scholarly journals Improved Sensitivity of α-Fe2O3 Nanoparticle-Decorated ZnO Nanowire Gas Sensor for CO

Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1903 ◽  
Author(s):  
Jeongseok Lee ◽  
Se-Hyeong Lee ◽  
So-Young Bak ◽  
Yoojong Kim ◽  
Kyoungwan Woo ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Indium Tin Oxide ◽  
Gas Sensing ◽  
Sol Gel ◽  
Oxide Semiconductor ◽  
Oxide Glass ◽  
Optimum Operating ◽  
Optimum Operating Temperature ◽  
X Ray ◽  
Fe2o3 Nanoparticle

A strategy for improving the sensitivity of a sensor for detecting CO and NH3 gases is presented herein. The gas sensor was fabricated from ZnO metal oxide semiconductor nanostructures grown via a vapor–liquid–solid process and decorated with α-Fe2O3 nanoparticles via a sol–gel process. The response was enhanced by the formation of an α-Fe2O3/ZnO n–n heterojunction and the growth of thinner wires. ZnO nanowires were grown on indium–tin–oxide glass electrodes using Sn as a catalyst for growth instead of Au. The structure and elemental composition were investigated using field-emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction. The gas sensing results indicate that the response value to 100 ppm CO was 18.8 at the optimum operating temperature of 300 °C.

scholarly journals Decoration of CuO NWs Gas Sensor with ZnO NPs for Improving NO2 Sensing Characteristics

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 2103 ◽  
Author(s):  
Tae-Hee Han ◽  
So-Young Bak ◽  
Sangwoo Kim ◽  
Se Hyeong Lee ◽  
Ye-Ji Han ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Gas Sensors ◽  
Sol Gel ◽  
Oxide Semiconductor ◽  
Zno Nps ◽  
X Ray ◽  
Semiconductor Gas Sensor ◽  
Initial Resistance ◽  
P Type ◽  
Sensing Characteristics

This paper introduces a method for improving the sensitivity to NO2 gas of a p-type metal oxide semiconductor gas sensor. The gas sensor was fabricated using CuO nanowires (NWs) grown through thermal oxidation and decorated with ZnO nanoparticles (NPs) using a sol-gel method. The CuO gas sensor with a ZnO heterojunction exhibited better sensitivity to NO2 gas than the pristine CuO gas sensor. The heterojunction in CuO/ZnO gas sensors caused a decrease in the width of the hole accumulation layer (HAL) and an increase in the initial resistance. The possibility to influence the width of the HAL helped improve the NO2 sensing characteristics of the gas sensor. The growth morphology, atomic composition, and crystal structure of the gas sensors were analyzed using field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy, and X-ray diffraction, respectively.

TUNGSTEN-DOPED TiO2 NANOLAYERS WITH IMPROVED CO2 GAS SENSING PROPERTIES FOR ENVIRONMENTAL APPLICATIONS

2017 ◽  
Vol 24 (Supp02) ◽  
pp. 1850024 ◽  
Author(s):  
MALIHEH SABERI ◽  
ALI AKBAR ASHKARRAN
Keyword(s):  
Electron Microscopy ◽  
Gas Sensing ◽  
Operating Temperature ◽  
Sol Gel ◽  
Optimum Operating ◽  
Optimum Operating Temperature ◽  
Sensing Properties ◽  
Vis Spectroscopy ◽  
Gas Sensing Properties ◽  
Tungsten Concentration

Tungsten-doped TiO2 gas sensors were successfully synthesized using sol–gel process and spin coating technique. The fabricated sensor was characterized by field emission scanning electron microscopy (FE-SEM), ultraviolet visible (UV–Vis) spectroscopy, transmission electron microscopy (TEM), X-Ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Gas sensing properties of pristine and tungsten-doped TiO2 nanolayers (NLs) were probed by detection of CO2 gas. A series of experiments were conducted in order to find the optimum operating temperature of the prepared sensors and also the optimum value of tungsten concentration in TiO2 matrix. It was found that introducing tungsten into the TiO2 matrix enhanced the gas sensing performance. The maximum response was found to be (1.37) for 0.001[Formula: see text]g tungsten-doped TiO2 NLs at 200[Formula: see text]C as an optimum operating temperature.

scholarly journals A Hydrogen Gas Sensor Based on TiO2 Nanoparticles on Alumina Substrate

