scholarly journals Hierarchical Nanoflowers of Colloidal WS2 and Their Potential Gas Sensing Properties for Room Temperature Detection of Ammonia

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1491
Author(s):  
Siziwe S. Gqoba ◽  
Rafael Rodrigues ◽  
Sharon Lerato Mphahlele ◽  
Zakhele Ndala ◽  
Mildred Airo ◽  
...  
Keyword(s):  
Band Gap ◽  
Room Temperature ◽  
Chemical Sensor ◽  
Gas Sensing ◽  
Hierarchical Structures ◽  
Oxide Phase ◽  
Sem Analysis ◽  
Colloidal Synthesis ◽  
Temperature Detection ◽  
Custom Made

A one-step colloidal synthesis of hierarchical nanoflowers of WS2 is reported. The nanoflowers were used to fabricate a chemical sensor for the detection of ammonia vapors at room temperature. The gas sensing performance of the WS2 nanoflowers was measured using an in-house custom-made gas chamber. SEM analysis revealed that the nanoflowers were made up of petals and that the nanoflowers self-assembled to form hierarchical structures. Meanwhile, TEM showed the exposed edges of the petals that make up the nanoflower. A band gap of 1.98 eV confirmed a transition from indirect-to-direct band gap as well as a reduction in the number of layers of the WS2 nanoflowers. The formation of WS2 was confirmed by XPS and XRD with traces of the oxide phase, WO3. XPS analysis also confirmed the successful capping of the nanoflowers. The WS2 nanoflowers exhibited a good response and selectivity for ammonia.

scholarly journals Synthesis of g-C3N4-Decorated ZnO Porous Hollow Microspheres for Room-Temperature Detection of CH4 under UV-Light Illumination

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1507 ◽  
Author(s):  
Min Xiao ◽  
Yanwei Li ◽  
Bo Zhang ◽  
Guang Sun ◽  
Zhanying Zhang
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Uv Light ◽  
Response Speed ◽  
Hollow Microspheres ◽  
Oxide Semiconductor ◽  
Light Illumination ◽  
Long Term Stability ◽  
Temperature Detection ◽  
Good Repeatability

UV light-assisted gas sensors based on metal oxide semiconductor (MOS) have attracted much attention in detecting flammable and explosive gases at room temperature. In this paper, graphite-based carbon nitride (g-C3N4) nanosheets-decorated ZnO porous hollow microspheres (PHMSs) with the size about 3~5 μm in diameter were successfully synthesized by annealing the solvothermally-synthesized Zn5(CO3)2(OH)6 PHMSs together with g-C3N4. The synthesized samples were characterized by XRD, SEM, TEM, FT-IR and XPS. The results indicated that the prepared g-C3N4/ZnO PHMSs were constructed by numerous loosely stacked ZnO nanoparticles of 20~30 nm in diameter. Gas sensing tests indicated that under UV light (365~385 nm) illumination, the sensors fabricated with g-C3N4/ZnO HPMSs showed an enhanced response and faster response speed than the pure ZnO counterpart at room temperature. In addition, the g-C3N4/ZnO sensor also exhibited good repeatability and long-term stability for CH4 detection.

Aerosol-Assisted CVD of SnO2 Thin Films for the Room-Temperature Detection of Hydrogen Sulfide

2013 ◽  
Vol 543 ◽  
pp. 422-425
Author(s):  
Huan Liu ◽  
Min Li ◽  
Jiu Xiao Wan ◽  
Jun Zhao ◽  
Qiu Yun Fu ◽  
...  
Keyword(s):  
Thin Films ◽  
Gas Flow ◽  
Room Temperature ◽  
Gas Sensing ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Temperature Detection ◽  
Low Concentrations ◽  
Initial Resistance ◽  
Deposition Conditions

High-quality SnO2 thin-film materials capable of detecting H2S gas of low concentrations at room temperature was demonstrated in this paper. We employed aerosol-assisted chemical vapor deposition process for the deposition of SnO2 thin films on alumina substrates with pre-patterned electrodes. The gas-sensing performances of the films prepared under different deposition conditions were systematically compared and analyzed. When SnCl2·2H2O was used as the precursor, a response sensitivity of 98.4 toward 50 ppm of H2S at room temperature was achieved. At room temperatures, the resistance upon the H2S gas exposure could recover to 90% of the initial resistance of the sensor when the H2S gas flow was turned off.

