Design of WO3-SnO2 core-shell nanofibers and their enhanced gas sensing performance based on different work function

In this work, core-shell WO 3 -SnO 2 (CS-WS) nanofibers (NFs) have been successfully synthesized via a coaxial electrospinning approach. The structure and morphology characteristics of the resultant products were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectra (XPS). To investigate the sensing mechanism of the CS-WS NFs, sensors based on SnO 2 NFs, WO 3 NFs, and SnO 2 -WO 3 composite NFs were fabricated respectively, and their gas sensing properties were investigated by using CO, ethanol, toluene, acetone, and ammonia as the test gas. The results indicated that the CS-WS NFs exhibited a good response to ethanol (5.09 at 10 ppm) and short response/recovery time (18.5 s and 282 s) compared with the other test gases. The enhanced ethanol sensing properties of CS-WS NFs compared with those of SnO 2 NFs were closely associated with the CS structure and its derivative effect due to the different work function of SnO 2 and WO 3 . The approach proposed in this study may contribute to the realization of more sensitive metal oxide semiconductor (MOS) core-shell heterostructure sensors.