Dual-engineering of defect and substrate in FeNi-MOFs for efficient and durable oxygen evolution reaction

The development of highly efficient, economical, and robust oxygen evolution reaction (OER) electrocatalysts is imperative for the advancement of sustainable hydrogen production through water electrolysis. In this study, a dual regulation strategy is developed by integrating coordination defect engineering with substrate regulation. Competitive coordination between salicylic acid (SA) and 2,5-dihydroxyterephthalic acid (DOBDC) introduces controlled coordination defects and coordinatively unsaturated Fe and Ni sites, promotes asymmetric charge redistribution, and facilitates electrochemical reconstruction into active FeOOH/NiOOH phases. Meanwhile, the Fe foam (FF) substrate provides interfacial Fe species that regulate catalyst nucleation and local metal composition, while its porous conductive framework strengthens catalyst adhesion and enhances interfacial charge transfer. The dual-regulated FeNi-SA₃/FF catalyst exhibits superior OER performance, requiring only 213 mV of overpotential to reach 10 mA cm^-2 and maintaining robust catalytic stability for 290 h. This work reveals the synergistic role of defect engineering and interfacial regulation, providing a rational strategy for developing non-noble metal electrocatalysts derived from metal organic frameworks for sustainable energy conversion.