A Formaldehyde Indoor Gas Sensor Based on Hierarchical α-Molybdenum Trioxide

2021 ◽  
Vol 16 (6) ◽  
pp. 987-992
Author(s):  
Yujun Zhu ◽  
Fan Zhang ◽  
Kaifang Wang ◽  
Yawen Zhang ◽  
Xiuzhi Gu ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Indoor Air ◽  
Gas Sensing ◽  
Molybdenum Trioxide ◽  
Three Dimensional ◽  
Test Results ◽  
Hierarchical Microstructure ◽  
Formaldehyde Sensing ◽  
2D Nanosheets ◽  
Sensing Characteristics

The detection of indoor formaldehyde gas is important because of its highly toxic nature. Herein, the two-dimensional α-MoO3 nanosheets and three-dimensional α-MoO3 hierarchical flowers have been prepared by simple hydrothermal strategy and used as the formaldehyde sensing materials. Their microstructures, morphologies and gas sensing characteristics towards formaldehyde were studied. The test results exhibited that, at the optimal temperature of 250 °C, the sensor performances were enhanced due to the assembly of 2D nanosheets into 3D hierarchical structure. The improved properties were contributed to the formation of the hierarchical microstructure constructed by nanosheets. The hierarchical microstructure based gas sensor has significant potential in indoor air sensing application.

TWO-DIMENSIONAL NANOSHEETS-ASSEMBLED FLOWER-LIKE Co3O4 MICROSPHERES AND THEIR GAS SENSING PERFORMANCES

NANO ◽  
2014 ◽  
Vol 09 (07) ◽  
pp. 1450071 ◽  
Author(s):  
HONGWEI CHE ◽  
AIFENG LIU ◽  
XIAOLIANG ZHANG ◽  
JUNXIAN HOU ◽  
JINGBO MU ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Gas Sensor ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Solvothermal Method ◽  
Three Dimensional ◽  
Hexadecyltrimethylammonium Bromide ◽  
Two Dimensional ◽  
2D Nanosheets ◽  
Co3o4 Microspheres

In this paper, three-dimensional (3D) Co 3 O 4 flower-like microspheres have been successfully synthesized via a facile ethylene glycol (EG)-mediated solvothermal method followed by calcination. The as-prepared flower-like precursors microspheres are formed from the assembly of 2D nanosheets in the presence of hexadecyltrimethylammonium bromide (CTAB). The flower-like architectures of the prepared precursors could be tailored by changing the amount of CTAB. Furthermore, when evaluated as a gas sensor, the obtained Co 3 O 4 flower-like microspheres exhibit a good response and sensitivity toward ethanol gas, suggesting their promising potential for gas sensors application.

A Novel Sensor Apply in Detection of Indoor Air

2020 ◽  
Vol 12 (2) ◽  
pp. 282-288 ◽  
Author(s):  
Lingling Qi ◽  
Yulun Pan
Keyword(s):  
Hydrothermal Method ◽  
Surface Area ◽  
Indoor Air ◽  
Gas Sensing ◽  
Three Dimensional ◽  
Chemical Properties ◽  
Gas Diffusion ◽  
Directional Transmission ◽  
Sensing Characteristics ◽  
And Chemical Properties

Rutile TiO2 with three dimensional structures displays excellent electrical and chemical properties. In this article, rutile TiO2 nanostructure with flower-like morphology is synthesized via a hydrothermal method without any catalyst, template, surfactant or calcination. Additionally, the effects of the reactants are discussed on the basis of controlled experiment. Interestingly, we found that the rutile TiO2 sensor show excellent gas sensing performances toward VOCs gas, primarily attributed to abundant gas diffusion channels and large gas-sensitive reaction surface area. Meanwhile, these building units promote the directional transmission of electrons, resulting in an improvement of TiO2 gas sensing characteristics.

A facile method for preparation of porous nitrogen-doped Ti Ti3C2Tx MXene for highly responsive acetone detection at high temperature

2021 ◽  
pp. 2151043
Author(s):  
Zijing Wang ◽  
Fen Wang ◽  
Angga Hermawan ◽  
Jianfeng Zhu ◽  
Shu Yin
Keyword(s):  
Gas Sensor ◽  
Recovery Time ◽  
Gas Sensing ◽  
Three Dimensional ◽  
Gas Sensitivity ◽  
Nitrogen Doped ◽  
Dimensional Network ◽  
Potential Applications ◽  
Response And Recovery ◽  
Acetone Detection

Porous nitrogen-doped Ti3C2T[Formula: see text] MXene (N-TCT) with a three-dimensional network structure is synthesized via a simple sacrifice template method and then utilized as an acetone gas sensor. By introducing nitrogen atoms as heteroatoms into Ti3C2T[Formula: see text] nanosheets, some defects generate around the doped nitrogen atoms, which can greatly improve the surface hydrophilicity and adsorption capacity of Ti3C2T[Formula: see text] Mxene nanosheets. It resulted in the enhanced gas sensitivity, achieving a response value of about 36 ([Formula: see text]/[Formula: see text] × 100%) and excellent recovery time (9s) at 150[Formula: see text]C. Compared with the pure Ti3C2T[Formula: see text]-based gas sensor (381/92s), the response and recovery time are both obviously improved, and the response value increased by 3.5 times. The gas-sensing mechanism of the porous N-TCT is also discussed in detail. Based on the excellent gas sensitivity of porous N-TCT for highly responsive acetone detection at high temperatures, the strategy of nitrogen-doped two-dimensional nanomaterials can be extended to other nanomaterials to realize their potential applications.

