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In this study, a series of undoped and Eu-doped SnO 2 nanofibers were synthesized via a simple electrospinning technique and subsequent calcination treatment. Field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were carefully used to characterize the morphologies, structures and chemical compositions of these samples. The results reveal that the as-prepared nanofibers are composed of crystallite grains with an average size of about 10 nm and Eu 3+ ions are successfully doped into the SnO 2 lattice. Compared with pure SnO 2 nanofibers, Eu-doped SnO 2 nanofibers demonstrate significantly enhanced sensing characteristics (e.g., large response value, short response/recovery time and outstanding selectivity) toward acetone vapor, especially, the optimal sensor based on 2 mol% Eu-doped SnO 2 nanofibers shows the highest response (32.2 for 100 ppm), which is two times higher than that of the pure SnO 2 sensor at an operating temperature of 280 °C. In addition, the sensor exhibits a good sensitivity to acetone in sub-ppm concentrations and the detection limit could extend down to 0.3 ppm, making it a potential candidate for the breath diagnosis of diabetes. [ABSTRACT FROM AUTHOR]

We demonstrated a new metal oxides based chemiresistor (MOC), which exhibits fast response/recovery behavior, large sensitivity, and good selectivity to ethanol, enabled by Sr-doped SnO 2 nanofibers via simple electrospinning and followed by calcination. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectra (XPS) were carefully used to characterize their morphology, structure, and composition. The ethanol sensing performances based on Sr-doped SnO 2 nanofibers were investigated. Comparing with the pristine SnO 2 nanofibers, enhanced ethanol sensing performances (more rapid response/recovery behavior and larger response values) have been achieved owing to the basic SnO 2 surface caused by Sr-doping, whereas the acetone sensing performances have been weakened. Thus, good discriminative ability to ethanol from acetone has been realized. Additionally, Sr-doped SnO 2 nanofibers also exhibit good selectivity. [ABSTRACT FROM AUTHOR]