La-doped high-entropy layered double hydroxides with reinforced active sites for ultra-stable oxygen evolution reaction

Developing non-noble metal catalysts with low cost, ease of scalability, high efficiency and stability under high current densities is crucial for the commercial production of green hydrogen in anion exchange membrane water electrolyzers (AEMWEs), which are limited by the slow kinetics of the anodic oxygen evolution reaction (OER). High-entropy layered double hydroxides (HE-LDHs) with the merits of optimized electron structures and multiple tunable active sites have emerged as a research hotspot. Herein, we successfully synthesized La-doped FeCoNiMn-LDH with remarkable performance, requiring only an ultralow overpotential of 162 ± 5.57 mV to achieve a current density of 100 mA cm −2 , outperforming the vast majority of non-noble metal-based electrocatalysts. Additionally, the as-prepared FeCoNiMnLa-LDH maintaining stable operation at 500 mA cm −2 for over 1000 h. Importantly, in AEMWEs, FeCoNiMnLa-LDH achieves an ultralow potential of 1.69 V at 1 A cm −2 and operates stably for 600 h without significant activity decay. In Operando EIS reveals the dynamic reconstruction of M 2+ into high-valent MOOH species during the OER, where synergistic multi-metal interactions and La doping-induced electronic modulation facilitate the formation of highly active γ-NiOOH and CoOOH, thereby significantly boosting catalytic activity. This study provides a foundational reference for the design and application of advanced high-entropy electrocatalysts.