Synthesis and gas sensing properties of molybdenum oxide modified tungsten oxide microstructures for ppb-level hydrogen sulphide detection

Abstract

Flower-like MoO3@WO3 composite microstructures with abundant nanosheets were obtained by the hydrothermal and impregnation method and then used for high performance sensing of H2S.

Mesoporous Molybdenum–Tungsten Mixed Metal Oxide: A Solid Acid Catalyst for Green, Highly Efficient sp3–sp2 C–C Coupling Reactions

“…The oxidation states of the elements present in α-Mo 0.5 W 0.5 O 3 mixed oxide were obtained by XPS (Figure g–i). The peaks corresponding to Mo 6+ 3d 5/2 and Mo 6+ 3d 3/2 were observed at 233.1 and 236.2 eV. , The energy separation of 3.1 eV is in accordance with the literature . The low-intensity spin doublet corresponding to Mo 5+ was observed at 231.8 and 234.7 eV .…”

“…Mesoporous molybdenum oxide (MoO 3 ) and tungsten oxide (WO 3 ) have been studied extensively due to their wide range of applications in catalysis, − gas sensors, − electrochromic/photochromic devices, − and energy storage devices. − Thus, the combination of molybdenum and tungsten would open up new avenues with enhanced properties. However, there are only few reports on molybdenum tungsten mixed oxides due to difficulties associated with conventional synthesis methods which are wet impregnation, , sputter deposition, , and electrodeposition. − The direct reaction between MoO 3 and WO 3 involves sintering for long periods of time (5 days) .…”

Electrically-Transduced Chemical Sensors Based on Two-Dimensional Nanomaterials

“…The resulting chemiresistor was capable of detecting 20 ppb H 2 S with a response time of 2 s and a recovery time of 5 s at 250 °C. 614 The excellent gas sensing performance of the MO 3 -WO 3 samples might be ascribed to the heterojunction structure in which a thicker electron depletion layer forms at the interface between MoO 3 and WO 3 , resulting in larger resistance change compared to the pure WO 3 .…”

“…Hu et al reported on ultra-fast detection time at sub-ppm concentrations of H 2 S by integrating MO 3 -WO 3 composite, synthesized by stirring WO 3 nanosheets with definite amounts of ammonium heptamolybdate tetrahydrate in H 2 O followed by calcination at 500 °C, into a gas sensor. The resulting chemiresistor was capable of detecting 20 ppb H 2 S with a response time of 2 s and a recovery time of 5 s at 250 °C . The excellent gas sensing performance of the MO 3 -WO 3 samples might be ascribed to the heterojunction structure in which a thicker electron depletion layer forms at the interface between MoO 3 and WO 3 , resulting in larger resistance change compared to the pure WO 3 .…”

Enhanced Triethylamine Sensing Properties by Designing an α-Fe2O3/α-MoO3 Nanostructure Directly Grown on Ceramic Tubes

“…In comparison with the one-dimensional α-MoO 3 sensor, the 2D sheet-shaped α-MoO 3 sensor has a relatively large specific surface area, thus exposing a large number of adsorption sites to gas molecules. For this reason, 2D sheet-shaped α-MoO 3 sensors exhibit excellent gas-detecting functions for a great many gases, like NO 2 , NH 3 , H 2 S, H 2 , ethanol, acetone, and trimethylamine . For example, Jiang et al prepared MoO 3 microsheets by thermally oxidizing the MoO 2 nanospheres, and the sensitivity of the MoO 3 microsheet sensor to 100 ppm TEA was 27.1.…”