Micro- and nano-scale hollow TiO2 fibers by coaxial electrospinning: Preparation and gas sensing

We report the preparation of micro- and nano-scale hollow TiO₂ fibers using a coaxial electrospinning technique and their gas sensing properties in terms of CO. The diameter of hollow TiO₂ fibers can be controlled from 200 nm to several micrometers by changing the viscosity of electrospinning solutions. Lower viscosities produce slim hollow nanofibers. In contrast, fat hollow microfibers are obtained in the case of higher viscosities. A simple mathematical expression is presented to predict the change in diameter of hollow TiO₂ fibers as a function of viscosity. The successful control over the diameter of hollow TiO₂ fibers is expected to bring extensive applications. To test a potential use of hollow TiO₂ fibers in chemical gas sensors, their sensing properties to CO are investigated at room temperature.