scholarly journals Room temperature and high response ethanol sensor based on two dimensional hybrid nanostructures of WS2/GONRs

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hassan Ahmadvand ◽  
Azam Iraji zad ◽  
Raheleh Mohammadpour ◽  
Seyed Hossein Hosseini-Shokouh ◽  
Elham Asadian
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Xrd Analysis ◽  
High Response ◽  
Hybrid Nanostructures ◽  
Molar Ratio ◽  
Two Dimensional ◽  
X Ray ◽  
Bending Radius ◽  
Gas Response

Abstract Here in this research, room temperature ethanol and humidity sensors were prepared based on two dimensional (2D) hybrid nanostructures of tungsten di-sulfide (WS2) nanosheets and graphene oxide nanoribbons (GONRs) as GOWS. The characterization results based on scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (ESD), Raman spectroscopy and X-ray diffraction (XRD) analysis confirmed the hybrid formations. Ethanol sensing of drop-casted GOWS films on SiO2 substrate indicated increasing in gas response up to 5 and 55 times higher compared to pristine GONRs and WS2 films respectively. The sensing performance of GOWS hybrid nanostructures was investigated in different concentrations of WS2, and the highest response was about 126.5 at 1 ppm of ethanol in 40% relative humidity (R.H.) for WS2/GONRs molar ratio of 10. Flexibility of GOWS was studied on Kapton substrate with bending radius of 1 cm, and the gas response decreased less than 10% after 30th bending cycles. The high response and flexibility of the sensors inspired that GOWS are promising materials for fabrication of wearable gas sensing devices.

Facile Synthesis of Hierarchical CuO Microspheres and their Gas Sensing Properties for NOx at Room Temperature

2015 ◽  
Vol 68 (10) ◽  
pp. 1569 ◽  
Author(s):  
Wanzhen Song ◽  
Hongyuan Wu ◽  
Jingchao Wang ◽  
Yufei Lin ◽  
Jiabao Song ◽  
...  
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Gas Diffusion ◽  
Two Dimensional ◽  
Facile Synthesis ◽  
Short Response Time ◽  
Gas Sensing Properties ◽  
Gas Response ◽  
Cuo Microspheres ◽  
Unique Hierarchical Structure

In this research, hierarchical CuO microspheres have been successfully synthesised by a facile reflux method. Scanning electron microscopy results clearly revealed that the hierarchical CuO microspheres were composed of two-dimensional nanosheets. The morphology of the prepared products could be tailored by changing the precursor concentration. The CuO-2 sample shows a higher NOx gas sensing performance with a low detection limit of 0.97 ppm, high gas response of 64.93 %, and short response time of 5.33 s to 97.0 ppm NOx at room temperature. The CuO-2 sensor also presents good selectivity and stability. The significantly improved gas response was concluded to be related to the well aligned microstructures and the improved conductivity of the CuO-2 sample. The unique hierarchical structure allows effective and rapid gas diffusion towards the sensing surfaces. In addition, the sensing mechanism based on the hierarchical CuO microspheres is discussed.

scholarly journals Crystal structure of the new hybrid material bis(1,4-diazoniabicyclo[2.2.2]octane) di-μ-chlorido-bis[tetrachloridobismuthate(III)] dihydrate

2015 ◽  
Vol 71 (11) ◽  
pp. 1384-1387
Author(s):  
Marwen Chouri ◽  
Habib Boughzala
Keyword(s):  
Crystal Structure ◽  
Aqueous Solution ◽  
Hydrogen Bonds ◽  
Room Temperature ◽  
Molar Ratio ◽  
Water Molecules ◽  
Site Symmetry ◽  
Two Dimensional ◽  
Slow Evaporation ◽  
Solution Ph

The title compound bis(1,4-diazoniabicyclo[2.2.2]octane) di-μ-chlorido-bis[tetrachloridobismuthate(III)] dihydrate, (C6H14N2)2[Bi2Cl10]·2H2O, was obtained by slow evaporation at room temperature of a hydrochloric aqueous solution (pH = 1) containing bismuth(III) nitrate and 1,4-diazabicyclo[2.2.2]octane (DABCO) in a 1:2 molar ratio. The structure displays a two-dimensional arrangement parallel to (100) of isolated [Bi2Cl10]4−bioctahedra (site symmetry -1) separated by layers of organic 1,4-diazoniabicyclo[2.2.2]octane dications [(DABCOH2)2+] and water molecules. O—H...Cl, N—H...O and N—H...Cl hydrogen bonds lead to additional cohesion of the structure.