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2483 ◽  
Author(s):  
Siti Mohd Chachuli ◽  
Mohd Hamidon ◽  
Md. Mamat ◽  
Mehmet Ertugrul ◽  
Nor Abdullah
Keyword(s):  
Tio2 Nanoparticles ◽  
Gas Sensor ◽  
Operating Temperature ◽  
Hydrogen Gas ◽  
Optimum Operating ◽  
Optimum Operating Temperature ◽  
X Ray ◽  
Semiconductor Gas Sensor ◽  
Sensing Material ◽  
P Type

High demand of semiconductor gas sensor works at low operating temperature to as low as 100 °C has led to the fabrication of gas sensor based on TiO2 nanoparticles. A sensing film of gas sensor was prepared by mixing the sensing material, TiO2 (P25) and glass powder, and B2O3 with organic binder. The sensing film was annealed at temperature of 500 °C in 30 min. The morphological and structural properties of the sensing film were characterized by field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). The gas sensor was exposed to hydrogen with concentration of 100–1000 ppm and was tested at different operating temperatures which are 100 °C, 200 °C, and 300 °C to find the optimum operating temperature for producing the highest sensitivity. The gas sensor exhibited p-type conductivity based on decreased current when exposed to hydrogen. The gas sensor showed capability in sensing low concentration of hydrogen to as low as 100 ppm at 100 °C.

A comparative study of doped and un-doped sol-gel TiO2 and P25 TiO2 (photo)electrodes

2007 ◽  
Vol 55 (12) ◽  
pp. 153-160 ◽  
Author(s):  
Y. Pooarporn ◽  
A. Worayingyong ◽  
M. Wörner ◽  
P. Songsiriritthigul ◽  
A.M. Braun
Keyword(s):  
Indium Tin Oxide ◽  
Electrochemical Impedance ◽  
Anatase Phase ◽  
Sol Gel ◽  
Oxide Glass ◽  
Electrochemical Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Titanium Dioxide Films ◽  
Indium Tin Oxide Glass

Doped and undoped titanium dioxide films have been deposited on indium tin oxide glass using the sol-gel technique. The percentage of rutile in the prepared TiO2, calcined at 823 K and determined by X-ray diffraction, was 23% compared to 24% of rutile in P25-TiO2. Cerium doped TiO2 showed mainly the anatase phase, as characterised by both X-ray diffraction and Raman spectroscopy. The electrochemical and photoelectrochemical properties of the films were studied by cyclic voltammetry and electrochemical impedance spectroscopy. The (photo)electrochemical characteristics of the different films are reported and discussed.

SnO2 Nanofibers Gas Sensor Detecting H2 Dissolved in Transformer Oil

2013 ◽  
Vol 706-708 ◽  
pp. 1008-1011
Author(s):  
Shu Di Peng ◽  
Gao Lin Wu ◽  
Qian Wang
Keyword(s):  
Gas Sensor ◽  
Gas Sensing ◽  
Power Transformer ◽  
Synthesis Method ◽  
Transformer Oil ◽  
Optimum Operating ◽  
Optimum Operating Temperature ◽  
Fault Gas ◽  
Response And Recovery ◽  
Hydrothermal Approach

Hydrogen is an effective fault gas dissolved in transformer oil, and online monitoring its concentration has important meaning on condition assessment and fault diagnosis of power transformer. A facile and simple synthesis method of ultra-sensitive SnO2nanofibers through a hydrothermal approach was reported. The crystalline phases and microstructures were performed by X-ray powder diffraction and field-emission scanning electron microscopy. The gas sensor based on prepared SnO2 nanofibers was fabricated by a side-heated preparation, and its gas sensing performances to H2were measured. The fabricated sensor exhibits excellent sensing properties to H2, such as low optimum operating temperature, high gas response, rapid response and recovery time, good stability and repeatability.

Sunflower-Like Zinc Oxide Architectures: The Application of Acetone Gas Sensor for Asphalt Pavement Construction

2021 ◽  
Vol 16 (1) ◽  
pp. 6-10
Author(s):  
Bo Zuo ◽  
Yan Fu ◽  
Gaofeng Deng ◽  
Lingling Qi
Keyword(s):  
Gas Sensor ◽  
Gas Sensing ◽  
Operating Temperature ◽  
Asphalt Pavement ◽  
Optimum Operating ◽  
Optimum Operating Temperature ◽  
Measurement Results ◽  
Gas Sensing Properties ◽  
Pavement Construction ◽  
Gas Response

In this work, hierarchical nanorod-assembled ZnO sunflower-like structures were successfully synthesized through a water bath route. Crystalline phase and surface morphology of as-prepared ZnO were investigated via XRD and SEM techniques, respectively. Gas sensor fabricated from nanorod-assembled ZnO sunflowers was made, which exhibits excellent gas sensing properties at various concentrations of acetone and different operating temperatures. The gas response values at the optimum operating temperature (300 °C) are 49 towards 200 ppm acetone. The sensing measurement results indicates that the as-synthesized ZnO material may depict potential application as an acetone detector in asphalt pavement construction.

