The fabrication and gas-sensing characteristics of the formaldehyde gas sensors with high sensitivity

2008 ◽  
Vol 131 (1) ◽  
pp. 301-305 ◽  
Author(s):  
T. Chen ◽  
Q.J. Liu ◽  
Z.L. Zhou ◽  
Y.D. Wang
Keyword(s):  
Gas Sensors ◽  
Gas Sensing ◽  
High Sensitivity ◽  
Sensing Characteristics

scholarly journals Effects of palladium on the optical and hydrogen sensing characteristics of Pd-doped ZnO nanoparticles

2014 ◽  
Vol 5 ◽  
pp. 1261-1267 ◽  
Author(s):  
Anh-Thu Thi Do ◽  
Hong Thai Giang ◽  
Thu Thi Do ◽  
Ngan Quang Pham ◽  
Giang Truong Ho
Keyword(s):  
Gas Sensors ◽  
Continuous Monitoring ◽  
Gas Sensing ◽  
Deep Level ◽  
Green Emission ◽  
High Sensitivity ◽  
Response Characteristics ◽  
Hydrogen Sensing ◽  
Sensitivity And Selectivity ◽  
Sensing Characteristics

The effect of palladium doping of zinc oxide nanoparticles on the photoluminescence (PL) properties and hydrogen sensing characteristics of gas sensors is investigated. The PL intensity shows that the carrier dynamics coincides with the buildup of the Pd-related green emission. The comparison between the deep level emission and the gas sensing response characteristics allows us to suggest that the dissociation of hydrogen takes place at PdZn-vacancies ([Pd 2+(4d9)]). The design of this sensor allows for a continuous monitoring in the range of 0–100% LEL H2 concentration with high sensitivity and selectivity.

Fabricating ZnO Nanorods Sensor for Chemical Gas Detection at Room Temperature

2007 ◽  
Vol 7 (12) ◽  
pp. 4439-4442 ◽  
Author(s):  
Chuanwei Cheng ◽  
Guoyue Xu ◽  
Haiqian Zhang ◽  
Yan Luo
Keyword(s):  
Gas Sensors ◽  
Potential Application ◽  
Room Temperature ◽  
Gas Sensing ◽  
Zno Nanorods ◽  
High Sensitivity ◽  
Gas Detection ◽  
Highly Sensitive ◽  
Sensing Characteristics

We present a sensor fabricated by simply casting ZnO nanorods on a microelectrodes array for chemical gas detection at room temperature. The ammonia and ethanol gas sensing characteristics were carefully investigated. The sensor exhibited high sensitivity for both ammonia and ethanol gases. The response and recover time are less than 20 seconds, respectively. Present results demonstrate the potential application of ZnO nanorods for fabricating highly sensitive gas sensors.

scholarly journals Discriminable Sensing Response Behavior to Homogeneous Gases Based on n-ZnO/p-NiO Composites

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 785 ◽  
Author(s):  
Wen-Dong Zhou ◽  
Davoud Dastan ◽  
Jing Li ◽  
Xi-Tao Yin ◽  
Qi Wang
Keyword(s):  
Gas Sensors ◽  
Gas Sensing ◽  
Sol Gel ◽  
High Sensitivity ◽  
Oxide Semiconductor ◽  
Sensing Properties ◽  
Gas Sensing Properties ◽  
P Type ◽  
Type Response ◽  
Properties Of Composites

Metal oxide semiconductor (MOS) gas sensors have the advantages of high sensitivity, short response-recovery time and long-term stability. However, the shortcoming of poor discriminability of homogeneous gases limits their applications in gas sensors. It is well-known that the MOS materials have similar gas sensing responses to homogeneous gases such as CO and H2, so it is difficult for these gas sensors to distinguish the two gases. In this paper, simple sol–gel method was employed to obtain the ZnO–xNiO composites. Gas sensing performance results illustrated that the gas sensing properties of composites with x > 0.425 showed a p-type response to both CO and H2, while the gas sensing properties of composites with x < 0.425 showed an n-type response to both CO and H2. However, it was interesting that ZnO–0.425NiO showed a p-type response to CO but an discriminable response (n-type) to H2, which indicated that modulating the p-type or n-type semiconductor concentration in p-n composites could be an effective method with which to improve the discriminability of this type of gas sensor regarding CO and H2. The phenomenon of the special gas sensing behavior of ZnO–0.425NiO was explained based on the experimental observations and a range of characterization techniques, including XRD, HRTEM and XPS, in detail.

