Au-Loaded Hierarchical MoO₃ Hollow Spheres with Enhanced Gas-Sensing Performance for the Detection of BTX (Benzene, Toluene, And Xylene) And the Sensing Mechanism

Abstract

Monodisperse, hierarchical α-MoO hollow spheres were fabricated using a facile template-free solvothermal method combined with subsequent calcination. Various quantities of Au nanoparticles (NPs) were deposited on the α-MoO hollow spheres to construct hybrid nanomaterials for chemical gas sensors and their BTX sensing properties were investigated. The 2.04 wt % Au-loaded α-MoO sensor can detect BTX effectively at 250 °C, especially, its responses to 100 ppm toluene and xylene are 17.5 and 22.1, respectively, which are 4.6 and 3.9 times higher than those of pure α-MoO hollow spheres at 290 °C. Besides, Au loading decreased the response times to toluene and xylene from 19 and 6 s to 1.6 and 2 s, respectively, lowered the working temperature from 290 to 250 °C as compared with those of pure α-MoO. The surface status of Au/α-MoO hollow spheres before and after contacting with toluene at 250 °C was analyzed through XPS technique. Possible oxidization product of toluene was confirmed by GC for the first time. The gas-sensing mechanism of the Au/α-MoO was speculated as the oxidation of toluene to water and carbon dioxide by chemisorbed oxygen and lattice oxygen. The possible reason related with improved gas-sensing properties of the Au-functionalized α-MoO was discussed.

Synthesis of Pd-loaded mesoporous SnO2 hollow spheres for highly sensitive and stable methane gas sensors

“…Furthermore, no obvious diffraction peaks are ascribed to Pd or PdO because the trace amount and small crystalline size are difficult to detect by XRD analysis, which is similar to the reported Pd-SnO 2 microspheres, 39 Pt-SnO 2 microspheres, 43 Au-MoO 3 hierarchical hollow spheres. 13 On the other hand, the surface chemical composition of each element is investigated by XPS analysis. Fig.…”

Au‐nanoparticle‐decorated SnO2 nanorod sensor with enhanced xylene‐sensing performance

“…Moreover, the proportion of surface‐adsorbed oxygen was in the order SnO 2 ≈ 3 mol% Au‐SnO 2 < 12 mol% Au‐SnO 2 . The increased surface‐adsorbed oxygen can greatly enhance the xylene‐sensing performance . Figure D shows the high‐resolution Au 4f spectrum of Au‐SnO 2 NRs.…”

“…The increased surface-adsorbed oxygen can greatly enhance the xylene-sensing performance. 45 Figure 4D shows the highresolution Au 4f spectrum of Au-SnO 2 NRs. The spectrum contained peaks centered at 83.9-84.25 and 87.5-88.05 eV, which correspond to the 4f 7/2 and 4f 5/2 signals of metallic Au, respectively.…”

Recent Progress in Chemiresistive Gas Sensing Technology Based on Molybdenum and Tungsten Chalcogenide Nanostructures

“…A response value of 321 could be achieved for sensors based on Zn doped MoO 3 when exposed to 1000 ppm ethanol at this optimal temperature, which is about 15 times higher than that of pure MoO 3 nanobelts based devices. Sui et al loaded Au nanoparticles on the MoO 3 nanohollow spheres and found the material to possess better BTX sensing capabilities over the pure MoO 3 hollow spheres 237. In particular, 2.04 wt% Au loaded MoO 3 sensor has an optimum operating temperature 40 °C less than pure MoO 3 hollow sphere‐based sensors.…”