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

A facile hydrothermal method was employed to synthesize porous alpha-Fe2O3@SnO2 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 alpha-Fe2O3 nanotubes with outer diameters of about 90 nm were uniformly coated by a 10 nm thick layer of SnO2 nanoparticles, demonstrating apparent heterostructures. The alpha-Fe2O3@SnO2 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 alpha-Fe2O3 nanotubes and the pure SnO2 nanoparticles. For example, the sensitivity of the alpha-Fe2O3@SnO2 composites to 100 ppm acetone can reach as high as 33.4 at the optimum operating temperature of 300 degrees C, which was about twice of the value for pure alpha-Fe2O3 nanotubes and even up to 5-fold higher than that of pure SnO2 nanoparticles. (C) 2015 Elsevier B.V. All rights reserved.