ITO Thin Films on Silicon Buffer by Sol Gel Method

2006 ◽  
Vol 514-516 ◽  
pp. 1155-1160 ◽  
Author(s):  
Talaat Moussa Hammad
Keyword(s):  
Thin Films ◽  
Indium Tin Oxide ◽  
Optical Transmission ◽  
Sol Gel ◽  
Precursor Solution ◽  
Charge Carriers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ito Thin Films ◽  
Uv Visible

Sol gel indium tin oxide thin films (In: Sn = 90:10) were prepared by the sol-gel dipcoating process on silicon buffer substrate. The precursor solution was prepared by mixing SnCl2.2H2O and InCl3 dissolved in ethanol and acetic acid. The crystalline structure and grain orientation of ITO films were determined by X-ray diffraction. The surface morphology of the films was characterized by scanning electron microscope (SEM). Optical transmission and reflectance spectra of the films were analyzed by using a UV-visible spectrophotometer. The transport properties of majority charge carriers for these films were studied by Hall measurement. ITO thin film with electrical resistivity of 7.6 ×10-3 3.cm, Hall mobility of approximately 2 cm2(Vs)-1 and free carrier concentration of approximately 4.2 ×1020 cm-3 are obtained for films 100 nm thick films. The I-V curve measurement showed typical I-V characteristic behavior of sol gel ITO thin films.

scholarly journals Titanium Dioxide-Based64∘YXLiNbO3Surface Acoustic Wave Hydrogen Gas Sensors

2008 ◽  
Vol 2008 ◽  
pp. 1-5 ◽  
Author(s):  
A. Z. Sadek ◽  
D. Buso ◽  
A. Martucci ◽  
P. Mulvaney ◽  
W. Wlodarski ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Acoustic Wave ◽  
Gas Sensors ◽  
Sol Gel ◽  
Hydrogen Gas ◽  
Optimum Operating ◽  
Optimum Operating Temperature ◽  
Helium Atmosphere ◽  
Gas Detectors ◽  
Hydrogen Gas Sensors

Amorphous titanium dioxide (TiO2) and gold (Au) dopedTiO2-based surface acoustic wave (SAW) sensors have been investigated as hydrogen gas detectors. The nanocrystal-dopedTiO2films were synthesized through a sol-gel route, mixing a Ti-butoxide-based solution with diluted colloidal gold nanoparticles. The films were deposited via spin coating onto64∘YXLiNbO3SAW transducers in a helium atmosphere. The SAW gas sensors were operated at various temperatures between 150 and310∘C. It was found that gold doping onTiO2increased the device sensitivity and reduced the optimum operating temperature.

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

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

Xylene-sensing of Fe2(MoO4)3 nanoplates prepared via a hydrothermal method

2017 ◽  
Vol 10 (03) ◽  
pp. 1750022 ◽  
Author(s):  
Mengying Xu ◽  
Zhidong Lin ◽  
Wenying Guo ◽  
Yuyuan Hong ◽  
Ping Fu ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Gas Sensing ◽  
Operating Temperature ◽  
Hydrothermal Process ◽  
Optimum Operating ◽  
Average Crystalline Size ◽  
Optimum Operating Temperature ◽  
Recovery Times ◽  
Response And Recovery ◽  
Simple Hydrothermal Process

Fe2(MoO4)3 nanoplates were prepared via a simple hydrothermal process. The average crystalline size of these nanoplates is 85.8[Formula: see text]nm. The sensor based on Fe2(MoO4)3 shows a high gas sensing performance to xylene. The response of Fe2(MoO4)3 sensor is 25.9–100[Formula: see text]ppm xylene at optimum operating temperature of 340[Formula: see text]C. The response and recovery times to 100[Formula: see text]ppm xylene are 4 and 10[Formula: see text]s, respectively. Furthermore, the Fe2(MoO4)3 sensor exhibits remarkable selectivity detection of xylene gas with negligible responses to toluene and benzene. Therefore, the Fe2(MoO4)3 is a promising material for the detection of xylene gas sensors.

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