Origin of Enhanced Oxygen Evolution in Restructured Metal–Organic Frameworks for Anion Exchange Membrane Water Electrolysis

Metal-Organic Frameworks (MOFs), praised for structural flexibility and tunability, are prominent catalyst prototypes for exploring oxygen evolution reaction (OER). Yet, their intricate transformations under OER, especially in industrial high-current environments, pose significant challenges in accurately elucidating their structure-activity correlation. Here, we harnessed an electrooxidation process for controllable MOF reconstruction, discovering that Fe doping expedites Ni(Fe) MOF structural evolution, accompanied by the elongation of Ni-O bonds, monitored by in situ Raman and UV/Visible spectroscopy. Theoretical modeling further reveals that Fe doping and defect-induced tensile strain in the NiO₆ octahedra augments the metal ds-O p hybridization, optimizing their adsorption behavior and augmenting OER activity. The reconstructed Ni(Fe) MOF, serving as the anode in anion exchange membrane water electrolysis, achieves a noteworthy current density of 3300 mA cm^-2 at 2.2 V while maintaining equally stable operation 500 mA cm^-2 for 300 h and 1000 mA cm^-2 for 170 h. This undertaking elevates our comprehension of OER catalyst reconstruction, furnishing promising avenues for designing highly efficacious catalysts across electrochemical platforms.