Facile Synthesis of Co-MOF Nanoflakes as an Efficient and Durable Electrocatalyst for HER and OER Applications in Alkaline Medium

Abstract Water splitting is essential for storing sustainable energy and producing hydrogen in an environmentally friendly manner. In recent years, metal–organic frameworks (MOFs) have gained recognition for their versatility, characterized by their large surface areas, adjustable porosity, and ability to undergo easy composition modification. These properties make MOFs and their derivatives promising candidates for catalyzing water electrolysis. The MOF studied here contains cobalt as its metal center and a Schiff base linker derived from 2-aminobenzoic acid and terephthalaldehyde. The synthesized powder underwent thorough analysis using techniques such as Fourier-transform infrared spectroscopy (FT-IR), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) surface area measurement, and thermal analysis. The efficiency of the Co-MOF in water splitting was assessed, demonstrating significant catalytic performance comparable to other modified MOF catalysts reported in literature. Specifically, the hydrogen evolution electrode achieved a current density of 10 mA/cm² with an overpotential of 37 mV (vs. Ag/AgCl) and a Tafel slope of approximately 100 mV dec⁻¹. For oxygen evolution at 100 mA/cm², an overpotential of 803 mV (vs. Ag/AgCl) and a Tafel slope of 226.6 mV dec⁻¹ were observed.