scholarly journals Characterization of Flexible Multi-Walled Carbon Nanotubes Network Sensor to Freon Gas Detection

2021 ◽  
pp. 2543-2554
Author(s):  
Nisreen M. Al-Makram ◽  
Wasan R. Saleh
Keyword(s):  
Room Temperature ◽  
Filter Cake ◽  
Operating Temperature ◽  
X Ray ◽  
Before And After ◽  
Recovery Times ◽  
Multi Walled Carbon Nanotubes ◽  
Response And Recovery ◽  
Walled Carbon Nanotubes

     MWCNTs-OH was used to prepare a flexible gas sensor by deposition as a network on a filter cake using the method of filtration from suspension (FFS). The morphological and structural properties of the MWCNTs network were characterized before and after exposure to Freon gas using FTIR spectra and X-ray diffractometer, which confirmed that the characteristics of the sensor did not change after exposure to the gas. The sensor was exposed to a pure Freon134a gas as well as to a mixture of Freon gas and air with different ratios at room temperature. The experiments showed that the sensor works at room temperature and the sensitivity values increased with increasing operating temperature, to be 58% until 150 ºC. The fabricated flexible sensor has good response and recovery times at low gas concentrations of 1.3, 2, and 2.7 ppm.

Fabrication of TiO2 sensor using rapid breakdown anodization method to measure pressure, humidity and sense gases at room temperature

2019 ◽  
pp. 1694-1703
Author(s):  
Reem Saadi Khaleel ◽  
Mustafa Shakir Hashim
Keyword(s):  
Room Temperature ◽  
Average Pressure ◽  
Spherical Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Recovery Times ◽  
Sensitivity And Selectivity ◽  
Response And Recovery ◽  
Anodization Method ◽  
Rapid Breakdown Anodization

Rapid breakdown anodization (RBA) process was used to fabricate TiO2 sensor to measure pressure and humidity and sense gases at room temperature. This chemical process transformed Ti to its oxide (TiO2) as a powder with amorphous phase as X ray diffraction (XRD) technique confirmed.  This oxide consisted from semi spherical nanoparticles and titania nanotubes (TNTs) as Scanning electron microscope (SEM) technique showed.  TiO2 powder was deposited on Ti substrates by using electrophoretic deposition (EPD) method.   Average pressure sensitivity was 0.34 MΩ/bar and hysteresis area was 1.4 MΩ .bar. Resistance of TiO2 decreased exponentially with the increasing of relative humidity (RH%). The sensitivity% of TiO2 for RH% was greater than 70% in the range of (50-95). TiO2 was tested as a sensor for Ammonia, Ethanol and Methanol. Its sensitivity and selectivity towards Ammonia were the greatest but the shortest response and recovery times were recorded toward Methanol.

scholarly journals Synthesis of ZnO-CuO flower-like hetero-nanostructures as volatile organic compounds (VOCs) sensor at room temperature

2018 ◽  
Vol 36 (3) ◽  
pp. 452-459
Author(s):  
Raad S. Sabry ◽  
Roonak Abdul Salam A. Alkareem
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Room Temperature ◽  
Dip Coating ◽  
X Ray Diffraction ◽  
X Ray ◽  
Volatile Organic ◽  
Recovery Times ◽  
Coating Methods ◽  
Response And Recovery

AbstractZnO-CuO flower-like hetero-nanostructures were successfully prepared by combining hydrothermal and dip coating methods. Flower-like hetero-nanostructures of ZnO-CuO were examined by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and UV-Vis. The sensing properties of ZnO-CuO flower-like hetero-nanostructures to volatile organic compounds (VOCs) were evaluated in a chamber containing acetone or isopropanol gas at room temperature. The sensitivity of ZnO-CuO flower-like hetero-nanostructures to VOCs was enhanced compared to that of pure leafage-like ZnO nanostructures. Response and recovery times were about 5 s and 6 s to 50 ppm acetone, and 10 s and 8 s to 50 ppm isopropanol, respectively. The sensing performance of ZnO-CuO flower-like hetero-nanostructures was attributed to the addition of CuO that led to formation of p-n junctions at the interface between the CuO and ZnO. In addition, the sensing mechanism was briefly discussed.

