Theoretical Investigation of the H2O2-Induced Degradation Mechanism of Hydrated Nafion Membrane via Ether-Linkage Dissociation

Takao Tsuneda, Raman K. Singh, Akihiro Iiyama, Kenji Miyatake

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

A H2O2-induced degradation mechanism is presented for the hydrated Nafion membrane proceeding through the dissociation of the ether linkages of the side chains. Although the durability of proton-exchange membrane fuel cells clearly depends on the degradation rate of the membrane, typically Nafion, the degradation mechanism still has not been resolved. It has often been assumed that the principal mode of degradation involves OH radicals; in contrast, we show here that a H2O2-induced degradation mechanism is more likely. On the basis of state-of-the-art theoretical calculations and detailed comparison with experimental results, we present such a mechanism for the hydrated Nafion membrane, proceeding through the dissociation of the ether linkage of the side chains, with a relatively low activation energy. In this mechanism, (H2O)HO3S-CF2-CF2-O-O-H (is the hydration number) is obtained as a key degradation fragment. Possible subsequent decomposition-reaction mechanisms are also elucidated for this fragment. The calculated vibrational spectra for the intermediates and products proposed in these mechanisms were found to be consistent with the experimental IR spectra. Further consideration of this H2O2-mediated degradation mechanism could greatly facilitate the search for ways to combat membrane degradation.

Original languageEnglish
Pages (from-to)4053-4064
Number of pages12
JournalACS Omega
Volume2
Issue number7
DOIs
Publication statusPublished - 2017 Jul 31
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)

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