Preparation of Nafion 117™-SnO2 composite membranes using an ion-exchange method

Nafion 117 (TM)-SnO2 composite membranes were prepared by in-situ particle formation using an ion-exchange method. SnO2 was incorporated into Nafion 117 (TM) membranes by ion-exchange in solutions of SnCl2 center dot 2 H2O in methanol, followed by oxidation to SnO2 in air. By adjustment of the concentration of SnCl2 center dot 2 H2O used in the ion-exchange step, compositions ranging from 2 to 8 wt.% SnO2 with SnO2 homogeneously distributed as nanoparticles were obtained. The prepared nanocomposite membranes were characterized by powder XRD, Sn-119 MAS NMR spectroscopy, electrochemical impedance spectroscopy, water uptake, tensile stress-strain measurements and thermogravimetric analysis. A SnO2 content around 4 wt.% gave a significant increase in membrane stiffness without losses in conductivity. (c) 2011 Elsevier B.V. All rights reserved.