Enhancing Iron Oxide Electrocatalysis for Efficient Overall Water Splitting: A Study of Tailored Synthesis for Advanced Energy Generation and Storage

Water splitting, a critical milestone in the development of renewable energy, allows the production of pure hydrogen and oxygen. Iron oxide (Fe₂O₃), a fundamental component in electrochemical water splitting for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), offers potential because of its accessibility, low cost, and environmental safety. Herein, to analyze the impact of the methodology on its properties, Fe₂O₃ was produced in three different ways: freeze-drying (aerogel) (Fe₂O₃-AG), hydrothermal (Fe₂O₃-HT), and microwave (Fe₂O₃-MW). The Fe₂O₃-AG outperformed Fe₂O₃-HT and Fe₂O₃-MW in most properties which showed improved current and overall water-splitting efficiency. The resulting materials demonstrated good electrocatalytic performance for both HER and OER in alkaline media, with overpotentials for HER of 204, 235, and 255 mV and overpotentials for OER of 222, 288, and 292 mV for the Fe₂O₃-AG, Fe₂O₃-HT, and Fe₂O₃-MW samples, respectively, at a current density of 10 mA/cm². The freeze-drying synthesis process has significant potential as a feasible method for the manufacture of Fe₂O₃-based electrocatalysts for water-splitting applications. This study provides important insights into the influence of electrocatalytic and energy storage properties of Fe₂O₃ based on the use of different methodologies, that is, hydrothermal, microwave-assisted, and freeze-drying. Through that, a more assertive analysis can be made concerning changes in morphology, conductivity, exposure of active area, and electrochemical stability which are crucial for the overall performance, hence providing valuable information and considerations for possible large-scale applications for energy generation and energy storage.