Abstract

In₂O₃ micro/nanotubes (MNTs) with different diameters are successfully synthesized by an effective and template-free coaxial electrospinning method. The diameters of the MNTs can be simply tailored by controlling the ratio of reactants. The HCHO sensing tests of as-prepared MNTs reveal that the samples possess high response value, fast response and recovery rate, and favorable selectivity. Moreover, compared with the large diameter (～1 μm or ～500 nm) In₂O₃ MNTs, the small diameter (～100 nm) In₂O₃ MNTs exhibit highly enhanced sensing properties. The gas sensing mechanism of In₂O₃ MNTs has been discussed in detail. The promising HCHO-sensing properties enable In₂O₃ MNTs to be a competitive candidate for detecting poisonous HCHO in practice. The experiment also indicates that the coaxial electrospinning is an environmental friendly and easy method for constructing tubular structure of metal oxides with different diameters for various applications.