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The Major Role of Hydrogen Atoms in the Fragmentation of Ionomeric Membranes Used in Fuel Cells Shulamith Schlick, University of Detroit Mercy, DMR 0964827.
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The Major Role of Hydrogen Atoms in the Fragmentation of Ionomeric Membranes Used in Fuel Cells Shulamith Schlick, University of Detroit Mercy, DMR 0964827 This step is expected to cause main chain and side chain scission, and to generate RF–CF2• radicals that can react with H2O2, H2O, and H2 to produce both –COOH and RCF2H groups and to lead to the formation of the C-H and C=O groups detected in this study. RF–CF2• + H2O2 → RF–CF2H + HOO• (1) RF–CF2• + H2O2 → RF–CF2OH + HO• (2) RF–CF2OH + H2O → RF–CO2H + 2HF (3) RF–CF2• + H2 → RF–CF2H + H• (4) In-depth profiling of the degradation for Nafion membranes led to 2D FTIR spectral-spatial maps, which indicated that C-H and C=O groups were generated during degradation, see Figure. The two degradation bands appeared at the same depths from the cathode, 82 and 22 m, suggesting their generation by a common mechanism. This result is rationalized by a very important first reaction: Abstraction of a fluorine atom from the main chain and side chain by hydrogen atoms, H•. Danilczuk, M.; Lancucki, L.; Schlick, S.; Hamrock, S.J.; Haugen, G.M. ACS Macro Lett.2012, 1, 280-285.
Broader Impact ActivitiesShulamith Schlick, University of Detroit Mercy, DMR 0964827 • The Group: Visiting graduate student L. Lancucki (Jagiellonian University, Krakow, Poland), postdoctorals M. Danilczuk, and M. Spulber. • Translational Research. Our collaborationwith scientists and engineers from 3M, Ford Laboratories, and the Electrochemical Energy Research Lab of General Motors on the degradation and stabilization of membranes used in fuel cells is an example of the connectivity between fundamental research and applications: The kinetic approach developed by our group for ranking membrane stability has encouraged efforts on the synthesis of more stable membranes. • International Collaborations. PI Schlick has continued the collaboration with K. Kruczala (Krakow), and with the group of Bogdan Simionescu at the Petru Poni Institute, Yassy, Romania. • New Collaboration. Recently we started a collaboration with Professor Frederick Villamena of Ohio State University, and published our work entitled “Guest Inclusion in Cucurbiturils Studied by ESR and DFT: The Case of Nitroxide Radicals and Spin Adducts of DMPO and MNP” in J. Phys. Chem. A(doi.org/10.1021/jp303536m) • PI Schlick was part of DOE7, a group of scientists and engineers from 3M Company in St. Paul, MN, and five professors at US universities. In annual meetings and reports, teleconferences, and quarterly reports, the PI’s fundamental research on the degradation of fuel cell membranes has contributed to the recent “go” DOE decision (funding until 31 March 2011). Understanding the degradation mechanism is an inspiration for makers of the membranes. • The collaboration with S. Hamrock and his colleagues at 3M continues. Presently we are considering methods for transforming the fluorinated precursor of the 3M membranes into anion exchange membranes (AEMs), which are expected to have some advantages compared to proton exchange membranes (PEMs).