scholarly journals Preparation of Flower-Like Cu-WO3Nanostructures and Their Acetone Gas Sensing Performance

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Hao Zhou ◽  
Dong-Yao Xu ◽  
Hai-Qing Zuo ◽  
Wei Liu ◽  
Shuang Lin
Keyword(s):  
Gas Sensors ◽  
Gas Sensing ◽  
Hydrothermal Process ◽  
High Sensitivity ◽  
Test System ◽  
Static State ◽  
Acetone Concentration ◽  
Detection Range ◽  
Gas Sensing Properties ◽  
Linear Fit

Urchin-like Cu-W18O49and flower-like Cu-WO3structures were successfully synthesized using a hydrothermal process followed by calcination. The synthesized products were characterized using XRD, SEM, and TEM. The results revealed that the as-prepared urchin-like and flower-like samples with monoclinic structures, which were approximately 1 μm and 1-2 μm, respectively, possessed microflower architecture assembled by the nanosheet. In addition, the gas sensing properties of monoclinic-structured Cu-WO3to acetone were measured using a static state gas sensing test system. The sensor based on the flower-like Cu-WO3nanostructures, which were calcined at 600°C, exhibited high sensitivity toward 10 ppm acetone at an optimum temperature of 110°C, and the maximum sensitivity reached 40, which was approximately four times higher than that of urchin-like WO3that was annealed at 300°C. The sensitivity was improved by increasing the acetone concentration. The detection limit was as low as 1 ppm. Using linear fit, the sensor was determined to be sufficiently sensitive to detect acetone in a detection range of 1 to 10 ppm even in the presence of interfering gases, which suggests that this type of sensor has excellent selectivity and has the potential for use in acetone gas sensors in the future.

scholarly journals Embedded Transdermal Alcohol Detection via a Finger Using SnO2 Gas Sensors

Sensors ◽  
2021 ◽  
Vol 21 (20) ◽  
pp. 6852
Author(s):  
Fatima Ezahra Annanouch ◽  
Virginie Martini ◽  
Tomas Fiorido ◽  
Bruno Lawson ◽  
Khalifa Aguir ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Tin Dioxide ◽  
Gas Sensing ◽  
Low Cost ◽  
High Sensitivity ◽  
Rf Magnetron Sputtering ◽  
Alcohol Concentration ◽  
Invasive Technique ◽  
Clear Correlation ◽  
Wide Range

In this paper, we report the fabrication and characterization of a portable transdermal alcohol sensing device via a human finger, using tin dioxide (SnO2) chemoresistive gas sensors. Compared to conventional detectors, this non-invasive technique allowed us the continuous monitoring of alcohol with low cost and simple fabrication process. The sensing layers used in this work were fabricated by using the reactive radio frequency (RF) magnetron sputtering technique. Their structure and morphology were investigated by means of X-ray spectroscopy (XRD) and scanning electron microscopy (SEM), respectively. The results indicated that the annealing time has an important impact on the sensor sensitivity. Before performing the transdermal measurements, the sensors were exposed to a wide range of ethanol concentrations and the results displayed good responses with high sensitivity, stability, and a rapid detection time. Moreover, against high relative humidity (50% and 70%), the sensors remained resistant by showing a slight change in their gas sensing performances. A volunteer (an adult researcher from our volunteer group) drank 50 mL of tequila in order to realize the transdermal alcohol monitoring. Fifteen minutes later, the volunteer’s skin started to evacuate alcohol and the sensor resistance began to decline. Simultaneously, breath alcohol measurements were attained using a DRAGER 6820 certified breathalyzer. The results demonstrated a clear correlation between the alcohol concentration in the blood, breath, and via perspiration, which validated the embedded transdermal alcohol device reported in this work.

