CO Sensing Properties of La1-xCaxFeO3 Perovskite Nanocrystalline Materials

2011 ◽  
Vol 495 ◽  
pp. 323-326 ◽  
Author(s):  
Ming Zhao ◽  
Li Hui Sun ◽  
Ji Fan Hu ◽  
Hong Wei Qin
Keyword(s):  
Response Time ◽  
Nanocrystalline Materials ◽  
Recovery Time ◽  
Operating Temperature ◽  
Sol Gel ◽  
Nanocrystalline Powders ◽  
Orthorhombic Structure ◽  
Gel Method ◽  
Sensing Properties ◽  
Sol Gel Method

The La1-xCaxFeO3 nanocrystalline powders were prepared by sol-gel method. These powders crystallized as perovskite orthorhombic structure. With an increase of Ca content, the resistance of La1-xCaxFeO3 sensors in air decreases at first, undergoes a minimum at x=0.3, and then increases again. La1-xCaxFeO3-based sensors show sensitive responses to CO. Among those La1-xCaxFeO3-based sensors, the sensor with x=0.2 shows the highest response to 200 ppm CO at operating temperatures below 325°C. The highest response S=(RCO-Rair)/RCO for the La0.8Ca0.2FeO3 based sensor to 200 ppm CO is 87% with response time 15 s and recovery time 60 s at an operating temperature of 100°C.

Gas Sensing Properties of Nanocrystalline Nd1-xCaxFeO3

2011 ◽  
Vol 495 ◽  
pp. 327-330
Author(s):  
Xiang Wei Kong ◽  
Hong Wei Qin ◽  
Ling Zhang ◽  
Li Hui Sun ◽  
Ji Fan Hu
Keyword(s):  
Grain Size ◽  
Gas Sensing ◽  
Sol Gel ◽  
Nanocrystalline Powders ◽  
Orthorhombic Structure ◽  
Gel Method ◽  
Sensing Properties ◽  
Mean Grain Size ◽  
Gas Sensing Properties ◽  
The Mean

The nanocrystalline powders Nd1-xCaxFeO3 prepared by sol-gel method crystallized as perovskite orthorhombic structure. The mean grain size of Nd1-xCaxFeO3 powders were about 15~ 40 nm. The conductivity of the Ca doped samples was enhanced, compared to that of the undoped. The Nd0.9Ca0.1FeO3-based sensor showed good gas sensing properties to ethanol and acetone. The responses of the Nd0.9Ca0.1FeO3-based sensor to 600ppm ethanol and acetone were about 158.4 at 220°C and 61.7 at 240°C, respectively.

H2S Gas Sensor Based on SnO2 and CuO Nanoparticles

2015 ◽  
Vol 1 (2) ◽  
pp. 21-26 ◽  
Author(s):  
Mohammad Hossein Sarfi ◽  
Mohammad Ghadimi ◽  
Arash Babaee
Keyword(s):  
Response Time ◽  
Recovery Time ◽  
Oil And Gas ◽  
Sol Gel ◽  
Oil And Gas Industry ◽  
Xrd Analysis ◽  
Thin Layers ◽  
Gel Method ◽  
Sol Gel Method ◽  
Environment Temperature

Hydrogen Sulfide (H2S) is a toxic gas that has adverse effects on human health as well as the oil and gas industry; hence, it is important to identify its characteristics appropriately. The present research was aimed to study the sensing behavior of SnO2-CuO thin layers obtained by the sol-gel method. The working temperature in the present investigation was the environment temperature and the resistance curves related to the sensing behavior were obtained. The microstructure of the covered layers was studied using Field Emission Scanning Electron Microscope (FE-SEM), AFM and XRD analysis method. The thin layer of SnO2-CuO optimized with sensory characteristics was coated using sol-gel method and were heated for 5 hours at 400 °C. The best response number was 1180 (no unit), the response time was 43 seconds and the least recovery time was 210 seconds. Moreover, it had a longer response time compared to the unheated sample, but the response number and the recovery time were improved due to the thermal treatment.

