In this study, a series of undoped and Eu-doped SnO2 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 Eu3+ ions are successfully doped into the SnO2 lattice. Compared with pure SnO2 nanofibers, Eu-doped SnO2 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 SnO2 nanofibers shows the highest response (32.2 for 100 ppm), which is two times higher than that of the pure SnO2 sensor at an operating temperature of 280 degrees 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. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.