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| Home > Publications database > Degradation studies on PEM materials by MAS and PFG-NMR |
| Home > Publications database > Degradation studies on PEM materials by MAS and PFG-NMR |
| Poster (Invited) | FZJ-2026-01374 |
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2025
Abstract: PEM electrolysis is considered a promising technique to produce green hydrogen at high purity. But the high cost of MEA components and the hazardous nature of PFAS materials are forcing the industry to use PEM materials in a resource-conscious way. As dissolving and recasting of PEM materials requires high resource consumption, ways to reuse PEM materials without dissolving will be relevant for the industry.We have developed an NMR-based routine which combines 19F MAS-NMR and low-field 1H NMR methods to test the invasiveness of these separation methods on the structure of the membrane.The high-field 19F MAS-NMR methods provide a detailed insight into changes in the molecular and spatial structure of the material. On the spectra we see a significant alteration of the shape of the SCF2 and OCF2 signal induced by the separation step. By integrating the signals, a decrease in the intensity of the side chain signals can be determined which suggests degradation especially related to the ionomer side chain.Alteration of the spatial structure, on the other hand, is revealed by a significant decrease in T1 relaxation time. A local rearrangement of the spatial ionomer structure induced by the ultrasound used during the separation step is suggested.The low-field 1H NMR methods are considered as suitable techniques which can be implemented in industrial quality management due to easy operation of the spectrometer. Here, an increase of the diffusion coefficient after the separation process was observed. In addition, two slow-exchanging domains of water can be distinguished. While increased diffusion is observed due to the spatial change in the membrane structure, the ion exchange capacity and thus the selectivity of the membrane decreases.To conclude, 19F MAS-NMR allows precise detection of changes in PEM chemistry and structure, while 1H NMR provides correlated findings and methods for fast and reproducible quality control. In this study, the applied separation technique leads to a non-negligible chemical and spatial degradation.
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