Enhanced photoelectric responses induced by visible light of acetone gas sensors based on CuO-ZnO nanocomposites at about room temperature

Sensor Review ◽  
2018 ◽  
Vol 38 (3) ◽  
pp. 311-320 ◽  
Author(s):  
Yuxin Miao ◽  
Guofeng Pan ◽  
Caixuan Sun ◽  
Ping He ◽  
Guanlong Cao ◽  
...  
Keyword(s):  
Visible Light ◽  
Gas Sensors ◽  
Zno Nanoparticles ◽  
Room Temperature ◽  
Operating Temperature ◽  
Sol Gel ◽  
Content Type ◽  
Gel Method ◽  
Sensing Properties ◽  
Sol Gel Method

PurposeThe purpose of this paper is to study the effect of doping, annealing temperature and visible optical excitation on CuO-ZnO nanocomposites’ acetone sensing properties and introduce an attractive candidate for acetone detection at about room temperature.Design/methodology/approachZnO nanoparticles doped with CuO were prepared by sol-gel method, and the structure and morphology were characterized via X-ray diffraction, scanning electron microscope, energy dispersive spectroscopy and Brunauer-Emmett-Teller. The photoelectric responses of CuO-ZnO nanocomposites to cetone under the irradiation of visible light were investigated at about 30°C. The photoelectric response mechanism was also discussed with the model of double Schottky.FindingsThe doping of CuO enhanced performance of ZnO nanoparticles in terms of the photoelectric responses and the gas response and selectivity to acetone of ZnO nanoparticles, in addition, decreasing the operating temperature to about 30ºC. The optimum performance was obtained by 4.17% CuO-ZnO nanocomposites. Even at the operating temperature, about 30ºC, the response to 1,000 ppm acetone was significantly increased to 579.24 under the visible light irradiation.Practical implicationsThe sensor fabricated by 4.17% CuO-ZnO nanocomposites exhibited excellent acetone-sensing characteristics at about 30ºC. It is promising to be applied in low power and miniature acetone gas sensors.Originality/valueIn the present research, a new nanocomposite material of CuO-ZnO was prepared by Sol-gel method. The optimum gas sensing properties to acetone were obtained by 4.17% CuO-ZnO nanocomposites at about 30ºC operating temperature when it was irradiated by visible light with the wavelength more than 420 nm.

scholarly journals Synthesis and Characterization of Nanocrystalline ZnO Doped with Al3+ and Ni2+ by a Sol–Gel Method Coupled with Ultrasound Irradiation

Crystals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 406 ◽  
Author(s):  
M. Robles-Águila ◽  
J. Luna-López ◽  
Álvaro Hernández de la Luz ◽  
J. Martínez-Juárez ◽  
M. Rabanal
Keyword(s):  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Ultrasound Irradiation ◽  
Morphological Properties ◽  
Nanocrystalline Powders ◽  
Metallic Ions ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Doped Zno

Zinc oxide is one of the most important semiconducting metal oxides and one of the most promising n-type materials, but its practical use is limited because of both its high thermal conductivity and its low electrical conductivity. Numerous studies have shown that doping with metals in ZnO structures leads to the modification of the band gap energy. In this work, Al-doped ZnO, Ni-doped ZnO, and undoped ZnO nanocrystalline powders were prepared by a sol–gel method coupled with ultrasound irradiation, and the results show the influence of Al3+ and Ni2+ ions in the ZnO network. The doping concentrations in ZnO of 0.99 atom % for ZnO–Al and 0.80 atom % for ZnO–Ni were obtained by X-ray Fluorescence (XRF). X-ray Diffraction (XRD) and Raman Spectroscopy showed a decreased intensity and broadening of main peaks, indicating metallic ions. The crystallite size of the sample was decreased from 24.5 nm (ZnO) to 22.0 nm (ZnO–Al) and 21 nm (ZnO–Ni). The textural and morphological properties were analyzed via Nitrogen Adsorption (BET method) and Field Emission Scanning Electron Microscopy (FESEM).

CONTROLLED SYNTHESIS AND CHARACTERIZATION OF TiO2 NANOPARTICLES VIA A SOL–GEL METHOD

2004 ◽  
Vol 03 (06) ◽  
pp. 749-755 ◽  
Author(s):  
YING LI ◽  
SUO HON LIM ◽  
TIM WHITE
Keyword(s):  
Sol Gel ◽  
Critical Role ◽  
Rietveld Analysis ◽  
Nanocrystalline Powders ◽  
X Ray Diffraction ◽  
Gelation Temperature ◽  
Gel Method ◽  
Sol Gel Method ◽  
Transmission Electron

