Enhanced Methane Sensing Properties of WO3 Nanosheets with Dominant Exposed (200) Facet via Loading of SnO2 Nanoparticles

Abstract

Methane detection is extremely difficult, especially at low temperatures, due to its high chemical stability. Here, WO3 nanosheets loaded with SnO2 nanoparticles with a particle size of about 2 nm were prepared by simple impregnation and subsequent calcination using SnO2 and WO3·H2O as precursors. The response of SnO2-loaded WO3 nanosheet composites to methane is about 1.4 times higher than that of pure WO3 at the low optimum operating temperature (90 °C). Satisfying repeatability and long-term stability are ensured. The dominant exposed (200) crystal plane of WO3 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 SnO2-WO3 interface and additionally the increase of specific surface area and defect density via SnO2 loading enhance the response further. Therefore, the SnO2-WO3 composite is promising for the development of sensor devices to methane.

Improvement of Ethanol Gas-Sensing Responses of ZnO–WO3 Composite Nanorods through Annealing Induced Local Phase Transformation

“…It also has advantages of low cost, high chemical stability, and excellent process-dependent reproducibility. Recent progress has shown that WO 3 with various morphologies is promising in applications of gas sensors to detect toxic gases [8,9,10]. Moreover, WO 3 crystals can be synthesized through various physical and chemical methods and the crystalline quality and morphology can be easy controlled through varying the process conditions.…”

Enhancement of Acetone Gas-Sensing Responses of Tapered WO3 Nanorods through Sputtering Coating with a Thin SnO2 Coverage Layer

“…Among numerous applications, WO 3 with various morphologies has received extensive attention as a forward-looking gas-sensing material due to its high sensitivity and stability toward target gases [1,5]. For example, it has been used to detect methane vapor, NO 2 gas, and CO gas with distinct sensing responses [1,6]. However, WO 3 has various crystallographic structures [2].…”

“…WO 3 nanosheets loaded with SnO 2 nanoparticles exhibit enhanced methane-sensing performance. Moreover, it has been shown that the loading content of SnO 2 nanoparticles has an important influence on the sensing behavior of WO 3 –SnO 2 nanocomposites [6].…”

“…It has been used to detect methanol, ethanol, and ethylene glycol gases with desirable sensing performance [14,15,16]. Although improvement in the gas-sensing performance of SnO 2 nanoparticle-decorated monoclinic WO 3 nanosheets and tetragonal SnO 2 -monoclinic WO 3 composite films has been reported [4,6], gas-sensing properties of hexagonally structured WO 3 nanorods coupled with thin coverage layers of SnO 2 have not yet been proposed. This might hinder the potential applications of hexagonally structured WO 3 -based composite nanorods in gas sensor devices.…”

Nanostructured metal oxide semiconductor-based sensors for greenhouse gas detection: progress and challenges

“…SnO 2 -loaded WO 3 nanosheets showed 1.4 times higher response towards CH 4 than pure WO 3 at working temperature of 90°C. The highly reactive sites as a result of defect formation at the SnO 2 -loaded WO 3 heterojunction, and oxygen chemisorptions at the dangling bonds of W atoms of WO 3 nanosheets result in significant enhancement in the sensing behaviour [ 166 ]. The V 2 O 5 nanostructures-based sensor showed a response of about 6.52–8% at 150°C towards 50–500 ppm CH 4 concentration and exhibited its specificity towards the C–H bond (CH 4 ) [ 174 , 177 ].…”