Porous Eu2O3–In2O3 nanotube-based ethanol gas sensor with high sensitivity and excellent selectivity

In this work, we employed electrospinning and calcination method to fabricate porous Eu2O3–In2O3 nanotubes and observed the morphology and characteristic of products through X-ray diffraction (XRD), energy-dispersive X-ray spectra (EDX), and scanning electron microscopy (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). The SEM and TEM images exhibit that the surface of nanotubes is distributed with numerous pores. Gas-sensing investigations revealed that the 3 wt% porous Eu2O3–In2O3 nanotube sensors possess high sensitivity and excellent selectivity to ethanol. Its response to 50 ppm ethanol was up to 44 at optimum temperature of 260 °C, which is 6.2 times larger than the pure nanotube. The response to ethanol is four times larger than that of acetone. The response and recovery time to 50 ppm ethanol was 3 and 21 s, respectively. Besides, the sensor could detect 0.2 ppm ethanol with response of 1.8. Those indicate that the sensing properties of In2O3 nanotube sensor are improved by doping Eu. In brief, the porous Eu2O3–In2O3 nanotube sensor has hopes for practice.