Unveiling Dynamic Surface Transformations: Mo-Doped Fe-Based MOFs as Next-Generation Oxygen Evolution Catalysts

Abstract

Unlocking the full potential of metal-organic frameworks (MOFs) for water-splitting applications requires innovative strategies to enhance their catalytic efficiency and stability. Here, we introduce a Mo-doped Fe-based MOF (MoFe-NH2-BDC) with a unique 2D nanosheet and plate-like morphology to revolutionize the oxygen evolution reaction (OER). Mo incorporation optimizes electronic properties, accelerates charge transfer, and dynamically reconstructs the catalyst surface into highly active FeOOH species, ensuring long-term performance. This next-generation electrocatalyst achieves an ultra-low overpotential of 254 mV at 20 mA cm‒2, with a rapid Tafel slope of 66 mV dec‒1, surpassing conventional RuO2 catalysts. Operando Raman and ATR-FTIR spectroscopy reveal that Mo facilitates an adsorbate evolution mechanism (AEM), stabilizing intermediates and boosting reaction kinetics. In a practical two-electrode system, MoFe-NH2-BDC (+) || Pt/C (−) demonstrates an exceptional cell voltage of 1.58 V at 100 mA cm‒2, maintaining stability for 85 h. These results underscore the transformative impact of Mo doping in MOFs, paving the way for highly efficient, durable, and scalable electrocatalysts for sustainable energy applications.