Enhanced Methane Sensing Properties of WO(3) Nanosheets with Dominant Exposed (200) Facet via Loading of SnO(2) Nanoparticles

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.