Facile synthesis of α-Fe2O3@SnO2 core–shell heterostructure nanotubes for high performance gas sensors

Abstract A facile hydrothermal method was employed to synthesize porous α-Fe 2 O 3 @SnO 2 heterostructure nanotubes. The morphologies and structures of the as-prepared samples were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and N 2 adsorption–desorption techniques. The hollow α-Fe 2 O 3 nanotubes with outer diameters of about 90 nm were uniformly coated by a 10 nm thick layer of SnO 2 nanoparticles, demonstrating apparent heterostructures. The α-Fe 2 O 3 @SnO 2 heterostructure nanotubes were applied to construct gas-sensor devices which exhibited high sensitivity, fast response–recovery, good selectivity and excellent repeatability to acetone. Because of the porous structure and large specific surface area, the heterogeneous core–shell nanocomposites show a markedly enhanced gas sensing performance in comparison with the initial α-Fe 2 O 3 nanotubes and the pure SnO 2 nanoparticles. For example, the sensitivity of the α-Fe 2 O 3 @SnO 2 composites to 100 ppm acetone can reach as high as 33.4 at the optimum operating temperature of 300 °C, which was about twice of the value for pure α-Fe 2 O 3 nanotubes and even up to 5-fold higher than that of pure SnO 2 nanoparticles.

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