scholarly journals Synthesis of Hollow ZnSnO3 Nanospheres with High Ethanol Sensing Properties

2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
Qiong Wang ◽  
Na Yao ◽  
Chen Liu ◽  
Dongmin An ◽  
Yan Li ◽  
...  
Keyword(s):  
Gas Sensing ◽  
High Sensitivity ◽  
Raw Material ◽  
X Ray Diffraction ◽  
Sensing Properties ◽  
Surface Areas ◽  
Transmission Electron ◽  
Hollow Nanostructures ◽  
Response And Recovery ◽  
Ethanol Sensing

Hollow ZnSnO3 nanospheres were synthesized by a hydrothermal method using ZnO nanospheres as the hard template and raw material simultaneously. The combined characterizations of X-ray diffraction (XRD), scanning electron microscope (SEM) and high-resolution transmission electron microscopy (HRTEM) confirmed the successful preparation of hollow ZnSnO3 nanospheres. The gas-sensing results indicated that the sensor made from hollow ZnSnO3 nanospheres exhibited high sensitivity, good selectivity, and stability to ethanol at a low operating temperature of 200°C. The sensitivity was about 32 and the response and recovery time were about 4 s and 30 s for 100 ppm ethanol, respectively. The enhancement in gas-sensing properties was attributed to the hollow nanostructures and high specific surface areas of ZnSnO3.

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

2015 ◽  
Vol 14 (04) ◽  
pp. 1550011 ◽  
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.

A Formaldehyde Gas Sensor Based on Zinc Doped Lanthanum Ferrite

2013 ◽  
Vol 873 ◽  
pp. 304-310 ◽  
Author(s):  
Jin Zhang ◽  
Yu Min Zhang ◽  
Chang Yi Hu ◽  
Zhong Qi Zhu ◽  
Qing Ju Liu
Keyword(s):  
Gas Sensing ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Sensing Properties ◽  
Transmission Electron ◽  
Lanthanum Ferrite ◽  
Gas Sensing Properties ◽  
Recovery Times ◽  
Response And Recovery ◽  
Sensing Characteristics

The gas-sensing properties of zinc doped lanthanum ferrite (Zn-LaFeO3) compounds for formaldehyde were investigated in this paper. Zn-LaFeO3 powders were prepared using sol-gel method combined with microwave chemical synthesis. The powders were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The formaldehyde gas-sensing characteristics for the sample were examined. The experimental results indicate that the sensor based on the sample Zn-LaFeO3 shows excellent gas-sensing properties to formaldehyde gas. At the optimal operating temperature of 250°C, the sensitivity of the sensor based on LaFe0.7Zn0.3O3 to 100ppm formaldehyde is 38, while to other test gases, the sensitivity is all lower than 20. The response and recovery times for the sample to formaldehyde gas are 100s and 100s, respectively.

Effect of 3.0 wt% Indium doping on ethanol sensing properties of nanocrystalline Bi2O3

2016 ◽  
Vol 12 (3) ◽  
pp. 4375-4382
Author(s):  
Dr. S D Kapse
Keyword(s):  
Bismuth Oxide ◽  
Gas Sensing ◽  
Fast Response ◽  
Nanocrystalline Powders ◽  
Material Structure ◽  
X Ray Diffraction ◽  
Sensing Properties ◽  
Transmission Electron ◽  
Ethanol Sensing ◽  
Reducing Gases

Nanocrystalline powders of pure and 3.0 wt% indium doped Bismuth oxide (Bi2O3) were prepared by ethyl alcohol mediated decomposition route. The prepared samples were then characterized in order to investigate the structural, electrical and reducing gas sensing properties of pure and In doped Bismuth oxide. X-ray diffraction (XRD) was used to confirm the material structure and transmission electron microscopy (TEM) to depict the crystallite microstructure. Bismuth oxide based thick films were expose to study the conductance response of different reducing gases such as like liquefied petroleum  (LPG), ammonia (NH3), hydrogen sulfide (H2S), and ethanol gas (C2H5OH) etc. The sensor exhibited various sensing responses to these gases at different operating temperatures. From result it is found that 3.0 wt% In-doped Bi2O3 shows the maximum response to 50 ppm ethanol at 260 0C also fast response and good recovery are the main features of investigated sensors.

