieving efficient gas-liquid mass transfer while mitigating interfacial delamination under ampere-level current densities. Herein, an integrated NiCrFeAlZn HEA embedded within the substrate interior is fabricated by liquid-solid alloying between polymetallic NiCrFeAl foam and deposited Zn, followed by chemical Zn etching. The resultant bark-like architecture with multiscale pore networks and superaerophobic-superhydrophilic surfaces accelerates electrolyte infiltration, gas bubble detachment, and reaction kinetics toward overall water electrolysis. Accordingly, the bifunctional NiCrFeAlZn-based AEMWE achieves an ampere-level current density of 3000 mA/cm 2 at 1.8 V, and exhibits robust durability over 1200 h at 1000 mA/cm 2 with a degradation rate of 48.3 μV/h. In situ Raman spectroscopy and theoretical calculations reveal a multi-site synergistic catalysis mechanism. Al and Cr function as active centers for water dissociation and OH - adsorption; Ni and Fe promote the conversion of key intermediates toward H 2 and O 2 generation; Zn and Al act as electron donors to modulate the electronic structure and reduce the reaction energy barrier. This Zn-driven selective dealloying protocol based on polymetallic foams for fabricating bifunctional high-entropy electrodes with multi-site synergy holds great promise for AEMWE applications. Download: Download high-res image (194KB) Download: Download full-size image An integrated NiCrFeAlZn high-entropy alloy immobilized on polymetallic foam with multiscale pore structures and multisite synergistic catalytic is fabricated via a Zn-induced selective dealloying route for ampere-grade AEM water electrolysis