Effects of SnO2 additives on nanostructure and gas-sensing properties of α-Fe2O3 nanotubes

SnO2/alpha-Fe2O3 (SFO) nanotubes with different Sn/Fe molar ratios have been synthesized by a facile single-capillary electrospinning route, followed by heat treatment at 500 degrees C for 2 h, for the improvement of one-dimensional alpha-Fe2O3 based sensing materials achieving high performance. Scanning electron microscopy, transmission electron microscopy, and X-ray diffraction results indicated that the amount of SnO2 additives largely influenced the phases and structures of SFO-x (xSnO(2)/0.5(1-x)alpha-Fe2O3) composite nanotubes. The grain size of alpha-Fe2O3 gradually decreased with the increase of tin components. Especially in the SFO-0.33 nanotubes, a thorn-like hierarchical structure was formed. The surface segregation and phase separation effects are suggested as the growth mechanism. And these special architectures expectedly made the sensors, based on SFO-x (0.025 <= x <= 0.2) nanotubes, significantly enhancing sensitivity and selectivity in ethanol detection. Our research may be meaningful for extending our view of the electrospun SFO composites. (C) 2014 Elsevier B.V. All rights reserved.