The results indicated that among all the samples (0, 1, 3 and 5 mol% Co-doped SnO2 nanofibers), 3 mol% Co-doped SnO2 nanofibers showed the highest response toward 100 ppm ethanol, having a response of 40.1, which was over 4 times higher than pure SnO2 nanofibers. At the same time, the sensors based on 3 mol% Co-doped SnO2 nanofibers a