Schottky diodes based on 2D materials for environmental gas monitoring: a review on emerging trends, recent developments and future perspectives

Using zinc chloride solution and ammonia (25%) as raw material, with the presence of surfactant (CTAB), the microrod ZnO material was synthesized by the hydrothermal method. The phase composition and microstructure of the prepared ZnO material were characterized with XRD and SEM. The results show that the ZnO material possesses a high degree of crystallization, its diameter below 4 μm, and its length about 35 μm. The gas sensing property of gas sensor fabricated with the prepared ZnO material was evaluated via the static volumetric method. At the operating temperature of 200°C, the gas sensor has high sensitivity and selectivity to CH3COCH3.The gas sensing characterization was also discussed.

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Synthesis by Thermal Oxidation and Gas Sensing Properties of Fe2O3 Nanorods

JST: Engineering and Technology for Sustainable Development ◽

10.51316/jst.149.etsd.2021.31.2.14 ◽

2021 ◽

Vol 31.2 (149) ◽

pp. 84-88

Keyword(s):

Thermal Oxidation ◽

Gas Sensing ◽

High Sensitivity ◽

Measuring System ◽

X Ray Diffraction ◽

X Ray ◽

Sensing Properties ◽

Oxide Nanorods ◽

Gas Sensing Properties ◽

Sensitivity And Selectivity

Iron oxide nanorods were synthesized by thermal oxidation of iron foil in the air at 300-500 oC. The scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to investigate the crystal structures and morphologies properties of the Fe2O3 nanorods. The gas sensing properties of the Fe2O3 nanorods were investigated using a static-gas measuring system in a range of 300-500 oC with the target gases of C2H5OH, CH3COCH3, LPG, and NH3. The results show that Fe2O3 nanorods possess high sensitivity and selectivity toward CH3COCH3. The highest response of 19 was recorded with 1000 ppm CH3COCH3 at the operating temperature of 400 oC.

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Polyaniline/SnO2 Nanocomposite Sensor for NO2 Gas Sensing at Low Operating Temperature

International Journal of Nanoscience ◽

10.1142/s0219581x15500118 ◽

2015 ◽

Vol 14 (04) ◽

pp. 1550011 ◽

Cited By ~ 8

Author(s):

A. Sharma ◽

M. Tomar ◽

V. Gupta ◽

A. Badola ◽

N. Goswami

Keyword(s):

Thin Films ◽

Gas Sensing ◽

High Sensitivity ◽

Morphological Properties ◽

X Ray Diffraction ◽

Chemical Route ◽

Sensing Properties ◽

Response Recovery ◽

Transmission Electron ◽

Gas Sensing Properties

In this paper gas sensing properties of 0.5–3% polyaniline (PAni) doped SnO 2 thin films sensors prepared by chemical route have been studied towards the trace level detection of NO 2 gas. The structural, optical and surface morphological properties of the PAni doped SnO 2 thin films were investigated by performing X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Raman spectroscopy measurements. A good correlation has been identified between the microstructural and gas sensing properties of these prepared sensors. Out of these films, 1% PAni doped SnO 2 sensor showed high sensitivity towards NO 2 gas along with a sensitivity of 3.01 × 102 at 40°C for 10 ppm of gas. On exposure to NO 2 gas, resistance of all sensors increased to a large extent, even greater than three orders of magnitude. These changes in resistance upon removal of NO 2 gas are found to be reversible in nature and the prepared composite film sensors showed good sensitivity with relatively faster response/recovery speeds.

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Fabrication of Transition-metal (Zn, Mn, Cu)-based MOFs as Efficient Sensor Materials for Detection of H2 Gas by Clad Modified Fiber Optic Gas Sensor Technique

10.21203/rs.3.rs-250500/v1 ◽

2021 ◽

Author(s):

M Nagoor Meeran ◽

S.P. Saravanan ◽

H.H Hegazy

Keyword(s):

