Fabrication and gas sensing properties of hollow core-shell SnO2/α-Fe2O3 heterogeneous structures

One dimensional hierarchically hollow SnO2/alpha-Fe2O3 core-shell nanofibers were synthesized by using electrospun SnO2 hollow nanofibers as core followed by the hydrothermal growth and calcination of alpha-FeOOH nanorods on the outer surface of SnO2 nanofibers. The control experiments indicated that glacial acetic acid introduced in the hydrothermal solution could adjust the nucleation site and density of alpha-FeOOH nanorods as well as prevent the formation of urchin-like alpha-FeOOH byproduct. The growth process of alpha-FeOOH nanorods on SnO2 hollow nanofibers was also investigated. The hierarchical SnO2/alpha-Fe2O3 hollow nanofibers were then fabricated as gas sensors for the investigation of gas sensing applications. By comparison of sensing properties, the response values of the sensors fabricated with hierarchical SnO2/alpha-Fe2O3 core-shell nanofibers toward 100 ppm acetone and ethanol could reach to be 30.363 and 20.370, respectively, exhibiting much better performance than those using urchin-like alpha-Fe2O3 nanostructures and pure SnO2 nanofibers. Meanwhile, the sensors based on hierarchical SnO2/alpha-Fe2O3 nanofibers also had shorter response and recovery times than those of alpha-Fe2O3 nanostructures. The synergetic effect of the composite of alpha-Fe2O3 and SnO2 together with unique hollow core-shell architectures are main contribution for the enhanced gas sensing properties. (C) 2013 Elsevier B.V. All rights reserved.