Gas sensor based on TiO2 nanofibers decorated with monodispersed WO3 nanocubes for fast and selective xylene detection

WO 3 -TiO 2 heterostructural nanofibers (HNFs) were prepared by a simple two-step process. The structures, chemical constitutions and morphologies of the samples were characterized by various kinds of techniques, including XRD, XPS, EDX, SEM and TEM. The results suggested that WO 3 nanocubes with a size range of 80–120 nm were decorated uniformly on the surface of TiO 2 nanofibers in the WO 3 -TiO 2 samples. XPS results confirmed the existence of W 5+ and the increased amount of both chemisorbed oxygen species and oxygen vacancies after the WO 3 nanocubes were decorated on the surface of TiO 2 nanofibers. Compared with the pure materials, the WO 3 -TiO 2 HNFs exhibited higher response, better selectivity and lower limit detection to xylene. The improvement of the performance can be attributed to the formation of heterojunction between TiO 2 and WO 3 and the conversion between W 6+ and W 5+ . The sensing mechanism of the enhanced gas sensing properties was also discussed.