In this report we attempt to synthesize materials resistant to dehydration by exploiting the interaction of sulfonate groups with the hydrophilic surfaces of the inner pore walls of mesoporous titanium oxides to form channels for proton conduction. Thus, six mesoporous titanium oxide composites of naphthalene sulfonate formaldehyde (NSF) were synthesised, fully characterised and formed into pellets for potentiostatic impedance measurements. The most promising sample, a NSF composite of mesoporous TiO2 (mTiO2), displays a proton conductivity of 1.837 mS cm-1 at 100 C surpassing that of a pellet of Nafion 117 constructed as a reference under the same conditions (1.143 mS cm-1). This material also has greater conductivity than pure hydrated NSF (0.122 mS cm-1), confirming a synergistic interaction between the NSF and the oxide mesostructure in the proton conductivity mechanism. Both 1H and 13C solid state NMR studies of the NSF material and the mTiO2-NSF composites demonstrate that the oligomeric nature of the NSF is preserved while in contact with the mTiO2 surface, thus facilitating conductivity.
- Impedance spectroscopy
- Mesoporous materials
- Naphthalene sulfonate formaldehyde
- Proton conductivity