scholarly journals CO and C3H8Sensitivity Behavior of Zinc Antimonate Prepared by a Microwave-Assisted Solution Method

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Héctor Guillen-Bonilla ◽  
Verónica-M. Rodríguez-Betancourtt ◽  
José-Trinidad Guillén-Bonilla ◽  
Juan Reyes-Gómez ◽  
Lorenzo Gildo-Ortiz ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Solution Method ◽  
High Sensitivity ◽  
Zinc Nitrate ◽  
Gas Concentration ◽  
Cell Parameters ◽  
Electron Microscopies ◽  
Microwave Assisted ◽  
Transmission Electron ◽  
Water As Solvent

ZnSb2O6has been synthesized by a microwave-assisted solution method in order to test its possible application as a gas sensor. Zinc nitrate, antimony trichloride, and ethylenediamine were used as precursors and deionized water as solvent. Microwave radiation, with a power of ~350 W, was applied for solvent evaporation. The thermal decomposition of the precursors leads to the formation of ZnSb2O6at 600°C. This oxide crystallized in a tetragonal structure with cell parametersa=4.66 Å,c=9.26 Å and space groupP42/mnm. Microwires and microrods formed by nanocrystals were observed by means of scanning and transmission electron microscopies (SEM and TEM, resp.). Pellets of the oxide were tested as gas sensors in flowing atmospheres of carbon monoxide (CO) and propane (C3H8). Sensitivity increased with the gas concentration (0–300 ppm) and working temperatures (ambient, 150 and 250°C) increase. The results indicate high sensitivity of ZnSb2O6in both gases at different concentrations and operating temperatures.

Facile Preparation of Nanocrystalline ZnO Powder for Non-Volatile Memory Application

2014 ◽  
Vol 807 ◽  
pp. 151-160
Author(s):  
A. Kathalingam ◽  
Hyun Chang Park ◽  
Sam Dong Kim ◽  
Hyun Seok Kim ◽  
T. Mahalingam
Keyword(s):  
Solution Method ◽  
Zinc Nitrate ◽  
Zno Nanoparticle ◽  
X Ray Diffraction ◽  
Chemical Route ◽  
Transmission Electron ◽  
Non Volatile Memory ◽  
Effects Of Temperature ◽  
Volatile Memory ◽  
Zno Powder

In this work, synthesis of ZnO nanoparticle by solution method and its application in non-volatile memory is reported. Nanocrystalline ZnO particles were prepared by a novel chemical route using the combination of zinc nitrate [Zn (NO3)2 6H2O] and sodium hydroxide [NaOH] at low temperature. The effects of temperature and bath concentration for the synthesis of ZnO powder have been studied. Synthesized powder was characterized by X-ray diffraction (XRD), UV-Vis spectrometer, transmission electron microscopy (TEM) and photoluminescence. Using the prepared ZnO nanoparticles with organic PMMA; non-volatile memory cells were prepared and studied its switching property.

scholarly journals Synthesis and acetone sensing properties of ZnFe2O4/rGO gas sensors

2019 ◽  
Vol 10 ◽  
pp. 2516-2526 ◽  
Author(s):  
Kaidi Wu ◽  
Yifan Luo ◽  
Ying Li ◽  
Chao Zhang
Keyword(s):  
Electron Microscopy ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Hollow Spheres ◽  
High Sensitivity ◽  
Inert Atmosphere ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Reduced Graphene

Hollow spheres of pure ZnFe2O4 and of composites of ZnFe2O4 and reduced graphene oxide (rGO) with different rGO content were prepared via a simple solvothermal method followed by a high-temperature annealing process in an inert atmosphere. The X-ray diffraction analysis confirmed that the introduction of rGO had no effect on the spinel structure of ZnFe2O4. In addition, the results of field-emission scanning electron microscopy and (high-resolution) transmission electron microscopy indicated that the synthesized samples had the structure of hollow spheres distributed uniformly onto rGO nanosheets. The diameters of the spheres were determined as about 600–1000 nm. The gas sensing test revealed that the introduction of rGO improved the performance of the sensing of acetone to low concentration, and the ZnFe2O4/rGO composite gas sensor containing 0.5 wt % of rGO exhibited a high sensitivity in sensing test using 0.8–100 ppm acetone at 200 °C. The response of the 0.5 wt % ZnFe2O4/rGO sensor to 0.8 ppm acetone was 1.50, and its response to 10 ppm acetone was 8.18, which is around 2.6 times more pronounced than the response of pure ZnFe2O4 (10 ppm, 3.20). Moreover, the sensor showed a wide linear range and good selectivity.

