Pt-Cr2O3-WO3 composite nanofibers as gas sensors for ultra-high sensitive and selective xylene detection

In this work, Pt-Cr 2 O 3 -WO 3 composite nanofibers have been designed by using Pt@MIL-101(Cr) and electrospinning. The morphological and microstructural properties of these nanofibers were analyzed by various kinds of techniques. The FESEM and TEM results demonstrate that the size of Pt nanoparticles is ˜ 3 nm, which greatly improved the gas sensing properties of metal oxides. The gas-sensing properties of WO 3 , Cr 2 O 3 -WO 3 and Pt-Cr 2 O 3 -WO 3 composite nanofibers were tested. Compared with pristine WO 3 nanofibers, Pt-Cr 2 O 3 -WO 3 composite nanofibers exhibit superior response toward xylene. At the optimal operating temperature of 325 °C, the response of Pt-Cr 2 O 3 -WO 3 composite nanofibers to 10 ppm xylene is 74.3, the response time is 5 s and the detection limit is 0.5  ppm. The sensing mechanism of the ultrahigh gas sensing properties attributes to the Cr 2 O 3 -WO 3 heterojunction, the catalytic activity of Cr 2 O 3 , porous structure, the electronic and chemical sensitization of Pt nanoparticles.