Nanowires-assembled WO3 nanomesh for fast detection of ppb-level NO2 at low temperature

Abstract

Hierarchical WO 3 nanomesh, assembled from single-crystalline WO 3 nanowires, is prepared via a hydrothermal method using thiourea (Tu) as the morphology-controlling agent. Formation of the hierarchical architecture comprising of WO 3 nanowires takes place via Ostwald ripening mechanism with the growth orientation. The sensor based on WO 3 nanomesh has good electrical conductivity and is therefore suitable as NO 2 sensing material. The WO 3 nanomesh sensor exhibited high response, short response and recovery time, and excellent selectivity towards ppb-level NO 2 at low temperature of 160 ℃. The superior gas performance of the sensor was attributed to the high-purity hexagonal WO 3 with high specific surface area, which gives rise to enhanced surface adsorption sites for gas adsorption. The electron depletion theory was used for explaining the NO 2 -sensing mechanism by the gas adsorption/desorption and charge transfer happened on the surface of WO 3 nanomesh.

First-principles Study on Nanoscale Tungsten Oxide: a Review

“…3) VESTA (Visualization for electronic and structural analysis)程序 [52] [53][54][55] 。为了更深入地从微 观角度解释氧化钨对气体的敏感性机理，研究者利 用第一性原理，探究了 O3 [56] 、CO [51,[56][57][58] 、丙酮 [27] 、 HCHO [59] 、NO [60] 、NO2 [24,[61][62][63] 等典型气体在 WO3 表 面的吸附及其气敏检测问题。 氧化钨的不同表面及相应的表面能会直接影响 气体分子在其上的吸附，有研究发现 WO3(001)表面 的能量最低 [64]…”

Low concentration isopropanol gas sensing properties of Ag nanoparticles decorated In2O3 hollow spheres

“…The general VOC detection methods include gas chromatography-mass spectrometry (GC-MS) [13,14], ion mobility spectrometry (IMS) [15], gold nanoparticle sensor array [16], and semiconductor metal oxide sensor [17,18]. Among them, semiconductor metal oxide sensor has a good prospect for VOC detection because of its great sensitivity, fast response, lower cost, as well as simple fabrication [19,20]. Metaloxide sensors (MOSs) consist of an insulating substrate fitted with a pair of electrodes covered with a semiconducting metal oxide as the sensitive layer [21,22].…”

Electrospun Cu-doped In2O3 hollow nanofibers with enhanced H2S gas sensing performance

“…In recent years, metal oxide semiconductors (MOSs), such as ZnO, In 2 O 3 , SnO 2 , TiO 2 , CuO, and WO 3 [8][9][10][11][12][13], have been widely used for detecting various gases (involving NO 2 [14], CO [15], H 2 S [16], Cl 2 [17], ethanol [18], acetone [19], etc.) due to the advantages of high sensitivity, good selectivity, fast response and recovery characteristics, and long-term stability [20].…”