Date of Award
Spring 5-15-2024
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Chemistry
First Advisor
Dr Ram Krishna Gupta
Second Advisor
Dr Khamis Siam
Third Advisor
Dr. Timothy Dawsey
Keywords
Electrochemical impedance spectroscopy, Linear sweep voltammetry, Sustainable energy systems, Turn over frequency, Urea electrolysis, Direct methanol fuel cells
Abstract
Water splitting, a critical milestone in the development of renewable energy, allowed the production of pure hydrogen (H2) and oxygen (O2). Iron oxide (Fe2O3), a transition metal oxide component in electrochemical water splitting for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), offered potential because of its accessibility, low cost, and environmental safety. 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 electrochemical properties of the Fe2O3-based electrocatalysts were evaluated towards HER and OER. It was observed that Fe2O3-AG outperformed Fe2O3-HT and Fe2O3-MW in most properties, demonstrating 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 mV, 235 mV, and 255 mV and overpotentials for OER of 222 mV, 288 mV, and 292 mV for the Fe2O3 AG, Fe2O3 HT, and Fe2O3 MW samples respectively, at a current density of 10 mA/cm2.
Additionally, the urea oxidation reaction (UOR) and methanol oxidation reaction (MOR) were investigated as complementary processes. Fe2O3-based electrocatalysts have been found to exhibit promising catalytic activity for both MOR and UOR due to their high surface area, abundant active sites, and favorable electron transfer properties. UOR results indicated overpotentials of 1.38 V, 1.45 V, and 1.47 V for the Fe2O3-AG, Fe2O3-HT, and Fe2O3-MW samples respectively, at a current density of 10 mA/cm2, showcasing the materials' efficacy in urea oxidation. Similarly, MOR results revealed overpotentials of 1.34V, 1.41 V, and 1.44 V for the Fe2O3-AG, Fe2O3-HT, and Fe2O3-MW samples respectively, at a current density of 10 mA/cm2, indicating their potential in methanol oxidation reactions. The freeze-drying synthesis process exhibited significant potential as a feasible method for the manufacture of Fe2O3-based electrocatalysts for various applications. The use of low-cost, ecologically acceptable components, as well as the scalable synthesis process, made this technology a strong option for future clean energy systems.
Recommended Citation
MALEY, NIHARIKA, "SYNTHESIS OF IRON OXIDE AS AN EFFICIENT ELECTROCATALYST FOR OVERALL WATER-SPLITTING, UREA OXIDATION REACTION AND METHANOL OXIDATION REACTION" (2024). Electronic Theses & Dissertations. 726.
https://digitalcommons.pittstate.edu/etd/726