Oxygen vacancies-contained SnO2 nanotubes with enhanced ethanol gas sensing properties

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040003 ◽  
Author(s):  
Yifan Chen ◽  
Xiuling Ma ◽  
Chen Li ◽  
Qiuyu Wu ◽  
Yongbo Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Performance ◽  
Oxygen Vacancies ◽  
Gas Sensing ◽  
Original Sample ◽  
X Ray Diffraction ◽  
Sensing Properties ◽  
Transmission Electron ◽  
Gas Sensing Properties ◽  
Ethanol Sensing

[Formula: see text] porous nanotubes containing oxygen vacancies were prepared by electron spinning and H plasma treatment. The morphology and crystal structure of the samples were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The ethanol-sensing properties of the [Formula: see text] sensor were tested. The results show that the samples treated with H plasma for 20 min have the best performance. Its working temperature is [Formula: see text]C lower than [Formula: see text]C of the original sample, with a sensitivity of 17 at 100 ppm, which is seven times higher than the original sample. It also shows good selectivity to some common interfering gases. This enhancement can be ascribed to the introduced oxygen vacancy. This work provides an efficient way to design high-performance gas sensor materials.

scholarly journals Synthesis of ZnO Hierarchical Structures and Their Gas Sensing Properties

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1277 ◽  
Author(s):  
Chao Fan ◽  
Fazhe Sun ◽  
Xiaomei Wang ◽  
Zuzhen Huang ◽  
Mina Keshvardoostchokami ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Gas Sensing ◽  
Zno Nanorods ◽  
Hierarchical Structures ◽  
Raw Material ◽  
Point Contacts ◽  
Sensing Properties ◽  
Transmission Electron ◽  
Zno Nanofibers ◽  
Hydrothermal Methods

Firecracker-like ZnO hierarchical structures (ZnO HS1) were synthesized by combining electrospinning with hydrothermal methods. Flower-like ZnO hierarchical structures (ZnO HS2) were prepared by a hydrothermal method using ultrasound-treated ZnO nanofibers (ZnO NFs) as raw material which has rarely been reported in previous papers. Scanning electron microscope (SEM) and transmission electron microscope’s (TEM) images clearly indicated the existence of nanoparticles on the ZnO HS2 material. Both gas sensors exhibited high selectivity toward H2S gas over various other gases at 180 °C. The ZnO HS2 gas sensor exhibited higher H2S sensitivity response (50 ppm H2S, 42.298) at 180 °C than ZnO NFs (50 ppm H2S, 9.223) and ZnO HS1 (50 ppm H2S, 17.506) gas sensors. Besides, the ZnO HS2 sensor showed a shorter response time (14 s) compared with the ZnO NFs (25 s) and ZnO HS1 (19 s) gas sensors. The formation diagram of ZnO hierarchical structures and the gas sensing mechanism were evaluated. Apart from the synergistic effect of nanoparticles and nanoflowers, more point–point contacts between flower-like ZnO nanorods were advantageous for the excellent H2S sensing properties of ZnO HS2 material.

ENHANCED GAS SENSING PROPERTIES OF p-TYPE TeO2 NANORODS FUNCTIONALIZED WITH Pd

NANO ◽  
2011 ◽  
Vol 06 (05) ◽  
pp. 455-460 ◽  
Author(s):  
HYUNSU KIM ◽  
SUNGHOON PARK ◽  
CHANGHYUN JIN ◽  
CHONGMU LEE
Keyword(s):  
Electron Microscopy ◽  
Gas Sensing ◽  
Average Diameter ◽  
Pd Nanoparticles ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Sensing Properties ◽  
Transmission Electron ◽  
Face Centered ◽  
P Type

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.

