Enhanced ethanol sensing properties of TiO2 nanotube sensors

TiO2 nanotube arrays were prepared for use as gas sensors by anodizing Ti thin foils. Transmission electron microscopy revealed a tube diameter and length ranging from 70 to 120 nm and 300 to 400 nm, respectively. The TiO2 nanotube array sensors showed responses of 68,000 and 1,380,000% to 300 and 1000 ppm C2H5OH at 250 °C, respectively. These values are far superior to the responses obtained by most oxide one-dimensional nanostructures reported in the literature. In addition, the ethanol sensing mechanism of the TiO2 nanotube array sensors is discussed.