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.

Gas sensing characteristics of the FET-type gas sensor having inkjet-printed WS2 sensing layer

2019 ◽  
Vol 153 ◽  
pp. 27-32 ◽  
Author(s):  
Yujeong Jeong ◽  
Jongmin Shin ◽  
Yoonki Hong ◽  
Meile Wu ◽  
Seongbin Hong ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Gas Sensing ◽  
Sensing Characteristics

Fabrication of a propanol gas sensor using p-type nickel oxide nanostructures: The effect of ramping rate towards luminescence and gas sensing characteristics

2020 ◽  
Vol 253 ◽  
pp. 123316 ◽  
Author(s):  
Teboho P. Mokoena ◽  
Kenneth T. Hillie ◽  
Hendrik C. Swart ◽  
Nompumelelo Leshabane ◽  
James Tshilongo ◽  
...  
Keyword(s):  
Nickel Oxide ◽  
Gas Sensor ◽  
Gas Sensing ◽  
Oxide Nanostructures ◽  
P Type ◽  
Sensing Characteristics ◽  
Type Nickel

SYNTHESIS AND ETHANOL SENSING CHARACTERISTICS OF NANOSTRUCTURED MoO3:Zn THIN FILMS

2018 ◽  
Vol 25 (01) ◽  
pp. 1850046 ◽  
Author(s):  
SEYYED HAMID MOUSAVI-ZADEH ◽  
MOHAMMAD BAGHER RAHMANI
Keyword(s):  
Thin Films ◽  
Gas Sensing ◽  
Molybdenum Trioxide ◽  
Low Cost ◽  
Ethanol Vapor ◽  
Glass Substrates ◽  
Structure Changes ◽  
Recovery Times ◽  
Different Temperatures ◽  
Sensing Characteristics

In this research, gas sensing characteristics of undoped and zinc-doped molybdenum trioxide (MoO[Formula: see text] thin films toward ethanol vapor were investigated. Thin films were deposited using low cost and simple technique of spray pyrolysis on top of glass substrates at 450[Formula: see text]C. Effects of addition of Zn, as an impurity, on the surface morphology, structural and optical properties of MoO3 thin films were also investigated. X-ray diffraction (XRD) pattern analysis showed that by increasing the amount of impurity, crystal structure changes from orthorhombic [Formula: see text]-MoO3 to two new phases of monoclinic [Formula: see text]-ZnMoO4 and Mo5O[Formula: see text] reduced phase. Field emission scanning electron microscope (FESEM) images showed that by increasing the amount of impurity up to 5[Formula: see text]at.%, grain sizes decrease to about 60[Formula: see text]nm. UV–Vis analysis showed that by increasing the percentage of impurity the band gap of thin films increases. Gas sensing properties of samples were studied at three temperatures of 200[Formula: see text]C, 250[Formula: see text]C and 300[Formula: see text]C toward different concentrations of ethanol vapor. Gas response of 5[Formula: see text]at.% Zn-doped MoO3 thin film reached the maximum value of [Formula: see text]% when it exposed to 1000[Formula: see text]ppm of ethanol vapor. Response and recovery times for all samples were reported at different temperatures.

Enhancement of SO2 Gas Sensing Performance of Co3O4 Spinel by Cu Substitution

2020 ◽  
Vol 18 (2) ◽  
pp. 83-88
Author(s):  
P. N. Anantharamaiah ◽  
Sweta Giri
Keyword(s):  
Cobalt Oxide ◽  
Gas Sensor ◽  
Gas Sensing ◽  
Response Times ◽  
Poor Response ◽  
Potential Candidate ◽  
Potential Applicability ◽  
Co Precipitation ◽  
Gas Response ◽  
Sensing Characteristics

Single-phase spinel cobalt oxide (Co3O4) and copper-substituted cobalt oxide (Co2.8Cu0.2O4) nanomaterials were synthesized via a co-precipitation route. To explore the potential applicability of the Co3O4 and Co2.8Cu0.2O4 materials for gas sensor fabrication, their SO2 gas sensing characteristics were studied at three different temperatures using the gas concentration of 3 ppm. Unsubstituted Co3O4 sample exhibits poor response towards SO2 gas whereas the Cu-substituted sample showed superior gas sensing characteristics such as gas response, response time and recovery time at all three temperatures. Among the three studied temperatures, the maximum gas response of 7.5% was found at 200 °C with recovery and response times of 26 sec, indicating an optimal temperature. Our results demonstrate that the nanostructured Co2.8Cu0.2O4 material could be a potential candidate to design SO2 gas sensor for detection of low concentration gas.

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