Enhanced formaldehyde-sensing properties of mixed Fe2O3–In2O3 nanotubes

Pure In2O3 and mixed Fe2O3–In2O3 nanotubes were prepared by simple electrospinning and subsequent calcination. The as-prepared nanotubes were characterized by scanning electron microscopy, powder X-ray diffraction, and energy-dispersive X-ray spectrometry. Gas sensors were fabricated to investigate the gas-sensing properties of In2O3 and Fe2O3–In2O3 nanotubes. Compared to pure In2O3, Fe2O3–In2O3 nanotubes exhibited better gas-sensing properties for formaldehyde at 250 °C. The response of the Fe2O3–In2O3 nanotube gas sensor to 100 ppm formaldehyde was approximately 33, which is approximately double the response of the pure In2O3 nanotube gas sensor. In both cases the response time was ~5 s and the recovery time was ~25 s.