Electrospun In2O3/α-Fe2O3 heterostructure nanotubes for highly sensitive gas sensor applications

Abstract

In₂O₃/α-Fe₂O₃ (IFO) heterostructure nanotubes, with cubic-In₂O₃ nanocrystals randomly distributed on the surface of α-Fe₂O₃ nanotube-based backbones, were successfully prepared through a facile single-capillary electrospinning method. The morphologies of the resulting electrospun products were characterized by scanning electron microscopy and transmission electron microscopy. The crystal structures and components were determined by X-ray diffraction and energy-dispersive X-ray spectra, respectively. The results show that the morphology and structure of the products could be tailored by changing the content of indium nitrate in the precursor solutions and the calcination temperatures. Moreover, the IFO-0.1 (In/Fe = 1 : 9, molar ratio) nanotubes based sensor shows a high sensitivity to ethanol with a fast response/recovery time, and the performance is stable at a low operating temperature, which gives a potential application in ethanol gas sensors. A possible gas sensing mechanism based on the role of In₂O₃ in such a heterostructure is also discussed in detail.