Three Dimensional Structure of UMo8O26: Ordering of U-Vacancies

2002 ◽  
Vol 718 ◽  
Author(s):  
N.D. Zakharov ◽  
P. Werner
Keyword(s):  
Low Temperatures ◽  
Driving Force ◽  
Three Dimensional ◽  
Solid State Reaction Method ◽  
Dimensional Structure ◽  
Unit Cell Parameters ◽  
Cell Parameters ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Edx Microanalysis

AbstractThe structure and composition of UMo8O26 synthesized by solid state reaction method have been investigated by High Resolution Transmission Electron Microscopy (HRTEM), Selected Area Electron Diffraction, and EDX microanalysis. The ordering of U vacancies results in considerable enlargement of unit cell parameters: an=6.44 nm, bn=1.45 nm, cn=1.6 nm. It is build up of four layers piled up in c direction. Each following layer is shifted relative to previous one by vector bn/4. Eight hexagonal tunnels in each layer are filled by U atoms, while the eight others are vacant (V). Interaction between U cations and vacancies is driving force for ordering. The variation of stoichiometry can be a reason for appearance of incommensurate modulations in these crystals. It seems plausible that this structure might also exhibit superconductivity at low temperatures.

scholarly journals V2O3/C composite fabricated by carboxylic acid-assisted sol–gel synthesis as anode material for lithium-ion batteries

2021 ◽  
Author(s):  
G. S. Zakharova ◽  
E. Thauer ◽  
A. N. Enyashin ◽  
L. F. Deeg ◽  
Q. Zhu ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Lithium Ion Batteries ◽  
Sol Gel ◽  
Carbon Sources ◽  
Lithium Ion ◽  
X Ray Diffraction ◽  
Electron Microscopies ◽  
Transmission Electron ◽  
Battery Electrode ◽  
Sol Gel Synthesis

AbstractThe potential battery electrode material V2O3/C has been prepared using a sol–gel thermolysis technique, employing vanadyl hydroxide as precursor and different organic acids as both chelating agents and carbon sources. Composition and morphology of resultant materials were characterized by X-ray diffraction, Raman spectroscopy, scanning and transmission electron microscopies, physical sorption, and elemental analysis. Stability and electronic properties of model composites with chemically and physically integrated carbon were studied by means of quantum-chemical calculations. All fabricated composites are hierarchically structured and consist of carbon-covered microparticles assembled of polyhedral V2O3 nanograins with intrusions of amorphous carbon at the grain boundaries. Such V2O3/C phase separation is thermodynamically favored while formation of vanadium (oxy)carbides or heavily doped V2O3 is highly unlikely. When used as anode for lithium-ion batteries, the nanocomposite V2O3/C fabricated with citric acid exhibits superior electrochemical performance with an excellent cycle stability and a specific charge capacity of 335 mAh g−1 in cycle 95 at 100 mA g−1. We also find that the used carbon source has only minor effects on the materials’ electrochemical performance.

scholarly journals Microwave-Assisted Combustion Synthesis of ZnO Nanoparticles

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
M. Kooti ◽  
A. Naghdi Sedeh
Keyword(s):  
Electron Microscopy ◽  
Zno Nanoparticles ◽  
Combustion Method ◽  
Zinc Nitrate ◽  
High Yield ◽  
Fast Method ◽  
Simple Method ◽  
X Ray ◽  
Microwave Assisted ◽  
Average Size

A new and simple method was applied for the synthesis of ZnO nanoparticles with an average size of 20 nm. In this microwave-assisted combustion method, glycine as a fuel and zinc nitrate as precursor were used. The final product was obtained very fast with high yield and purity. The synthesized nanoscale ZnO was characterized by X-ray Diffraction (XRD), Energy Dispersive X-ray spectroscopy (EDX), and Fourier transform infrared spectroscopy (FT-IR). The size and morphology of the ZnO nanoparticles have been determined by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) techniques. This is a simple and fast method for the preparation of ZnO nanoparticles with no need for expensive materials or complicated treatments.