Synthesis of LiCl Doped Hollow TiO2 Nanofibers via Electrospinning and Their Humidity-Sensing Properties

2012 ◽  
Vol 476-478 ◽  
pp. 1116-1120
Author(s):  
Hui Min Huang ◽  
Jie Yu ◽  
Ce Wang
Keyword(s):  
Electron Microscopy ◽  
X Ray Diffraction ◽  
Hollow Nanofibers ◽  
Humidity Sensing ◽  
Sensing Properties ◽  
Transmission Electron ◽  
Response And Recovery ◽  
Doped Titania ◽  
The Relationship ◽  
Humidity Sensing Properties

LiCl doped titania (TiO2) hollow nanofibers were prepared by using polylactide (PLA) nanofibers as templates. The morphology and crystal structure of the TiO2hollow nanofibers were characterized by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The as-prepared LiCl doped TiO2hollow nanofibers exhibited a good humidity-sensing property. During the relative humidity (50%-95%) measurement, the response and recovery time is about 3 and 4 s, separately, with good linearity. The relationship between the humidity-sensing properties and the structure of the hollow nanofibers was also discussed. These distinguished and sensitive sensing performances make this material a good candidate in fabricating humidity sensors.

scholarly journals Gas Sensing Properties of ZnO-SnO2 Nanocomposite

2019 ◽  
Vol 32 (1) ◽  
pp. 64-68 ◽  
Author(s):  
Pushpendra Kumar ◽  
Deepak Kumar
Keyword(s):  
Gas Sensing ◽  
Rutile Phase ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Wurtzite Phase ◽  
Sensing Properties ◽  
Gas Sensing Properties ◽  
Response And Recovery ◽  
Uv Visible ◽  
Co Precipitation

In present study, ZnO-SnO2 nanocomposite was synthesized by co-precipitation method and its sensing properties with respect to carbon monoxide gas were investigated. X-ray diffraction pattern shows the exhaustive evolution of hexagonal wurtzite phase of ZnO and rutile phase of SnO2. Morphological study was done by FE-SEM and optical characterization was done by UV-visible spectrophotometer. To study the sensing properties, material was layered on conducting substrate and resistance was recorded in the presence of air and CO gas at different operating temperature. Sensing responses of pure ZnO and ZnO-SnO2 composite was also compared. ZnO-SnO2 showed much enhanced response along with better response and recovery time compared to pure ZnO.

scholarly journals An Elaborated Study of CO Sensitivities of Cu, Pt and Pd Activated SnO2 Sensors: Effect of Precipitation Agents, Dopants and Doping Methods

2017 ◽  
Author(s):  
Venkata Krishna Karthik Tangirala ◽  
Heberto Gomez-Pozos ◽  
Ventura Rodríguez-Lugo ◽  
María De La Luz Olvera
Keyword(s):  
Electron Microscopy ◽  
Gas Sensing ◽  
Atmospheric Oxygen ◽  
High Sensitivity ◽  
Cost Effective ◽  
Industrial Applications ◽  
Sno2 Nanostructures ◽  
X Ray Diffraction ◽  
Enhanced Sensitivity ◽  
Transmission Electron

In this work, we report synthesis of Cu, Pt and Pd doped SnO2 powders and their comparative CO gas sensing studies. Dopants were incorporated into SnO2 nanostructures using chemical and impregnation methods by using urea and ammonia as precipitation agents. The synthesized samples were characterized using X-ray diffraction (XRD), Raman spectroscopy, Scanning electron microscopy (SEM) and High resolution transmission electron microscopy (HR-TEM). The presence of dopants within the SnO2 nanostructures was evidenced from HR-TEM. Doped powders utilizing chemical methods with urea as precipitation agent presented higher sensitivities compared to the remaining, which is due to the formation of uniform and homogeneous particles resulted from the temperature assisted synthesis. The particle sizes of doped SnO2 nanostructures were in the range of 40-100 nm. An enhanced sensitivity around 1783 was achieved with Cu doped SnO2 when compared with two other dopants i.e., Pt (1200) and Pd: SnO2(502). The high sensitivity of Cu: SnO2 is due to formation of CuO and its excellent association and dissociation in the presence of CO with adsorbed atmospheric oxygen at sensor operation temperatures resulted in high conductance. Cu: SnO2 may be an alternative and cost effective sensor for industrial applications.

scholarly journals Synthesis by Thermal Oxidation and Gas Sensing Properties of Fe2O3 Nanorods

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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