Transition Metal ◽

Fiber Optic ◽

Gas Sensing ◽

High Sensitivity ◽

Long Term Stability ◽

Sensing Material ◽

Sensor Technique ◽

Recent Developments ◽

Metal Organic ◽

Elevated Surface

Abstract Recent research demonstrate that promising gas sensing materials are called metal-organic structures (MOFs) and their products due to their tunable form, elevated surface area, and extremely porous structure and physisorption towards gases with relatively low temperature.In this report, recent developments in transition-metal (Zn, Mn, Cu)-based MOFs and their derivatives are synthesized as sensing materials. The sensors samples were analyzed by XRD, SEM, TEM, BET and XPS in order to know the textural, structural and electronic state of the samples. Fiber optic clad modified sensors were fabricated and tested gas sensing properties towards H2 gas with various concentrations (0-1000 ppm). Among the three sensing material, Zn doped MOFs sensor showed outstanding selectivity with high sensitivity (115 counts/kpa) towards H2 gas. Moreover, it has shown high response (20 s) and recovery time (27 s) as well as long term stability. The designed sensors may be required to apply to the production of an outstanding sensor for H2 for commercial uses.

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Preparation of Nanostructured SnO2-NiO Composite Semiconductor for Gas Sensor Applications

International Journal of Advanced Research in Science, Communication and Technology ◽

10.48175/ijarsct-2134 ◽

2021 ◽

pp. 391-403

Author(s):

S. Kumar ◽

P. Gowthaman ◽

J. Deenathayalan

Keyword(s):

Gas Sensor ◽

Composite Nanofibers ◽

Volume Fraction ◽

Gas Sensing ◽

Precipitation Method ◽

Response Sensitivity ◽

X Ray ◽

Sensing Properties ◽

Working Temperature ◽

Gas Sensing Properties

Electro spinning technology combined with chemical precipitation method and high-temperature calcination was used to prepare SnO2-NiO composite semiconductor nanofibers with different Sn content. Scanning electron microscope (SEM), X-ray diffractometer (XRD) and energy dispersive X-ray spectrometer (EDS) were used to characterize the morphology, structure and content of various elements of the sample. Using ethanol as the target gas, the gas sensing properties of SnO2-NiO nanofibers and the influence of Sn content on the gas sensing properties of composite nanofibers were explored. The research results show that SnO2-NiO composite nanofibers have a three-dimensional network structure, and the SnO2 composite can significantly enhance the gas sensitivity of NiO nanofibers. With increase of SnO2 content, the response sensitivity of composite fibers to ethanol gas increases, and the response sensitivity of composite nanofibers with the highest response to ethanol gas with a volume fraction of 100×10-6 at the optimal working temperature of 160℃ are13.4;It is 8.38 times the maximum response sensitivity of NiO nanofibers. Compared with the common ethanol gas sensor MQ-3 on the market, SnO2-NiO composite nanofibers have a lower optimal working temperature and higher response sensitivity, which has certain practical application value

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Preparation and Gas-Sensing Property of Coppertetra-Iso-Propoxyphthalocyanine Spin-Coating Film

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.197-198.1735 ◽

2011 ◽

Vol 197-198 ◽

pp. 1735-1738

Author(s):

Qiang Li ◽

Li Hua Huo ◽

Shan Gao ◽

Xiao Juan Qi ◽

Hui Zhao

Keyword(s):

Thin Films ◽

Spin Coating ◽

Gas Sensing ◽

High Sensitivity ◽

Coating Film ◽

Gas Sensing Properties ◽

Response And Recovery ◽

Ft Ir ◽

Spinning Speed ◽

Spectroscopy Property

The thin films of copper 2, 9, 16, 23-tetra-iso-propoxy phthalocyanine (i-pro-CuPc) were prepared by spin-coating technique. The surface morphology and spectroscopy property of the thin films were characterized by AFM, UV-Vis and FT-IR spectra. The results show that good films can be obtained under certain spinning speed. The gas-sensing properties of the multilayers to three alcohols gas were measured at room temperature. The spin-coating thin films exhibited high sensitivity and rapid response- recovery characteristics to these gases. The response and recovery time of the thin films to 30*10-6 v/v of C2H5OH vapor is only 28 s and 55 s, respectively.

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

Nanomaterials ◽

10.3390/nano10040785 ◽

2020 ◽

Vol 10 (4) ◽

pp. 785 ◽

Cited By ~ 24

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.

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

Journal of Chemistry ◽

10.1155/2015/382087 ◽

2015 ◽

Vol 2015 ◽

pp. 1-7 ◽

Cited By ~ 4

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.

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