ROOM TEMPERATURE AND ELEVATED TEMPERATURE CHARACTERIZATION OF NANOCRYSTALLINE SnO2 SURFACES BY SCANNING TUNNELING MICROSCOPY AND SPECTROSCOPY

2004 ◽  
Vol 03 (04n05) ◽  
pp. 519-524
Author(s):  
T. G. G. MAFFEÏS ◽  
G. T. OWEN ◽  
S. P. WILKS ◽  
C. MALAGÙ ◽  
G. MARTINELLI ◽  
...  
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Band Gap ◽  
Surface Properties ◽  
Room Temperature ◽  
Gas Sensing ◽  
Low Cost ◽  
Scanning Tunneling ◽  
Full Potential ◽  
Tunneling Microscopy ◽  
Sensing Applications

Semiconductor gas sensors based on nanocrystalline SnO 2 offer many advantages over current technologies for detecting reducing gases, such as low cost, long lifetime, and high selectivity and sensitivity. However, the local surface properties on the nanoscale of SnO 2 nanocrystals are not fully understood, which impedes the exploitation of the full potential of SnO 2 for gas sensing applications. In this paper, we present a scanning tunneling microscopy and spectroscopy (STM/STS) study of nanocrystalline SnO 2 at room temperature, and under standard sensing conditions at 120°C. STS data indicate that the electronic surface properties change with nanoparticle size, temperature and exposure to gas. The surface density of states in the band gap is shown to increase with temperature while CO exposures induce a large drop in the density of band gap states as the CO molecules react with chemisorbed oxygen species.

scholarly journals Highly sensitive and room temperature detection of ultra-low concentrations of O3 using self-powered sensing elements of Cu2O nanocubes

2019 ◽  
Vol 1 (5) ◽  
pp. 2009-2017 ◽  
Author(s):  
E. Petromichelaki ◽  
E. Gagaoudakis ◽  
K. Moschovis ◽  
L. Tsetseris ◽  
T. D. Anthopoulos ◽  
...  
Keyword(s):  
Metal Oxides ◽  
Room Temperature ◽  
Gas Sensing ◽  
Low Cost ◽  
New Class ◽  
Temperature Detection ◽  
Low Concentrations ◽  
Highly Sensitive ◽  
Self Powered ◽  
P Type

The fundamental development of the design of novel self-powered ozone sensing elements, operating at room temperature, based on p-type metal oxides paves the way to a new class of low cost, highly promising gas sensing devices.

scholarly journals Preparation and Gas Sensing Properties of PANI/SnO2 Hybrid Material

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1360
Author(s):  
Qiaohua Feng ◽  
Huanhuan Zhang ◽  
Yunbo Shi ◽  
Xiaoyu Yu ◽  
Guangdong Lan
Keyword(s):  
Hybrid Material ◽  
Room Temperature ◽  
Tin Dioxide ◽  
Gas Adsorption ◽  
Gas Sensing ◽  
Oxidative Polymerization ◽  
Environmental Pollutants ◽  
Decomposition Temperature ◽  
Benzene Vapor ◽  
Thermo Gravimetric Analyzer

A sensor operating at room temperature has low power consumption and is beneficial for the detection of environmental pollutants such as ammonia and benzene vapor. In this study, polyaniline (PANI) is made from aniline under acidic conditions by chemical oxidative polymerization and doped with tin dioxide (SnO2) at a specific percentage. The PANI/SnO2 hybrid material obtained is then ground at room temperature. The results of scanning electron microscopy show that the prepared powder comprises nanoscale particles and has good dispersibility, which is conducive to gas adsorption. The thermal decomposition temperature of the powder and its stability are measured using a differential thermo gravimetric analyzer. At 20 °C, the ammonia gas and benzene vapor gas sensing of the PANI/SnO2 hybrid material was tested at concentrations of between 1 and 7 ppm of ammonia and between 0.4 and 90 ppm of benzene vapor. The tests show that the response sensitivities to ammonia and benzene vapor are essentially linear. The sensing mechanisms of the PANI/SnO2 hybrid material to ammonia and benzene vapors were analyzed. The results demonstrate that doped SnO2 significantly affects the sensitivity, response time, and recovery time of the PANI material.

