scholarly journals Facile Synthesis, Microstructure, and Gas Sensing Properties of NdCoO3 Nanoparticles

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Lorenzo Gildo-Ortiz ◽  
Héctor Guillén-Bonilla ◽  
Juan Reyes-Gómez ◽  
Verónica María Rodríguez-Betancourtt ◽  
M. de la L. Olvera-Amador ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Cobalt Nitrate ◽  
Diffusional Growth ◽  
Orthorhombic Crystal ◽  
Cell Parameters ◽  
Standard Atmosphere ◽  
Sensing Applications ◽  
Water As Solvent ◽  
Different Temperatures ◽  
Precursor Powders

NdCoO3 nanoparticles were successfully synthesized by a simple, inexpensive, and reproducible solution method for gas sensing applications. Cobalt nitrate, neodymium nitrate, and ethylenediamine were used as precursors and distilled water as solvent. The solvent was evaporated later by means of noncontinuous microwave radiation at 290 W. The obtained precursor powders were calcined at 200, 500, 600, and 700°C in a standard atmosphere. The oxide crystallized in an orthorhombic crystal system with space group Pnma (62) and cell parameters a=5.33 Å, b=7.52 Å, and c=5.34 Å. The nanoparticles showed a diffusional growth to form a network-like structure and porous adsorption configuration. Pellets prepared from NdCoO3 were tested as gas sensors in atmospheres of carbon monoxide and propane at different temperatures. The oxide nanoparticles were clearly sensitive to changes in gas concentrations (0–300 ppm). The sensitivity increased with increasing concentration of the gases and operating temperatures (25, 100, 200, and 300°C).

scholarly journals Gas Sensing Properties of NiSb2O6 Micro- and Nanoparticles in Propane and Carbon Monoxide Atmospheres

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Verónica-M. Rodríguez-Betancourtt ◽  
Héctor Guillén Bonilla ◽  
Martín Flores Martínez ◽  
Alex Guillén Bonilla ◽  
J. P. Moran Lazaro ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Monoxide ◽  
Gas Sensing ◽  
Average Diameter ◽  
Cell Parameters ◽  
Sensing Applications ◽  
Transmission Electron ◽  
Colloidal Method ◽  
Antimony Chloride ◽  
20 Nm

Micro- and nanoparticles of NiSb2O6 were synthesized by the microwave-assisted colloidal method. Nickel nitrate, antimony chloride, ethylenediamine, and ethyl alcohol were used. The oxide was obtained at 600°C and was analyzed by X-ray diffraction (XRD) and Raman spectroscopy, showing a trirutile-type structure with cell parameters a = 4.641 Å, c = 9.223 Å, and a space group P42/mnm (136). Average crystal size was estimated at ~31.19 nm, according to the XRD-peaks. The microstructure was scrutinized by scanning electron microscopy (SEM), observing microrods measuring ~3.32 μm long and ~2.71 μm wide, and microspheres with an average diameter of ~8 μm; the size of the particles shaping the microspheres was measured in the range of ~0.22 to 1.8 μm. Transmission electron microscopy (TEM) revealed that nanoparticles were obtained with sizes in the range of 2 to 20 nm (~10.7 nm on average). Pellets made of oxide’s powders were tested in propane (C3H8) and carbon monoxide (CO) atmospheres at different concentrations and temperatures. The response of the material increased significantly as the temperature and the concentration of the test gases rose. These results show that NiSb2O6 may be a good candidate for gas sensing applications.

High Temperature Phases of Nanostructured Tungsten Oxide for Gas Sensing Applications

2006 ◽  
Vol 915 ◽  
Author(s):  
Andrea Ponzoni ◽  
Elisabetta Comini ◽  
Matteo Ferroni ◽  
Guido Faglia ◽  
Giorgio Sberveglieri
Keyword(s):  
High Temperature ◽  
Tungsten Oxide ◽  
Phase Stability ◽  
Thermal Evaporation ◽  
Gas Sensing ◽  
Grain Coarsening ◽  
Crystallinity Degree ◽  
Sensing Applications ◽  
Different Temperatures ◽  
Annealing Effects

AbstractWO3 layers have been synthesized by thermal evaporation at high temperature in order to induce the crystallization of stable films. Phase stability has been proved by annealing treatments carried out at different temperatures. Annealing effects on gas sensing performances have been explained in terms of crystallinity degree and grain coarsening phenomena.

scholarly journals Tri-doped Co-annealed Zinc Oxide Semi-conductor Synthesis and Characterization - Photodegradation of Dyes and Gas sensing Applications

2021 ◽  
Author(s):  
Manik Rakhra ◽  
Neha Verma
Keyword(s):  
Zno Nanoparticles ◽  
Gas Sensing ◽  
Combustion Method ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
Fast Reaction ◽  
Nitrogen Gas ◽  
Sensing Applications ◽  
Different Temperatures

