Tailored Flower-Like Ni-Fe-MOF-Derived Oxide Composites: Highly Active and Durable Electrocatalysts for Overall Water Splitting

Abstract

To achieve a carbon-neutral future, it is essential to develop sustainable methods for hydrogen production by water electrolysis. Efficient and eco-friendly hydrogen production through electrolysis demands significant energy input. This high energy requirement necessitates the use of catalysts to reduce energy consumption making electrolysis process to be economically viable. In this pursuit, we synthesized a bifunctional electrocatalyst (Fe3O4/NiO-C) with improved catalytic performance using Ni-Fe-MOF as the precursor material. The Fe3O4/NiO C catalyst demonstrated a substantial enhancement in electrochemical performance, faster reaction kinetics, and long-term durability compared to pristine Ni-Fe-MOF. It achieved an exceptionally high current density of 500 mA cm-2 at an overpotential of 280 mV for the oxygen evolution reaction (OER) and 50 mA cm-2 at 182.5 mV for the hydrogen evolution reaction (HER), with Tafel slopes of 59.0 mV/dec and 53 mV/dec, respectively. Additionally, it showed extended electrochemical stability, maintaining 86% performance for OER and 93% for HER after 24 hours of chronoamperometry test. The outstanding performance of Fe3O4/NiO-C is due to its unique composition, interfacial interactions, and its high surface area and porosity. This research emphasizes the significance of MOF-derived transition metal oxides as highly efficient, active, and stable bifunctional electrocatalysts for water-splitting.