The properties influencing the photocatalytic activity of TiO 2 particles have been suggested to include the surface area, crystallinity, crystallite size and crystal structure. Therefore, manipulation of the microstructure of titania, especially of nanocrystalline powders, is very important in the preparative process. In this study, nanocrystalline TiO 2 powders with controlled particle size and phase composition were synthesized at low temperature (<80°C) by a modified sol–gel method. The effects of gelation temperature were systematically investigated. It was found that this parameter played a critical role in determining the crystallinity of single phase anatase. With increasing gelation temperature, the crystallinity of anatase improved initially and then decreased if the temperature was raised to 80°C. These nanomaterials were characterized comprehensively by powder X-ray diffraction (including Rietveld analysis), high-resolution transmission electron microscopy, DSC/TGA thermal analysis and UV–Vis spectrometry.

Gas Sensing Properties of Nanocrystalline Indium Oxide Synthesized by Sol–Gel Method

2012 ◽  
Vol 5 (1) ◽  
pp. 109-113 ◽  
Author(s):  
S. C. Kulkarni ◽  
C. S. Aher ◽  
R. Y. Borse ◽  
B. G. Bharate ◽  
SalemS. Al-Deyab ◽  
...  
Keyword(s):  
Indium Oxide ◽  
Gas Sensing ◽  
Sol Gel ◽  
Gel Method ◽  
Sensing Properties ◽  
Sol Gel Method ◽  
Gas Sensing Properties

A Non-Alkoxide Sol−Gel Method for the Preparation of Homogeneous Nanocrystalline Powders of La0.85Sr0.15MnO3

2006 ◽  
Vol 18 (7) ◽  
pp. 1928-1937 ◽  
Author(s):  
Christopher N. Chervin ◽  
Brady J. Clapsaddle ◽  
Hsiang Wei Chiu ◽  
Alexander E. Gash ◽  
Joe H. Satcher, ◽  
...  
Keyword(s):  
Sol Gel ◽  
Nanocrystalline Powders ◽  
Gel Method ◽  
Sol Gel Method

Thermal, optical and gas sensing properties of ZnO films prepared by different techniques

2018 ◽  
Vol 81 (1) ◽  
pp. 10101 ◽  
Author(s):  
Sonik Bhatia ◽  
Neha Verma ◽  
Munish Aggarwal
Keyword(s):  
Gas Sensor ◽  
Recovery Time ◽  
Gas Sensing ◽  
Operating Temperature ◽  
Sol Gel ◽  
Hexagonal Wurtzite Structure ◽  
Effect Of Temperature ◽  
Zno Films ◽  
Sensing Properties ◽  
Response And Recovery

Nowadays, for environmental protection, the use of portable gas sensor is essential to detect toxic gases. To control this problem of hazardous gases, metal oxide based sensors plays a vital role. In this recent study, Indium (2 at.wt.%) doped ZnO films has been prepared by sol gel spin coating and thermal evaporation techniques on glass substrates. To enhance the sensing properties, indium (In) was used as dopant and their annealing effect of temperature was observed. Thermal properties have shown the fruitful result that prepared films are useful for the fabrication of solar cell. Electrical properties revealed that capacitance and dielectric constant decreases with increase in frequency. X-ray Diffraction showed hexagonal wurtzite structure highly oriented along (1 0 1) plane. Field emission scanning electron microscope of these synthesis films prepared by different have shown the morphology as nanospheres having size of the order of 40–60 nm. 2.0 at.% of indium as modifier resulted in highest response and selectivity towards 5 ppm of NO2 gas at different operating temperature (50–200 °C). Highest sensitivity was obtained at operating temperature of 150 °C. Prepared films have quick response and recovery time in the range of 14–27 s and 67–63 s. The highest response and recovery time of gas sensor was explained by valence ion mechanism.

Gas-sensing properties of nanostructured TiO2–xZrO2 thin films obtained by the sol–gel method

2019 ◽  
Vol 92 (2) ◽  
pp. 415-426 ◽  
Author(s):  
Artem S. Mokrushin ◽  
Elizaveta P. Simonenko ◽  
Nikolay P. Simonenko ◽  
Kirill A. Bukunov ◽  
Philipp Yu. Gorobtsov ◽  
...  
Keyword(s):  
Thin Films ◽  
Gas Sensing ◽  
Sol Gel ◽  
Gel Method ◽  
Nanostructured Tio2 ◽  
Sensing Properties ◽  
Sol Gel Method ◽  
Gas Sensing Properties
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