Preparation of Gas Sensors by Hollow SnO2 Electrospun Nanofibers

This work investigated the preparation of tin dioxide (SnO $_{{2}}{)}$ nanofibers with hollow structures by combining the electrostatic spinning technique with the calcination process. The morphology was observed by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and characterization of the chemical state of the elements using X-ray photoelectron spectroscopy (XPS). In gas-sensitive tests on various gases, we found that the response of SnO2 hollow nanofibers to ethanol at a concentration of 100 ppm reached 27.13 when the temperature reached 350 °C as the optimum temperature. Response and recovery times were 42 and 35 s, respectively, and the theoretical detection limit of the sensor was as low as 2.944 ppm. For the enhanced response, the adsorption mechanism of ethanol gas could be attributed to electron transfer on the surface of tin dioxide and followed through impedance change. With the help of density functional theory (DFT) calculations, we demonstrate that the adsorption mechanism of ethanol gas is due to the impedance change caused by the electron transfer on the surface of tin dioxide, which is more selective with ethanol gas.