The design and construction of Co(OH)2@NiFe-MIL/NFF heterostructure catalyst for efficient and ultrastable water oxidation

Metal-organic frameworks (MOFs) are regarded as intriguing candidates for oxygen evolution reaction (OER) in electrocatalytic water splitting due to their unique intrinsic features. However, the unsatisfactory catalytic activity and stability are the stumbling blocks to practical alkaline water electrolysis application. Herein, a facile strategy is deployed to fabricate heterostructured electrocatalyst composed of Co(OH)2 nanosheets and the in situ produced bimetallic MOF (NiFe-MIL) using ferronickel foam (NFF) as both the metal source and the conductive substrate. The hybrid Co(OH)₂@NiFe-MIL/NFF demonstrates superior OER electrocatalytic activity, achieving a low overpotential of 230 mV (at 10 mA cm⁻²), a minimal Tafel slope of 12.79 mV dec⁻¹, and exceptional long-term stability. The exceptional catalytic activity and stability stem from the synergistic effect of heterogeneous interfacial structure and multiple active sites. The work establishes a novel paradigm for designing advanced electrocatalysts through rational manipulation of electronic structure.