In-Situ Study of Chemical Reactions and Crossover Processes in a Fuel Cell

Lin, Lu, and Shulamith Schlick

We performed experiments in an in-situ fuel cell (FC) inserted in the resonator of the electron spin resonance (ESR) spectrometer. 5,5-dimethylpyrroline N-oxide (DMPO) was selected as the spin trap. The in-situ FC was operated at 300 K with a membrane electrode assembly (MEA) based on the classic 3M membrane and Pt as catalyst, at closed circuit voltage (CCV) and open circuit voltage (OCV) conditions. The thickness of membrane was also considered as a factor that may influence the reaction mechanism. For the thinner membrane, DMPO/H and DMPO/OOH adducts were detected in all experiments (anode CCV and OCV, cathode CCV and OCV) and no adducts of the hydroxyl radical (HO·) were observed, suggesting strong gas crossover processes through the membrane. For the thicker membrane,1 a decreasing trend of gas crossover content was obtained. No carbon-centered radical (CCR) adducts were detected even after CCV FC operation of 4 h, suggesting that the classic 3M membrane is more resistant to degradation than the Nafion membrane.2-3

 

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  1. Haugen, G.; Barta, S.; Emery, M.; Hamrock, S.; Yandrasits, M. In Fuel Cell Chemistry and Operation, American Chemical Society: Washington, DC, 2010; pp 137-151.
  2. Danilczuk, M.; Coms, F. D.; Schlick, S. J. Phys. Chem. B  2009, 113(23), 8031-8042.
  3. Danilczuk, M.; Perkowski, A. J.; Schlick, S. Macromolecules, 2010, 43(7), 3352-3358.