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

SnO2/α-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 °C for 2 h, for the improvement of one-dimensional α-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 (xSnO2/0.5(1 − x)α-Fe2O3) composite nanotubes. The grain size of α-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.