From a broad perspective, this research focuses on the production of green hydrogen using renewable energy sources. According to the International Energy Agency’s Global Hydrogen Review 2025 [1], less than 1% of global hydrogen production currently relies on electricity-based technologies. This limited adoption is primarily due to three factors: the relative immaturity of the technology, regulatory constraints, and the significantly higher production costs of green hydrogen compared to hydrogen derived from coal or natural gas. The conventional approach to green hydrogen production involves water electrolysis, in which hydrogen is generated at the cathode and oxygen at the anode through the oxygen evolution reaction (OER). However, extensive literature and experimental evidence [2] indicate that the OER is kinetically sluggish, resulting in substantial energy losses due to high overpotentials.
To reduce the overall energy demand of water electrolysis, hybrid water-splitting systems have been proposed [3]. These systems replace the anodic OER with alternative oxidation reactions (AORs), lowering the required cell voltage, as well as enabling the simultaneous production of value-added chemicals at the anode.
The present fellowship research focuses on the development and electrochemical evaluation of ternary CoNiFeOx catalysts for the anodic oxidation of organic compounds, particularly alcohols, under alkaline conditions to yield value-added products. From a catalyst design perspective, CoNiFeOx materials are closely related to Ni(OOH) electrodes, which were among the earliest materials identified as highly efficient water oxidation catalysts in alkaline electrolysis [4]. Subsequent studies have demonstrated that Ni-based oxide and hydroxide electrodes also exhibit high catalytic activity and selectivity for the electrochemical oxidation of alcohols to carboxylic acids [5–6], as well as the oxidation of amines to nitriles [6–7].
In recent years, a wide range of mixed metal oxide electrocatalysts containing transition metals such as Co, Ni, Mn, Fe, Cu, and Zn have been investigated for the OER [8]. Notably, recent studies conducted at the Leibniz Institute for Catalysis (Rostock) have demonstrated that CoNiFe oxide electrocatalysts outperform commercially available Co₂NiOx and other benchmark catalysts in OER [9]. Preliminary results obtained during the initial phase of this fellowship further suggest that these mixed metal oxide catalysts are also effective for the electrochemical oxidation of alcohols [9].
Based on existing knowledge of Ni-based oxide and hydroxide electrodes, as well as recent advances in mixed-metal oxide electrocatalysts for the OER, this project aims to explore the potential of CoNiFeOx as a versatile, earth-abundant catalytic platform for alternative oxidation reactions. The overarching goal is to enable the sustainable electrosynthesis of value-added chemicals from renewable feedstocks, such as biomass-derived alcohols, including ethanol and ethylene glycol, and sugars, while simultaneously integrating these reactions into hybrid water-splitting systems to reduce the energy consumption of hydrogen-producing electrolysis cells
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Literature:
[1] IEA (2025), Global Hydrogen Review 2025, IEA, Paris https://www.iea.org/reports/global-hydrogen-review-2025, License: CC BY 4.0
[2] Zhang, K., & Zou, R. (2021). Advanced transition metal‐based OER electrocatalysts: current status, opportunities, and challenges. Small , 17 (37), 2100129.
[3] Fan, L., Wang, D., Ma, K., Zhou, CA, & Yue, H. (2024). Recent advances in hydrogen production from hybrid water electrolysis through alternative oxidation reactions. ChemCatChem , 16 (5), e202301332.
[4] Weininger, JL, & Breiter, MW (1964). Hydrogen evolution and surface oxidation of nickel electrodes in alkaline solution. Journal of The Electrochemical Society, 111(6), 707. DOI: 10.1149/1.2426216
[5] Kaulen, J., & Schäfer, HJ (1982). Oxidation of alcohols by electrochemically regenerated nickel oxide hydroxide. Selective oxidation of hydroxysteroids. Tetrahedron, 38(22), 3299-3308. DOI: 10.1016/0040-4020(82)80110-5
[6] Fleischmann, M., Korinek, K., & Pletcher, D. (1972). The kinetics and mechanism of the oxidation of amines and alcohols at oxide-covered nickel, silver, copper, and cobalt electrodes. Journal of the Chemical Society, Perkin Transactions 2, (10), 1396-1403. DOI: 10.1039/P29720001396
[7] Feldhues, U., & Schäfer, H. (1982). Oxidation of primary aliphatic amines to nitriles at the nickel hydroxide electrode. Synthesis, 1982(02), 145-146. DOI: 10.1055/s-1982-29721
[8] Vazhayil, A., Vazhayal, L., Thomas, J., & Thomas, N. (2021). A comprehensive review on the recent developments in transition metal-based electrocatalysts for oxygen evolution reaction. Applied surface science advances, 6, 100184. DOI: 10.1016/j.apsadv.2021.100184
[9] Pham, TM, Plevova, M., Bartling, S., Rockstroh, N., Springer, A., Slabon, A., … & Francke, R. (2024). Oxygen-deficient annealing boosts performance of CoNiFe oxide electrocatalyst in oxygen evolution reaction. Journal of Catalysis, 438, 115675. DOI: 10.1016/j.jcat.2024.115675