Tuning Synthesis Parameters and Electrochemical Activity of Spinel-Structured High-Entropy (Cr, Mn, Fe, Ni, Sn) Oxides for Alkaline Water Electrolysis
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2025-07-11 |
| Journal | ECS Meeting Abstracts |
| Authors | BegĂźm Yarar Kaplan, Pietro Mattana, Enrico Negro, Gioele Pagot, Keti VezzĂš |
Abstract
Section titled âAbstractâThe electrochemical splitting of water for the production of âgreen hydrogenâ holds great promise; however, the efficiency of the corresponding electrochemical reactions is crucial for its practical implementation. One of the main bottlenecks is the development of inexpensive and highly active electrocatalysts (ECs) for the oxygen evolution reaction (OER). Indeed, the latter process is typically slower than the hydrogen evolution reaction (HER), thus causing larger overpotentials. Spinel-structured transition metal (TM) oxides have emerged as promising and sustainable alternatives to ECs based on platinum-group metals (PGMs) for devices operating in an alkaline environment. Spinel-structured high-entropy oxides (SHEOs) with multiple TM-cation sites are ideal to design octahedral redox-active centers that can improve the EC activity [1,2]. The presence of surface oxygen vacancies contributes to achieve a promising electrochemical performance in the OER. In this work new (Cr, Mn, Fe, Sn, Ni) SHEOs are proposed, especially targeted to enhance the OER activity in the alkaline environment. The effect of calcination conditions on the electrochemical performance and surface-active sites of (Cr, Mn, Fe, Sn, Ni) SHEOs are investigated towards the alkaline OER. Changes in the chemical structure of SHEOs during single/multi-step calcinations at different temperatures are examined by XRD, ICP-AES, and NAP-XPS. The morphology is probed by SEM and TEM; the porosimetric features are assessed via nitrogen physisorption studies. The OER kinetics and mechanism are investigated by cyclic voltammetry with the thin-film rotating ring-disk electrode (CV-TF-RRDE). Particular attention is dedicated to elucidating the role of Sn in the modulation of: (i) the physicochemical features; and (ii) the electrochemical performance in the OER carried out in the alkaline environment. References [1] VezzĂš, K., Triolo, C., Moulaee, K., Pagot, G., Ponti, A., Pinna, N., Neri, G., Santangelo, S. and Di Noto, V., Small, 2408319, 2024. [2] Triolo, C., Moulaee, K., Ponti, A., Pagot, G., Di Noto, V., Pinna, N., Neri, G. and Santangelo, S., Advanced Functional Materials, 34(6), 2306375, 2024. Acknowledgements This work has been supported under: (a) the National Recovery and Resilience Plan (NRRP), funded by the European Union - NextGenerationEU [Award Number: CNMS named MOST, Concession Decree No. 1033 of June 17, 2022, adopted by the Italian Ministry of University and Research, Spoke 14 âHydrogen and New Fuelsâ ]; and (b) the project DURALYS funded by the the Italian Ministry of Foreign Affairs and International Cooperation (MAECI).