Nafion-bifunctional silica composite proton conductive membranesElectronic supplementary information (ESI) available: SEM images of the surface of a NBS composite membrane (a) and a Nafion 117 membrane (b). Inset: A NBS composite membrane at high magnification. See http://www.rsc.org/suppdata/jm/b1/b107498a/
Wang, Huanting; Holmberg, Brett A.; Huang, Limin; Wang, Zhengbao; Mitra, Anupum; Norbeck, Joseph M.; Yan, Yushan; Wang Huanting; College of Engineering - Center for Environmental Research and Technology (CE-CERT), and Department of Chemical and Environmental Engineering, University of California; Holmberg Brett A.; College of Engineering - Center for Environmental Research and Technology (CE-CERT), and Department of Chemical and Environmental Engineering, University of California; Huang Limin; College of Engineering - Center for Environmental Research and Technology (CE-CERT), and Department of Chemical and Environmental Engineering, University of California; Wang Zhengbao; College of Engineering - Center for Environmental Research and Technology (CE-CERT), and Department of Chemical and Environmental Engineering, University of California; Mitra Anupum; College of Engineering - Center for Environmental Research and Technology (CE-CERT), and Department of Chemical and Environmental Engineering, University of California; Norbeck Joseph M.; College of Engineering - Center for Environmental Research and Technology (CE-CERT), and Department of Chemical and Environmental Engineering, University of California; Yan Yushan; College of Engineering - Center for Environmental Research and Technology (CE-CERT), and Department of Chemical and Environmental Engineering, University of California
Журнал:
Journal of Materials Chemistry
Дата:
2002
Аннотация:
Solâ gel derived sulfonated phenethylsilica with hydrophilic â Si-OH and proton conductive â SO3H functional groups was used as a bifunctional additive to improve the proton conductivity and water uptake characteristics of Nafion. Nafion-bifunctional silica (NBS) composite membranes were prepared by casting Nafionâ ethanol solutions mixed with sulfonated phenethylsilica sol. The ion exchange capability of NBS composite membranes increases linearly with the amount of bifunctional silica incorporated, and is about 1.9 à 10<sup>â 3</sup> mol SO3H g<sup>â 1</sup> for NBS with 7.5 wt% silica. Liquid water uptake measurements showed that NBS composite membranes have higher water uptake (g H2O g<sup>â 1</sup> composite membrane) than bare recast Nafion while the degree of hydration (i.e., nH2Oâ SO3H) remains fairly constant. The NBS composite membranes showed improved proton conductivity when compared with bare recast Nafion and Nafion 117 membranes at 80 °C and over a range of relative humidity.
137.0Кб