Morphology of Silver Thin Films Deposited on TiO2(110) Surfaces

1998 ◽  
Vol 05 (01) ◽  
pp. 387-392 ◽  
Author(s):  
D. Abriou ◽  
D. Gagnot ◽  
J. Jupille ◽  
F. Creuzet
Keyword(s):  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Oxygen Vacancies ◽  
Two Dimensional ◽  
Silver Films ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Silver Deposits ◽  
Silver Thin Films

The growth mode of silver films deposited at room temperature on TiO 2(110) surfaces has been examined by means of atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) in ultrahigh vacuum (UHV) conditions, On clean vacancy-free TiO 2(110) surfaces, 0.1-nm-thick (on average) Ag deposits form a two-dimensional (2D) layer. When the thickness of the silver overlayer is increased, 3D clusters are shown to appear while the 2D film is preserved, furthermore, the influence of surface oxygen vacancies on the growth of Ag/TiO 2(110) is evidenced by well-characterized differences in the morphology of 9-nm-thick silver deposits.

A Novel Tungsten Trioxide Based Gas Sensor for Indoor Formaldehyde Detection

2021 ◽  
Vol 16 (3) ◽  
pp. 363-367
Author(s):  
Gaoqi Zhang ◽  
Fan Zhang ◽  
Kaifang Wang ◽  
Tao Tian ◽  
Shanyu Liu ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Gas Sensor ◽  
Indoor Air ◽  
Gas Sensing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sensing Material ◽  
Transmission Electron ◽  
Gas Sensing Properties ◽  
Gas Response

Accurate and real-time detection of formaldehyde (HCHO) in indoor air is urgently needed for human health. In this work, a ceramic material (WO3·H2O) with unique structure was successfully prepared using an efficient hydrothermal method. The crystallinity, morphology and microstructure of the as-prepared sensing material were analyzed by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) as well as transmission electron microscope (TEM). The characterization results suggest that the as-prepared sample is composed of square-like nanoplates with uneven surface. Formaldehyde vapor is utilized as the target gas to investigate gas sensing properties of the synthesized novel nanoplates. The testing results indicate that the as-fabricated gas sensor exhibit high gas response and excellent repeatability to HCHO gas. The response value (Ra/Rg) is 24.5 towards 70 ppm HCHO gas at 350 °C. Besides, the gas sensing mechanism was described.

Dielectric Properties and Raman Spectroscopy in Ca-Substituted Na0.5Bi0.5TiO3 Ferroelectric Ceramics

2011 ◽  
Vol 324 ◽  
pp. 298-301 ◽  
Author(s):  
Roy Jean Roukos ◽  
Olivier Bidault ◽  
Julien Pansiot ◽  
Ludivine Minier ◽  
Lucien Saviot
Keyword(s):  
Raman Spectroscopy ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Rhombohedral Phase ◽  
Xrd Analysis ◽  
Solid State Reaction Method ◽  
Ferroelectric Ceramics ◽  
Dielectric Measurements ◽  
X Ray Diffraction ◽  
X Ray

Lead free Na0.5Bi0.5TiO3 (NBT) and (Na0.5Bi0.5TiO3)1-x(CaTiO3)x (NBT-CT) piezoelectric ceramics with the perovskite structure were studied. The NBT and NBT-CT samples were synthesized using a solid-state reaction method and characterized with X-ray diffraction (XRD), Raman spectroscopy and dielectric measurements for several compositions (x = 0, 0.07, 0.15) at room temperature. The XRD analysis showed a stabilization of a rhombohedral phase at a low concentration of Ca (0 < x <0.15), whereas Raman spectra reveal a strong modification for the sample with x = 0.15. The dielectric properties of these ceramics were studied by measuring impedance in the 79-451K temperature range for unpoled and field cooling with an electric field (FC) conditions.

