Catalytically Active Bimetallic Nickel–Cobalt MOF Linked Via Pyridine 2, 6-Dicarboxylate for Electrochemical Water Splitting Applications

Decomposition of water under higher current density is crucial for effective long-term generation and commercial consumption of hydrogen. Metal–organic frameworks (MOFs) show great potential for electrocatalysis due to their well-discrete metal active sites and inherently porous structures. Herein, Co is introduced into Ni along with organic ligand pyridine 2, 6-dicarboxylate through hydrothermal approach to form bimetallic electrocatalyst followed by its deposition on a highly porous nickel foam to evaluate both the oxygen and hydrogen evolution reactions (OER and HER). Electrochemical results show that the NiCo-H₂pdc catalyst only require overpotentials of 420 and 263 mV to achieve 30 mA cm⁻² of a current density in an alkaline electrolyte for O₂ and H₂ evolution, respectively, considerably less than the majority of documented electrocatalysts based on non-noble metals, and comparable with the standard Pt/C catalyst. Both OER and HER displayed the Tafel slope values of 89 and 73 mV/dec, also the double-layer capacitance values of 1.5 and 7.65 mF/cm². The exceptional bifunctional electrocatalytic performance of the developed NiCo-H₂pdc catalyst was also observed by a durability test of 24 h for both mechanisms. The innovation of the synergistic effect of dual metals opens up a new pathway for the strategic design of exceptionally efficient electrocatalysts based on MOFs.