Excellent acetone sensing properties of Sm-doped α-Fe₂O₃

Highlights: • We have studied the effect on the gas-sensing properties of α-Fe₂O₃ nanotubes by doping Sm. • The Sm-doped α-Fe₂O₃ nanotubes sensors show ultrahigh sensitivity to acetone. • The lowest detection limit is 500 ppb. - Abstract: Pure and 3 wt% Sm-doped α-Fe₂O₃ nanotubes are prepared via a typical electrospinning technology and calcination procedure. The characteristic and morphology of the synthesized nanotubes are investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). Compared with pure α-Fe₂O₃ nanotubes, 3 wt% Sm-doped α-Fe₂O₃ nanotubes display enhanced gas-sensing properties. The response of 3 wt% Sm-doped α-Fe₂O₃ nanotubes is 33–50 ppm acetone, which is 13 times larger than that of pure α-Fe₂O₃ nanotubes. The lowest detection limit of acetone is 500 ppb to which the response is 2.3 at the optimum operating temperature of 240 °C. The response and recovery times are about 6 and 11 s to 50 ppm acetone, respectively. In addition, 3 wt% Sm-doped α-Fe₂O₃ nanotubes exhibit good selectivity and long term stability