Synthesis of novel Ho2O3–Fe2O3 porous nanotubes and their ultra-high acetone-sensing properties

The mono-disperse Ho2O3–Fe2O3 porous nanotubes were successfully synthesized via a facile electrospinning method. The morphologies, crystal structures and components of as-prepared samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Transmission electron microscope (TEM) and High Resolution Transmission Electron Microscopy (HRTEM), respectively. Then the samples were applied to construct gas sensor devices and their gas sensing properties were further investigated. The results showed that the Ho2O3–Fe2O3 porous nanotubes with the weight ratio of 3 wt% exhibit an ultra-high response to acetone (185/100 ppm) at the optimal operating temperature of 240 °C. Meanwhile, the detection limit of the sensor is estimated to be 500 ppb with a response of 2.4. The sensor also owned good linear characteristic (0–200 ppm) and selectivity, demonstrating the sensor based on Ho2O3–Fe2O3 porous nanotubes has a promising application for detecting acetone. Thus, further improvement of gas sensing properties in metal-oxide-semiconductors materials could be realized by forming porous nanocomposite.