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| Home > Publications database > Dynamic and static degradation of perovskite oxide catalysts by electrochemical AFM |
| Poster (Other) | FZJ-2025-02721 |
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2025
Abstract: A fundamental understanding of degradation mechanisms under static and dynamic conditions is essential to develop catalysts for the oxygen evolution reaction (OER), the bottleneck in efficient electrochemical water splitting. Perovskite oxides are novel class of OER electrocatalysts [1-2], however, the differences in their degradation and stability in alkaline electrolyte are not yet fully understood. To address this, epitaxially grown La0.6Sr0.4CoO3 (LSCO), La0.6Sr0.4FeO3 (LSFO) and La0.6Sr0.4MnO3 (LSMO) were compared by employing electrochemical atomic force microscopy (AFM) during cyclic voltammetry (CV) and chronoamperometry (CA).Electrochemical AFM results, mapping the topography and friction force of materials during the first CV showed distinctly different and irreversible degradation paths for perovskites. Continuous topography and friction force measurements over prolonged cycling, as well as post-catalysis analyses, further supported the observed dynamic degradation mechanisms, specifically bulk degradation in LSCO and LSMO, and surface passivation in LSFO. Consequently, the Co-based perovskite exhibited reduced stability and activity loss, whereas the Fe-based perovskite demonstrated improved stability. A comparison with steady-state OER conditions showed that electrochemical AFM during CA detected a short delay of morphology and friction force changes relative to the start of electrochemistry. The results elucidate how electrochemical AFM can differentiate degradation mechanisms under dynamic and static conditions in alkaline environments as well as between transition metals in perovskite oxides. Thereby, the conclusions contribute significantly to the understanding of perovskite degradation at the solid-liquid interface. References:[1] Weber, M., Gunkel, F. et al. J. Am. Chem. Soc. 2022, 144, 17966-17979 [2] Akbashew, A. et al., Energy Environ. Sci., 2023, 16, 513-522
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