Acetylene Sensing by ZnO/TiO2 Nanoparticles

2020 ◽  
Vol 15 (1) ◽  
pp. 41-45 ◽  
Author(s):  
Zhi-Cheng Zhong ◽  
Zhao-Jun Jing ◽  
Kui-Yuan Liu ◽  
Tong Liu
Keyword(s):  
Gas Sensors ◽  
Operating Temperature ◽  
Sol Gel ◽  
Fast Response ◽  
X Ray Diffraction ◽  
Uniform Size ◽  
X Ray ◽  
Recovery Times ◽  
Response And Recovery ◽  
Hydrothermal Methods

We adopted the sol–gel and hydrothermal methods to prepare the TiO2 nanomaterials doped with ZnO. We adopted X-ray diffraction, scanning electron microscopy, and the Brunauer–Emmett–Teller method to investigate the materials’ structures and morphologies. The results showed that the prepared TiO2 nanomaterials had uniform size and good dispersibility. Gas sensors were fabricated and their performances in acetylene sensing were assessed. The results show that the sensor prepared with the ZnO/TiO2 nanomaterial doped with 10 wt% ZnO gave fast response and recovery times for acetylene gas at different concentrations. When the operating temperature was 280 °C, the gas sensor detected 200 ppm acetylene gas with a response sensitivity of 9.9, a response time of 5 s, and a recovery time of 2 s.

scholarly journals Room temperature carbon nanotube based sensor for carbon monoxide detection

2014 ◽  
Vol 3 (2) ◽  
pp. 349-354 ◽  
Author(s):  
A. Hannon ◽  
Y. Lu ◽  
J. Li ◽  
M. Meyyappan
Keyword(s):  
Carbon Monoxide ◽  
Room Temperature ◽  
Potential Candidate ◽  
Electrode Structure ◽  
Recovery Times ◽  
Response And Recovery ◽  
Good Repeatability ◽  
Repeatability And Reproducibility ◽  
Carbon Monoxide Detection ◽  
Walled Carbon Nanotubes

Abstract. Sulfonated single-walled carbon nanotubes have been used in an integrated electrode structure for the detection of carbon monoxide. The sensor responds to 0.5 ppm of CO in air at room temperature. All eight sensors with this material in a 32-sensor array showed good repeatability and reproducibility, with response and recovery times of about 10 s. Pristine nanotubes generally do not respond to carbon monoxide and the results here confirm sulfonated nanotubes to be a potential candidate for the construction of an electronic nose that requires at least a few materials for the selective detection of CO.

Structural and Acetone Sensing Properties of La-Doped Porous In2O3 Nanospheres by Hydrothermal Synthesis

2014 ◽  
Vol 1053 ◽  
pp. 177-180
Author(s):  
Dan Han ◽  
Peng Song ◽  
Qi Wang ◽  
Hui Hui Zhang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Operating Temperature ◽  
X Ray Diffraction ◽  
Acetone Concentration ◽  
X Ray ◽  
Recovery Times ◽  
Response And Recovery ◽  
La Doped ◽  
Scanning Electron

The La-doped porous In2O3 nanospheres were prepared by a simple hydrothermal method, and La3+ accounted for 3 mol% of the In3+. The La exists and has been doped in the lattice of In2O3 characterized respectively by the means of energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD), the morphology of the samples with uniform nanospheres observed by field-emission scanning electron microscopy (FESEM). Moreover, the sensor exhibits higher response properties compared with pure porous In2O3 nanospheres towards different acetone concentration at operating temperature 300 °C. The response and recovery times is about 13 s and 8 s to 50 ppm acetone.

Multi-Walled Carbon Nanotubes Functionalized with Carboxyl and Amide for Acetone detection at Room Temperature

2021 ◽  
Vol 317 ◽  
pp. 195-201
Author(s):  
Nurjahirah Janudin ◽  
Norli Abdullah ◽  
Faizah Md Yasin ◽  
Mohd Hanif Yaacob ◽  
Muhammad Zamharir Ahmad ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Response Time ◽  
Recovery Time ◽  
Room Temperature ◽  
Functional Group ◽  
Compositional Analysis ◽  
X Ray ◽  
Multi Walled Carbon Nanotubes ◽  
Acetone Detection ◽  
Walled Carbon Nanotubes

The functionalization of multi-walled carbon nanotubes (CNT) with amide group is reported as an alternative to enhance response time, recovery time and sensitivity of detecting acetone gas. We have fabricated an interdigitated transducer (IDT) deposited with amide-functionalized CNT. The elemental compositional analysis was characterized using Energy Dispersion X-ray spectroscopy and CHNOS elemental analyzer. The detection of acetone gas was performed in room temperature and digital multimeter was employed to record the changes of resistivity of IDT upon exposure of acetone. Results showed that amide functional group increases sensitivity, shortens the response time as well as recovery time of the sensor.