Two-dimensional NiO nanosheets with enhanced room temperature NO2sensing performance via Al doping

2017 ◽  
Vol 19 (29) ◽  
pp. 19043-19049 ◽  
Author(s):  
Shuai Wang ◽  
Da Huang ◽  
Shusheng Xu ◽  
Wenkai Jiang ◽  
Tao Wang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Two Dimensional ◽  
Al Doping ◽  
Sensing Properties ◽  
Gas Sensing Properties ◽  
Nio Nanosheets

Defects caused by Al3+doping significantly affect the gas-sensing properties of NiO nanosheets.

Facile Synthesis of 4,5-Dihydro-1,3,4-Thiadiazoles by 1,3-Dipolar Cycloaddition of Thioisomünchnones

2009 ◽  
Vol 62 (4) ◽  
pp. 356 ◽  
Author(s):  
Bárbara Sánchez ◽  
José Luis Bravo ◽  
María Josí Arívalo ◽  
Ignacio López ◽  
Mark E. Light ◽  
...  
Keyword(s):  
Structure Analysis ◽  
Structure Elucidation ◽  
Room Temperature ◽  
Dipolar Cycloaddition ◽  
Two Dimensional ◽  
Facile Synthesis ◽  
X Ray ◽  
Mild Conditions ◽  
Nmr Techniques

The present paper summarizes a straightforward synthesis of 4,5-dihydro-1,3,4-thiadiazoles by the 1,3-dipolar cycloaddition of thioisomünchnones. These reactions have been carried out in dichloromethane and are essentially complete within 60 min at room temperature. Under such mild conditions the asymmetric version has been explored as well. Unequivocal structure elucidation has been accomplished by means of one- and two-dimensional NMR techniques as well as X-ray structure analysis.

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

Nanomaterials ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 864 ◽  
Author(s):  
Yuan-Chang Liang ◽  
Yu Chao
Keyword(s):  
Gas Sensing ◽  
Microstructural Analysis ◽  
Xrd Analysis ◽  
Thin Layers ◽  
Elemental Distribution ◽  
Distribution Analysis ◽  
Acetone Vapor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Composite Nanorods

WO3–SnO2 composite nanorods were synthesized by combining hydrothermal growth of tapered tungsten trioxide (WO3) nanorods and sputter deposition of thin SnO2 layers. Crystalline SnO2 coverage layers with thicknesses in the range of 13–34 nm were sputter coated onto WO3 nanorods by controlling the sputtering duration of the SnO2. The X-ray diffraction (XRD) analysis results demonstrated that crystalline hexagonal WO3–tetragonal SnO2 composite nanorods were formed. The microstructural analysis revealed that the SnO2 coverage layers were in a polycrystalline feature. The elemental distribution analysis revealed that the SnO2 thin layers homogeneously covered the surfaces of the hexagonally structured WO3 nanorods. The WO3–SnO2 composite nanorods with the thinnest SnO2 coverage layer showed superior gas-sensing response to 100–1000 ppm acetone vapor compared to other composite nanorods investigated in this study. The substantially improved gas-sensing responses to acetone vapor of the hexagonally structured WO3 nanorods coated with the SnO2 coverage layers are discussed in relation to the thickness of SnO2 coverage layers and the core–shell configuration of the WO3–SnO2 composite nanorods.

Synthesis and Effect of Some Parameters through Reverse Micelles Route of Iron Oxide Nanoparticles

2009 ◽  
Vol 152-153 ◽  
pp. 205-208 ◽  
Author(s):  
H. Arabi ◽  
S. Nateghi ◽  
S. Sadeghi
Keyword(s):  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
Reverse Micelles ◽  
Room Temperature ◽  
Molar Ratio ◽  
Oxide Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Significant Difference ◽  
Vibration Sample Magnetometer

Iron oxide nanoparticles were synthesis by reverse micelle method. X-ray diffraction technique and vibration sample magnetometer were applied to characterize the produced samples at different conditions and parameters for synthesis route. There is no significant difference between samples prepared at 5°C and room temperature except a better crystalline at room temperature. The molar ratio of water to surfactant (w parameter) and concentration of the salt solution on size and magnetic properties of nanoparticles have been investigated. Increasing w leads to producing particles with larger size i.e. for w=16.83, 11.22, and 5.6, particles size are 15.22, 11.66 and 10.5 nm, respectively. The size of nanoparticles are in the range of 9 to 20 nanometers

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