Proton conducting 9P2O5–6TiO2–85SiO2 glass-filled Nafion® composite membranes

A series of proton conducting composite membranes based on Nafion® and 9P2O5–6TiO2–85SiO2 glass were prepared by the solution-cast method. Infrared (IR) spectroscopy and X-ray diffraction (XRD) spectrophotometer were employed for structural analysis of both 9P2O5–6TiO2–85SiO2- and 9P2O5–6TiO2–85SiO2-filled composite membranes. The effect of the filler on membrane properties was examined. As it offers not only a new proton conductive path associated with the increased proton carrier concentration, but also an increase in glassy regimes, it resulted in enhancement of proton conductivity, water uptake, and mechanical stability; however though, a reduction in methanol permeability. These properties were also affected by the membrane cleaning process, whereby the conductivity of the cleaned membrane with 3 wt.% gel content, 1.05 × 10−2 S/cm, was much higher than that of the non-cleaned at the same gel content, 0.5 × 10−2 S/cm.