scholarly journals Chemical Synthesis, Functionalization and Characterization of Multiwalled Carbon Nanotubes

2020 ◽  
Vol 6 (3) ◽  
pp. 905-907
Author(s):  
S.S. Gautam ◽  
G.P. Satsangi ◽  
V.R. Satsangi
Keyword(s):  
Carbon Nanotubes ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Functionalized Mwcnts

This research work is attempted to synthesize, functionalize and to characterize multi walled carbon nanotubes (MWCNTs). The synthesis of multi walled carbon nanotubes was done by chemical vapor deposition (CVD) method. The characterization of MWCNTs was done by adopting the following techniques such as field emission scanning electron microscope, X-ray diffraction, Fourier-transform infrared spectroscopy. The crystalline quality of MWCNTs was confirmed from the analysis of X-ray diffraction pattern. FE-SEM image obtained for MWCNTs and functionalized MWCNTs and it has been seen that dimeter of most of the MWCNTs lies around 90 nm, where as, functionalized MWCNTs diameter is smaller i.e., around 35 nm only. Fourier-transform infrared spectroscopy study confirmed the presence of –COOH and H- bonded –OH in functionalized MWCNTs.

scholarly journals Preparation, Characterization, and Mechanistic Understanding of Pd-Decorated ZnO Nanowires for Ethanol Sensing

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Xiao Deng ◽  
Shengbo Sang ◽  
Pengwei Li ◽  
Gang Li ◽  
Fanqin Gao ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Operating Temperature ◽  
Zno Nanowires ◽  
X Ray Diffraction ◽  
X Ray ◽  
Recovery Times ◽  
Response And Recovery ◽  
New Perspective ◽  
Ethanol Sensing ◽  
Higher Sensitivity

ZnO nanowires (ZnO-NWs) and Pd-decorated ZnO nanowires (Pd-ZnO-NWs) were prepared by hydrothermal growth and characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). When used for gas sensing, both types of nanowires showed a good selectivity to ethanol but a higher sensitivity and lower operating temperature were found with Pd-ZnO-NWs sensors comparing to those of ZnO-NWs sensor. When exposed to 200 ppm ethanol, our ZnO-NWs sensor showed a sensitivity of about 2.69 at 425°C whereas 1.3 at. % Pd-ZnO-NWs sensor provided a 57% more detection sensibility at 325°C. In addition, both response and recovery times of Pd-ZnO-NWs sensors were significantly reduced (9 s) comparing to the ZnO-NWs. Finally, Pd-ZnO-NWs sensor also showed a much lower detection limit of about 1 ppm. The sensing mechanism of Pd-ZnO-NWs sensors has also been clarified, thereby providing a new perspective for further improvement of the sensing performance of ethanol sensors.

Development and Characterization of Novel Conductive Nanofiller Based on Multi-Walled Carbon Nanotubes Grafted with Poly(3,4-Ethylenedioxythiophene)

2018 ◽  
Vol 762 ◽  
pp. 203-208
Author(s):  
Guna Vugule ◽  
Ingars Reinholds ◽  
Janis Zicans ◽  
Remo Merijs Meri ◽  
Kaspars Ozols
Keyword(s):  
Carbon Nanotubes ◽  
Graft Polymerization ◽  
Oxidative Polymerization ◽  
Powder Materials ◽  
Gravimetric Analysis ◽  
X Ray ◽  
Multi Walled Carbon Nanotubes ◽  
Characteristic Signal ◽  
Walled Carbon Nanotubes

In the present study, an approach for the graft polymerization of multi-walled carbon nanotubes (MWCNTs) with 3,4-ethylenedioxythiophene (EDOT) has been evaluated. The surface of the MWCNTs was activated with thiophene groups through the amide linker followed by oxidative polymerization of EDOT monomer resulted in the development of PEDOT-g-MWCNTs. The methods of thermal gravimetric analysis (TGA), X-ray fluorescence, and Raman spectroscopy were used for characterization of functionalization efficiency. The TGA data indicated of 21% functionalization attached to MWCNTs. X-ray fluorescence confirmed the presence of Cl, and S atoms in functionalized fillers. The study of Raman spectra confirmed the presence of PEDOT groups attributed to most characteristic signal at 1400-1500 cm-1 region. The electrical conductivity for both pristine MWCNT and PEDOT-g-MWCNT powder materials was compared.

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