Activating Ni/Co Sites in NiCo‐MOF via V ₂ O ₅ Nanosheet Integration for Enhanced Water Oxidation Reaction

Abstract A composite with enhanced electrochemical performance for the oxygen evolution reaction (OER) was prepared by forming a heterostructured NiCo metal–organic framework (MOF) on V 2 O 5 nanosheets using a simple two‐step hydrothermal approach. Detailed microstructural and surface analyses revealed a uniform distribution of NiCo MOF microplates on the V 2 O 5 nanosheets, confirming the structural modification responsible for faster charge transfer kinetics. The optimal NiCo MOF/V 2 O 5 electrocatalyst exhibited an OER overpotential of 280 mV at 20 mA cm −2 , a Tafel slope of 77.5 mV dec −1 , and a low charge transfer resistance ( R ct = 9.2 Ω). These quantitative improvements in OER performance were attributed to synergistic interfacial interactions, which increased the exposure of Ni/Co active sites to the electrolyte. The catalyst maintained a stable activity over 5000 cyclic voltammetry (CV) cycles and a 55‐h chronopotentiometry (CP) test, demonstrating its electrochemical durability. Furthermore, an asymmetric electrolyzer (Pt/C||NiCo MOF/V 2 O 5 ) incorporating the present catalyst achieved a cell voltage of 1.625 V at 10 mA cm −2 and maintained a stable performance during extended operation, confirming its potential for practical water splitting applications.