scholarly journals Mechanical Properties and Corrosion Resistance of TiAl6V4 Alloy Produced with SLM Technique and Used for Customized Mesh in Bone Augmentations

2021 ◽  
Vol 11 (12) ◽  
pp. 5622
Author(s):  
Nicola De Angelis ◽  
Luca Solimei ◽  
Claudio Pasquale ◽  
Lorenzo Alvito ◽  
Alberto Lagazzo ◽  
...  
Keyword(s):  
Sem Analysis ◽  
Bone Augmentation ◽  
Specific Test ◽  
Chemical Action ◽  
Three Point Bending ◽  
Custom Made ◽  
Manufacturing Techniques ◽  
Mechanical Properties And Corrosion ◽  
Flexural Tests ◽  
Applied Stresses

Bone augmentation procedures represent a real clinical challenge. One option is the use of titanium meshes. Additive manufacturing techniques can provide custom-made devices in titanium alloy. The purpose of this study was to investigate the material used, which can influence the outcomes of the bone augmentation procedure. Specific test samples were obtained from two different manufacturers with two different shapes: surfaces without perforations and with calibrated perforations. Three-point bending tests were run as well as internal friction tests to verify the Young’s modulus. Test samples were placed in two different buffered solutions and analyzed with optical microscopy. A further SEM analysis was done to observe any microstructural modification. Three-point flexural tests were conducted on 12 specimens. Initial bending was observed at lower applied stresses for the perforated samples (503 MPa) compared to non-perforated ones (900 MPa); the ultimate flexural strength was registered at 513 MPa and 1145 MPa for perforated and non-perforated samples, respectively. Both microscopic analyses (optical and SEM) showed no significant alterations. Conclusions: A normal masticatory load cannot modify the device. Chemical action in the case of exposure does not create macroscopic and microscopic alterations of the surface.

Synergistic effects of SnO2 and Au nanoparticles decorated on WS2 nanosheets for flexible, room-temperature CO gas sensing

2021 ◽  
Vol 332 ◽  
pp. 129493
Author(s):  
Jae-Hun Kim ◽  
Jin-Young Kim ◽  
Ali Mirzaei ◽  
Hyoun Woo Kim ◽  
Sang Sub Kim
Keyword(s):  
Room Temperature ◽  
Au Nanoparticles ◽  
Gas Sensing ◽  
Synergistic Effects ◽  
Ws2 Nanosheets ◽  
Co Gas

SnS2/MXene derived TiO2 hybrid for ultra-fast room temperature NO2 gas sensing

2021 ◽  
Author(s):  
Tianding CHEN ◽  
Wenhao YAN ◽  
Ying WANG ◽  
Jinli Li ◽  
Haibo Hu ◽  
...  
Keyword(s):  
Nitrogen Dioxide ◽  
Human Health ◽  
Room Temperature ◽  
Gas Sensing ◽  
Air Pollutant

Nitrogen dioxide (NO2) is a prominent air pollutant that is harmful to both the environment and human health. Conventional NO2 sensors that are designed to operate at room temperature often...

Improvement of Gas Sensing of Uniform Ag 3 PO 4 Nanoparticles to NH 3 under the Assistant of LED Lamp with Low Power Consumption at Room Temperature

2021 ◽  
Vol 6 (32) ◽  
pp. 8338-8344
Author(s):  
Xingyan Shao ◽  
Shuo Wang ◽  
Leqi Hu ◽  
Tingting Liu ◽  
Xiaomei Wang ◽  
...  
Keyword(s):  
Power Consumption ◽  
Low Power ◽  
Room Temperature ◽  
Gas Sensing ◽  
Low Power Consumption
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