2D/2D/2D Ti3C2Tx@TiO2@MoS2 Heterostructure as Ultrafast and High-sensitivity NO2 Gas Sensor at Room-temperature

2022 ◽  
Author(s):  
Zhuo Liu ◽  
He Lv ◽  
Ying Xie ◽  
Jue Wang ◽  
Jiahui Fan ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Gas Sensors ◽  
Room Temperature ◽  
Gas Sensing ◽  
2D Materials ◽  
High Sensitivity ◽  
Two Dimensional ◽  
No2 Gas Sensor ◽  
2D Structure ◽  
Sensing Application

The very diverse two-dimensional (2D) materials have bloomed in NO2 gas sensing application that provide new opportunities and challenges in function oriented gas sensors. In this work, a 2D/2D/2D structure...

Formation of Highly Porous Gas-sensing Films by In-situ Thermophoretic Deposition of Nanoparticles from Aerosol Phase

2006 ◽  
Vol 915 ◽  
Author(s):  
Thorsten Sahm ◽  
Weizhi Rong ◽  
Nicolae Barsan ◽  
Lutz Mädler ◽  
Sheldon K. Friedlander ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Tin Dioxide ◽  
Gas Sensing ◽  
High Sensitivity ◽  
High Catalytic Activity ◽  
Flame Spray ◽  
Ceramic Substrates ◽  
Pd Doping ◽  
Sensor Signals

AbstractGas sensors based on tin dioxide nanoparticles show high sensitivity to reducing and oxidizing gases. Dry aerosol synthesis applying the flame spray pyrolysis was used for manufacture and directly (in-situ) deposit nanoparticles on sensor substrates. For the first time this technique has been used to synthesize a combination of two stacked porous layers for gas sensor fabrication. Compared to state-of-the-art techniques, aerosol technology provides a direct and versatile method to produce homogeneous nanoparticle films. Two different sensing layers were deposited directly on interdigital ceramic substrates. These porous bottom layers consisted either of pure tin dioxide or palladium doped tin dioxide. The top layer was a palladium doped alumina nanoparticle film which served as a chemical filter. The fabricated gas sensors were tested with methane, CO and ethanol. In case of CH4 detection, the pure tin dioxide sensor with the Pd/Al2O3 filter layer showed higher sensor signals and significantly improved analyte selectivity with respect to water vapor compared to single tin dioxide films. At temperatures up to 250°C the Pd-doping of the tin dioxide strongly increased the sensitivity to all gases. At higher temperatures the sensor signal significantly decreased for the Pd/SnO2 sensor with a Pd/Al2O3 filter on top indicating high catalytic activity.

Spay Pyrolyzed Nanostructured Tin Dioxide Thin Films Doped by Cobalt: Correlation between Structural and Gas Sensing Characteristics

2013 ◽  
Vol 377 ◽  
pp. 180-185
Author(s):  
Ghenadii Korotcenkov ◽  
Iulia Boris ◽  
Vladimir Brinzari ◽  
Beongki Cho
Keyword(s):  
Thin Films ◽  
Spray Pyrolysis ◽  
Structural Properties ◽  
Gas Sensors ◽  
Tin Dioxide ◽  
Gas Sensing ◽  
Co Doping ◽  
Low Levels ◽  
Sensing Characteristics ◽  
Operation Characteristics

Effect of Co-doping on gas sensing, electrophysical and structural properties of the SnO2films deposited by spray pyrolysis has been studied. It is found that the influence of Co-doping on parameters of the SnO2-based gas sensors depends on the concentration of doping additives and could be accompanied by either improvement of sensor parameters at low levels of doping (CCo< 2-4 %) or degradation of the gas sensor operation characteristics while the concentration of additives exceeds 2-4%. An explanation of observed effects is given.

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