Zwitterion-Modified NiFe OER Catalyst Achieving Ultra-Stable Anion Exchange Membrane Water Electrolysis via Dynamic Alkaline Microenvironment Engineering

Abstract

The development of efficient non-precious metal electrocatalysts for industrial anion exchange membrane water electrolysis (AEM-WE) remains challenging, primarily due to sluggish OH– transfer from the anion exchange membrane (AEM) to catalytic sites, causing H+ accumulation and performance degradation. Herein, we developed a zwitterion-modified NiFe catalyst (z-NiFe) through gradient soaking, facilitates rapid OH– transfer across the AEM-electrocatalyst interface, effectively neutralizing the generated H+ and enhancing catalytic performance. In-situ Raman spectroscopy and OH− conductivity measurements reveal an alkaline-enriched surface environment, which inhibits H+ accumulation-induced chemical corrosion and enhances water oxidation performances. Density functional theory (DFT) analysis demonstrates that zwitterions stabilize adsorbed oxygen during catalysis, and reduce the overpotential of oxygen evolution reaction (OER). The z-NiFe shows an ultralow Tafel slope (28.5 mV dec−1) and high activity (190 mV overpotential at 1,000 mA cm−2) in 1 M KOH. When integrated into an AEM-WE system, the z-NiFe-catalysed AEM-WE device exhibits a low cell voltage of 1.76 V at 1,000 mA cm−2 and record-breaking durability over 14,000 h, with a voltage degradation rate of 12.3 μV h−1, representing a significant advancement in AEM-WE technology.