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@INPROCEEDINGS{Jovanovic:1047388,
      author       = {Jovanovic, Sven and Rameker, Robert and Poc, Jean-Pierre
                      and Jodat, Eva and Karl, André and Eichel, Rüdiger-A. and
                      Granwehr, Josef},
      title        = {{A} novel perspective on accelerated degradation studies of
                      proton exchange membranes},
      reportid     = {FZJ-2025-04274},
      year         = {2025},
      abstract     = {Accelerated degradation studies are widely applied in
                      research on proton exchangemembranes (PEMs) for the
                      investigation of the origins and mechanisms of performance
                      lossfor electrolysis or fuel cell applications. In a
                      nutshell, it is reported in literature thatdegradation in
                      PEMs commonly occurs following Fenton-like reactions, where
                      in situ formedH2O2 reacts with transition metal cations to
                      produce radicals. These radicals then alter theionomer on a
                      chemical level by attacking particularly its polar side
                      chains, causing a loss offunctional moieties for proton
                      transport [1]. Fast degradation studies mimic and
                      promotethese conditions by subjecting PEMs to high
                      concentrations of H2O2 and Fe2+ cations atelevated
                      temperatures. However, these studies often exhibit
                      discrepancies when comparedto degradation occurring during
                      long-term operation [2].The presented work attempts to
                      elucidate these discrepancies by i)
                      addressinginconsistencies in accelerated degradation and
                      testing procedures, ii) studying thedependence of
                      degradation on PEM chemistry and structure and iii)
                      utilizing both NMRspectroscopy and SEM microscopy among
                      other techniques for a comprehensive picture.Hereby,
                      solid-state magic angle spinning (MAS) NMR spectroscopy
                      provides information onboth chemical and local structural
                      transformations of the PEM, while SEM offers
                      concreteinsights into structural changes on a microscopic
                      scale.The Fenton-like accelerated degradation experiments
                      were optimized for homogeneity andeffectiveness by
                      introducing the catalytic iron centers into the PEMs.
                      Additionally,interferences in the analytical techniques were
                      minimized by careful removal of excessreactants after
                      accelerated degradation. The combined analytical techniques
                      reveal thatchemical degradation in PEMs is significantly
                      less pronounced than suggested in literature,although
                      differences were observed depending on the type of PEM
                      material. Moreover,organic radicals that form during
                      Fenton-like reactions could not be detected by
                      EPRspectroscopy. However, all samples experienced
                      significant changes in the local structure,as indicated by
                      NMR relaxometry, and microscopic structure, as illustrated
                      by SEMtechniques. Thus, instead of chemical degradation, the
                      PEM may be affected on a structurallevel by mechanical
                      stress due to microscopic gas pockets and macroscopic
                      bubblesforming inside the gas impermeable material.[1] L.
                      Ghassemzadeh et al., J. Am. Chem. Soc. 135, 8181–8184
                      (2013).[2] J. Mališ et al., Int. J. Hydrogen Energy 41,
                      2177–2188 (2016).},
      month         = {Jul},
      date          = {2025-07-01},
      organization  = {European Electrolyser $\&$ Fuel Cell
                       Forum (EFCF), Lucerne (Switzerland), 1
                       Jul 2025 - 4 Jul 2025},
      subtyp        = {Panel discussion},
      cin          = {IET-1},
      cid          = {I:(DE-Juel1)IET-1-20110218},
      pnm          = {1231 - Electrochemistry for Hydrogen (POF4-123) / HITEC -
                      Helmholtz Interdisciplinary Doctoral Training in Energy and
                      Climate Research (HITEC) (HITEC-20170406)},
      pid          = {G:(DE-HGF)POF4-1231 / G:(DE-Juel1)HITEC-20170406},
      typ          = {PUB:(DE-HGF)24},
      url          = {https://juser.fz-juelich.de/record/1047388},
}