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

Abstract WO3-TiO2 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 WO3 nanocubes with a size range of 80–120 nm were decorated uniformly on the surface of TiO2 nanofibers in the WO3-TiO2 samples. XPS results confirmed the existence of W5+ and the increased amount of both chemisorbed oxygen species and oxygen vacancies after the WO3 nanocubes were decorated on the surface of TiO2 nanofibers. Compared with the pure materials, the WO3-TiO2 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 TiO2 and WO3 and the conversion between W6+ and W5+. The sensing mechanism of the enhanced gas sensing properties was also discussed.