Bifunctional high-entropy alloy electrocatalysts for stable overall water splitting at industrial-level current densities†

Abstract

High-entropy materials offer a wide range of potential applications in the catalysis domain due to their multi-active site characteristics and cocktail effect. However, the development of bifunctional electrocatalysts with both superior efficiency and excellent stability under both industrial preparation and industrial running conditions remains a significant challenge. Herein, a scalable plasma spraying strategy is developed to fabricate FeCoNiCrMn HEA catalysts with multimetal synergy, enabling robust bifunctional activity for oxygen and hydrogen evolution reactions (OER/HER). The HEA exhibits ultralow overpotentials of 220 mV (OER) and 69 mV (HER) at 10 mA cm⁻², alongside exceptional durability over 1000 h (OER) and 500 h (HER) at 1000 mA cm⁻². In an anion exchange membrane water electrolyzer (AEMWE), the HEA achieves 1000 mA cm⁻² at merely 2.18 V, outperforming commercial Ni mesh (3.40 V) and Raney Ni (3.03 V) electrode systems. Crucially, stable operation for 200 h at 1000 mA cm⁻² under industrial conditions (1 M KOH, 80 °C) demonstrates the viability of scalable HEA catalysts for practical water splitting. This work bridges the gap between lab-scale innovation and industrial electrocatalyst deployment, offering a promising pathway for large-scale hydrogen production.