Enhanced ethanol sensing properties of multiple networked Au-doped In2O3 nanotube sensors

In2O3 nanotubes were synthesized as gas sensors using TeO2 nanowires as a template. Scanning and transmission electron microscopy revealed the tubes to have diameters of a few hundred nanometers, wall thickness of ∼25 nm and lengths up to a few millimeters. Multiple networked Au-doped In2O3 nanotube sensors showed responses of 187–1219% to 50–250 ppm C2H5OH at 300 °C. These responses are far superior to those obtained by undoped In2O3 nanotubes and stronger than those obtained by pure In2O3 nanowires at 370 °C. In addition, the ethanol sensing mechanism of the Au-doped In2O3 nanotube sensors is discussed.

► Au-doped In2O3 nanotubes were synthesized using TeO2 nanowires as a template.
► The nanotube sensors showed responses of 187–1219% to 50–250 ppm C2H5OH at 300 °C.
► These response values are far superior to those obtained by undoped In2O3 nanotubes.
► These response values are higher than those obtained by pure In2O3 nanowires at 370 °C.
► The ethanol sensing mechanism of the Au-doped In2O3 nanotube sensors is discussed.