Enhanced methane sensing properties of WO 3 nanosheets with dominant exposed (200) facet via loading of SnO 2 nanoparticles

Abstract

Methane detection is extremely difficult, especially at low temperatures, due to its high chemical stability. Here, WO 3 nanosheets loaded with SnO 2 nanoparticles with a particle size of about 2 nm were prepared by simple impregnation and subsequent calcination using SnO 2 and WO 3 ·H 2 O as precursors. The response of SnO 2 -loaded WO 3 nanosheet composites to methane is about 1.4 times higher than that of pure WO 3 at the low optimum operating temperature (90 ◦ C). Satisfying repeatability and long-term stability are ensured. The dominant exposed (200) crystal plane of WO 3 nanosheets has a good balance between easy oxygen chemisorption and high reactivity at the dangling bonds of W atoms, beneficial for gas-sensing properties. Moreover, the formation of a n–n type heterojunction at the SnO 2 -WO 3 interface and additionally the increase of specific surface area and defect density via SnO 2 loading enhance the response further. Therefore, the SnO 2 -WO 3 composite is promising for the development of sensor devices to methane.