scholarly journals C2H5OH and LPG sensing properties of -Fe2O3 microflowers prepared by hydrothermal route

2016 ◽  
Vol 19 (3) ◽  
pp. 108-116
Author(s):  
Phuoc Huu Luong ◽  
Tho Duc Do ◽  
Dien Dac Nguyen ◽  
Hien Xuan Vu ◽  
Vuong Duc Dang

The flower-like micron-structure of α-Fe2O3 was synthesized via hydrothermal treatment at 140 C for 24 h using Fe(NO3)3.9H2O and Na2SO4 as the precursors. A thin film constructed by the as-prepared material was created by spin coating technique. The structure, morphology, and composition of the samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM). The α-Fe2O3 microflowers (MFs) with average diameter of several micrometers are assembled of nanorods which possess average diameter and length of 40 nm and hundred nm, respectively. The gas sensing properties of α-Fe2O3 film were tested with ethanol (C2H5OH) and liquefied petroleum gas (LPG) at the operating temperatures of 225–400 °C. The sensor response of the α-Fe2O3 film reached highest sensitivity to C2H5OH and LPG at 275 C and 350 °C, respectively. The thin film exhibited higher sensitivity and lower working temperature to C2H5OH than those to LPG. The film can detect minimum concentration of 250 ppm C2H5OH. The response time of the film to C2H5OH is approximately 30 s.

NANO ◽  
2011 ◽  
Vol 06 (05) ◽  
pp. 455-460 ◽  
Author(s):  
HYUNSU KIM ◽  
SUNGHOON PARK ◽  
CHANGHYUN JIN ◽  
CHONGMU LEE

TeO2 nanorods functionalized with Pd were prepared by a three-step process comprising thermal evaporation of Te powders, Pd deposition by photo-reduction, and annealing. Sensors were fabricated by using the Pd -functionalized TeO2 nanorods. Scanning electron microscopy images exhibited that the nanorods with diameters in a range of 50–100 nm and lengths of a few micrometers were covered with the Pd nanoparticles with an average diameter of ~ 15 nm. Transmission electron microscopy and X-ray diffraction analysis revealed that the nanorods were monocrystalline simple tetragonal TeO2 . On the other hand, the nanoparticles on them were confirmed to be nanocrystalline face-centered cubic Pd . The multiple-networked TeO2 nanorod sensors exhibited a sensitivity of 3.13% at 100 ppm NO2 at 300°C, whereas the Pd -functionalized TeO2 nanorod sensors exhibited a sensitivity of 11.97% under the same condition. The recovery time of TeO2 nanorods was decreased considerably at every NO2 concentration by the Pd -functionalization even if the response time decreased or increased slightly depending upon the NO2 concentration. In addition, the origin of the enhancement of the sensing properties of the TeO2 nanorods by functionalization with Pd is discussed.


OUSL Journal ◽  
2016 ◽  
Vol 10 (0) ◽  
pp. 59 ◽  
Author(s):  
K. N. D. Bandara ◽  
K. M. D. C. Jayathileka ◽  
M. S. Gunewardene ◽  
D. P. Dissanayake ◽  
J. K. D. S. Jayanetti

2015 ◽  
Vol 14 (04) ◽  
pp. 1550011 ◽  
Author(s):  
A. Sharma ◽  
M. Tomar ◽  
V. Gupta ◽  
A. Badola ◽  
N. Goswami

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.


Author(s):  
A. Wisitsoraat ◽  
A. Tuantranont ◽  
E. Comini ◽  
G. Sberveglieri ◽  
W. Wlodarski

2016 ◽  
Vol 371 ◽  
pp. 224-230 ◽  
Author(s):  
U.T. Nakate ◽  
R.N. Bulakhe ◽  
C.D. Lokhande ◽  
S.N. Kale

2019 ◽  
Vol 19 (11) ◽  
pp. 7083-7088 ◽  
Author(s):  
Nan Zhang ◽  
Xiaohui Ma ◽  
Shengping Ruan ◽  
Yanyang Yin ◽  
Chuannan Li ◽  
...  

In this study, CdS nanowires (NWs)/Ag nanoparticle materials (CdS@Ag) with Schottky junction were synthesized by a simple process. The Ag nanoparticles with a diameter of 3–10 nm were uniformly scattered on the surface of CdS NWs with an average diameter of 30 nm. The gas sensing properties and the effect of Ag content and relative humidity on the ethanol sensing properties of CdS NWs were investigated in detail. When the relative humidity was below 60% RH, the sensor, especially the one based on [email protected], exhibited an enhanced ethanol sensing response and selectivity compared with that of pristine CdS NWs, which was believed that Ag catalyzed the reaction between ionized oxygen species and ethanol. However, excessive Ag content does not mean a higher response and even decreased the response. Also, the stability of CdS NWs and CdS@Ag NWs was also investigated, which were almost stable for four months.


1999 ◽  
Vol 146 (9) ◽  
pp. 3536-3537 ◽  
Author(s):  
P. H. Wei ◽  
G. B. Li ◽  
S. Y. Zhao ◽  
L. R. Chen

2016 ◽  
Vol 16 (4) ◽  
pp. 4029-4034 ◽  
Author(s):  
Chunxia Liu ◽  
Lixia Yang ◽  
Dan Yue ◽  
Mengnan Wang ◽  
Lin Jin ◽  
...  

Rare earth ions (Tb3+, Eu3+) doped CaWO4 microstructures were synthesized by a facile hydrothermal route without using any templates and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) spectrum. The results indicate that the asprepared samples are well crystallized with scheelite structure of CaWO4, and the average diameter of the microstructures is 2∼4 μm. The morphology of CaWO4:Eu3+ microstructures can be controllably changed from microspheres to microflowers through altering the doping concentration of Eu3+ from 3% to 35%, and the microflowers are constructed by a number of CaWO4:Eu3+ nanoflakes. Under the excitation of UV light, the emission spectrum of CaWO4:Eu3+ is composed of the characteristics emission of Eu3+ 5D0-7FJ (J = 1, 2, 3, 4) transitions, and that of CaWO4:Tb3+ is composed of Tb3+ 5D4-7FJ (J = 6, 5, 4, 3) transitions. Both of the optimal doping concentrations of Tb3+ and Eu3+ in CaWO4 microstructures are about 5%.


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