scholarly journals Direct Production of a Novel Iron-Based Nanocomposite from the Laser Pyrolysis ofFe(CO)5/MMAMixtures: Structural and Sensing Properties

2010 ◽  
Vol 2010 ◽  
pp. 1-12 ◽  
Author(s):  
R. Alexandrescu ◽  
I. Morjan ◽  
A. Tomescu ◽  
C. E. Simion ◽  
M. Scarisoreanu ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Gas Sensors ◽  
High Sensitivity ◽  
X Ray Diffraction ◽  
Direct Production ◽  
X Ray ◽  
Metallic Particles ◽  
Ir Laser ◽  
Iron Iron ◽  
Optimum Working

Iron/iron oxide-based nanocomposites were prepared by IR laser sensitized pyrolysis ofFe(CO)5and methyl methacrylate (MMA) mixtures. The morphology of nanopowder analyzed by TEM indicated that mainly core-shell structures were obtained. X-ray diffraction techniques evidence the cores as formed mainly by iron/iron oxide crystalline phases. A partially degraded (carbonized) polymeric matrix is suggested for the coverage of the metallic particles. The nanocomposite structure at the variation of the laser density and of the MMA flow was studied. The new materials prepared as thick films were tested for their potential for acting as gas sensors. The temporal variation of the electrical resistance in presence ofNO2, CO, andCO2, in dry and humid air was recorded. Preliminary results show that the samples obtained at higher laser power density exhibit rather high sensitivity towardsNO2detection andNO2selectivity relatively to CO andCO2. An optimum working temperature of200°Cwas found.

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.

Rapid synthesis of Ag2Se dendrites with enhanced electrical performance by microwave-assisted solution method

2013 ◽  
Vol 37 (2) ◽  
pp. 323-328 ◽  
Author(s):  
Jian Pei ◽  
Gang Chen ◽  
Dechang Jia ◽  
Rencheng Jin ◽  
Haiming Xu ◽  
...  
Keyword(s):  
Solution Method ◽  
Electrical Performance ◽  
Rapid Synthesis ◽  
Microwave Assisted

Physical Simulation of Weldability of Weldox 1300 Steel

2013 ◽  
Vol 762 ◽  
pp. 551-555 ◽  
Author(s):  
Marek Stanislaw Węglowski ◽  
Marian Zeman ◽  
Miroslaw Lomozik
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Physical Simulation ◽  
High Strength ◽  
Parent Material ◽  
Cooling Time ◽  
Electron Microscopies ◽  
Transmission Electron ◽  
Transformation Diagrams ◽  
The Impact

In the present study, the investigation of weldability of new ultra-high strength - Weldox 1300 steel has been presented. The thermal simulated samples were used to investigate the effect of welding cooling time t8/5 on the microstructure and mechanical properties of the heat affected zone (HAZ). In the frame of these investigation the microstructure was studied by the light (LM) and transmission electron microscopies (TEM). It has been shown that the microstructure of the Weldox 1300 steel is composed of tempered martensite, and inside the laths the minor precipitations mainly V(CN) and molybdenum carbide Mo2C were observed. Mechanical properties of parent material were analysed by the tensile, impact and hardness tests. In details the influence of cooling time in the range of 2,5 - 300 s. on hardness, impact toughness and microstructure of simulated HAZ was studied by using welding thermal simulation test. The results show that the impact toughness and hardness decrease with the increase of t8/5 under the condition of a single thermal cycle in simulated HAZ. The continuous cooling transformation diagrams (CCT-W for welding conditions) of Weldox 1300 steel for welding purposes was also elaborated. The steel Weldox 1300 for cooling time in the range of 2,5 - 4 s showed martensite microstructure, for time from 4 s to 60 s mixture of martensite and bainite, and for longer cooling time mixture of ferrite, bainite and martensite. The results indicated that the weldability of Weldox 1300 steel is limited and to avoid the cold cracking the preheating procedure or medium net linear heat input should be used.

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