One-dimensional proton conductor under high vapor pressure condition employing titanate nanotube

Metal oxides with the nano-structure, such as nano-porous, -sheet, -particle, and -tube, have been attracted for the functional materials on the future technology. Especially, one-dimensional (1D) metal oxide nanotubes are emerging as potentially useful materials. In this paper, we prepared the 1D proton conductor under high vapor pressure condition employing titanate (H2Ti3O7) nanotube (TNT). This metal oxide nanotube showed the proton conductivity of 5 × 10−4 S cm−1 at intermediate temperature (⩽160 °C), fully saturated humidification (relative humidity of 100%), and high vapor pressure (6 atm) conditions. This conduction behavior in metal oxide nanotube is controlled by the liquid phase mediated charge transport (liquid-like mechanism). The proton conductor of 1D may have a potential not only for the fuel cell electrolytes operated at intermediate temperature conditions but also for various electrochemical devices. Furthermore, 1D proton conductor, such as TNT, might be used as the basic proton conductor to discuss the proton conductive mechanism.