Tailored Flower-Like Ni-Fe-MOF-Derived oxide Composites: Highly active and durable electrocatalysts for overall water splitting

The need for a carbon–neutral society necessitates sustainable hydrogen production by water electrolysis. Water electrolysis is an energy-demanding process, maintaining efficient and environmentally friendly hydrogen production requires significant energy input. The process always requires a catalyst to reduce energy consumption for cost-effectiveness. In this pursuit, a bifunctional electrocatalyst (Fe₃O₄/NiO-C) with enhanced catalytic performance was synthesized using Ni-Fe-MOF as a precursor. Compared to Ni-Fe-MOF, Fe₃O₄/NiO-C exhibited remarkable improvement in electrochemical performance, fast reaction kinetics, and long-term durability. It achieved an ultrahigh current density of 500 mAcm⁻² at an overpotential of 280 mV for the oxygen evolution reaction (OER) and 50 mAcm⁻² at 182.5 mV for the hydrogen evolution reaction (HER) with a Tafel slope of 59.0 mV/dec and 53 mV/dec, respectively. Moreover, it showed prolonged electrochemical durability with a high-performance retention of 86 % for OER and 93 % for HER after (24 hrs). This exceptional performance of Fe₃O₄/NiO-C is attributed to its unique composition, interfacial interaction, high surface area, and porosity. This study underscores the importance of MOF-derived transition metal oxides as efficient, highly active, and stable electrocatalysts for overall water-splitting.