Synthesis of pristine In2O3/ZnO–In2O3 composited nanotubes and investigate the enhancement of their acetone sensing properties

Pristine In2O3 and ZnO–In2O3 composited nanotubes were synthesized by the electrospinning technic and followed by calcination. The formation of ZnO–In2O3 n–n heterojunctions was found to be highly sensitive to acetone gas. X-ray powder diffraction (XRD), Scanning electron microscope (SEM) and energy dispersive X-ray spectrometry (EDS) were respectively used to characterize surface crystallinity and morphology. The possible mechanism of nanotubes formation was also investigated. Gas sensors were made based on the as-synthesized materials to investigate their gas sensing properties. Compare with the pristine In2O3 nanotubes, ZnO–In2O3 composite nanotubes show the obviously improved of acetone sensitivity. The sensitivity of ZnO–In2O3 composite nanotubes is about 43.2, which is about triple times larger than that of the pristine In2O3 nanotubes to 60 ppm acetone at 280 °C. The response and recovery times of ZnO–In2O3 nanotubes to 60 ppm acetone are about 5 and 25 s. In addition, ZnO–In2O3 composite nanotubes sensor also possesses a good selectivity to acetone.