Ionic liquid-assisted synthesis of InO nanoparticles for ppb-level NO sensing at low temperature.

Highly sensitive detection of nitric dioxide (NO) has recently attracted much attention due to its harmful to the human health even at a low concentration of 0.1 parts per million (ppm). Herein, InO nanoparticles (NPs) were prepared via a facile ionic liquid (IL) assisted solvothermal method with subsequent calcination and then were analyzed through the characterization of X-ray diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and nitrogen adsorption-desorption techniques. Morphological characterization demonstrated that the resultant compounds were InO NPs with a diameter ranging from 20 to 30 nm. The gas sensor based on the InO NPs prepared with IL exhibited excellent NO-sensing properties in terms of fast response/recovery speed (26.6/10.0 s), high response (310.0), good repeatability and long-term stability to 10 ppm NO gas at low working temperature of 92 °C. The gas-sensing mechanism of InO NPs to NO was represented to the surface adsorption control model and the possibilities relating to the improved NO sensing performance of the InO NPs synthesized with IL-assisted were also discussed in detail.