Abstract Despite the fact that much of the research has been performed on ZnO-based nanoparticles but still a lot of unexplored The synthesis and characterization of the ZnO Nano rinds, which have been co-created using a simple combustion method, are documented here and are prepared with its sensor and photocatalytic degradations. In, Sn and SB specific quantity was used as dopants, while their effects were co-annealed on glass substrate at different temperatures, i.e. 1.0 percent and 1.5 percent at 5000C, 11000. At varying temperatures, the samples were coated on to the chosen substrate using doctor blade technique. Crystallite scale was measured to the range of 30-50 nm. At such temperatures the grain size measured for the samples was in range of 50-70 nm. This showed that the prepared Nano rods are well crystalline and have strong optical properties to handle. Studies of X ray diffraction showed the influential point (101). These coated samples designed for nitrogen gas sensing have been tested for the development of smart and functional instruments. Furthermore it was observed that the samples prepared at higher temperatures exhibit better recovery and better reaction time. Valance ion process explains the gas sensors fast reaction and long recovery time. Thus prepared ZnO nanoparticles are have photocattalytic degredation (99.86%) only in 55 min. We observed optimum exposure at an operating temperature of 1050C. It is notable that morphology of susceptible layer nanoparticles is preserved based on different tri-doping concentrations. The concentration of T2-ZnO nanoparticles for photodegradation of the DR-31 dye and NO2 gas sensing applications were 1.0 at.wt%

Effect of Grain Size on Strain in a Copper Oxide Nanofilm for Gas Sensing Applications

2019 ◽  
Vol 11 (5) ◽  
pp. 05040-1-05040-4
Author(s):  
Sumanta Kumar Tripathy ◽  
◽  
Sanjay Kumar ◽  
Divya Aparna Narava ◽  
◽  
...  
Keyword(s):  
Grain Size ◽  
Copper Oxide ◽  
Gas Sensing ◽  
Sensing Applications

scholarly journals Optimization of a Low-Power Chemoresistive Gas Sensor: Predictive Thermal Modelling and Mechanical Failure Analysis

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 783 ◽  
Author(s):  
Andrea Gaiardo ◽  
David Novel ◽  
Elia Scattolo ◽  
Michele Crivellari ◽  
Antonino Picciotto ◽  
...  
Keyword(s):  
Low Power ◽  
Failure Analysis ◽  
Gas Sensors ◽  
High Performance ◽  
Gas Sensing ◽  
Mechanical Failure ◽  
Sensing Applications ◽  
Theoretical Approaches ◽  
Sensing Material ◽  
Silicon Bulk

The substrate plays a key role in chemoresistive gas sensors. It acts as mechanical support for the sensing material, hosts the heating element and, also, aids the sensing material in signal transduction. In recent years, a significant improvement in the substrate production process has been achieved, thanks to the advances in micro- and nanofabrication for micro-electro-mechanical system (MEMS) technologies. In addition, the use of innovative materials and smaller low-power consumption silicon microheaters led to the development of high-performance gas sensors. Various heater layouts were investigated to optimize the temperature distribution on the membrane, and a suspended membrane configuration was exploited to avoid heat loss by conduction through the silicon bulk. However, there is a lack of comprehensive studies focused on predictive models for the optimization of the thermal and mechanical properties of a microheater. In this work, three microheater layouts in three membrane sizes were developed using the microfabrication process. The performance of these devices was evaluated to predict their thermal and mechanical behaviors by using both experimental and theoretical approaches. Finally, a statistical method was employed to cross-correlate the thermal predictive model and the mechanical failure analysis, aiming at microheater design optimization for gas-sensing applications.

scholarly journals Advanced development of metal oxide nanomaterials for H2 gas sensing applications

2021 ◽  
Author(s):  
Yushu Shi ◽  
Huiyan Xu ◽  
Tongyao Liu ◽  
Shah Zeb ◽  
Yong Nie ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Gas Sensors ◽  
Gas Sensing ◽  
The Past ◽  
Sensing Applications ◽  
The Future ◽  
Metal Oxide Nanomaterials ◽  
Nanomaterials Synthesis ◽  
Advanced Development

The scheme of the structure of this review includes an introduction from the metal oxide nanomaterials’ synthesis to application in H2 gas sensors—a vision from the past to the future.

scholarly journals Transforming Pt-SnO2 Nanoparticles into Pt-SnO2 Composite Nanoceramics for Room-Temperature Hydrogen-Sensing Applications

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2123
Author(s):  
Ming Liu ◽  
Caochuang Wang ◽  
Pengcheng Li ◽  
Liang Cheng ◽  
Yongming Hu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Sintering Temperature ◽  
Sno2 Nanoparticles ◽  
Hydrogen Sensing ◽  
Sensing Applications ◽  
Nanostructured Metal Oxides ◽  
Low Dimensional ◽  
Sensing Characteristics ◽  
Nanostructured Metal

Many low-dimensional nanostructured metal oxides (MOXs) with impressive room-temperature gas-sensing characteristics have been synthesized, yet transforming them into relatively robust bulk materials has been quite neglected. Pt-decorated SnO2 nanoparticles with 0.25–2.5 wt% Pt were prepared, and highly attractive room-temperature hydrogen-sensing characteristics were observed for them all through pressing them into pellets. Some pressed pellets were further sintered over a wide temperature range of 600–1200 °C. Though the room-temperature hydrogen-sensing characteristics were greatly degraded in many samples after sintering, those samples with 0.25 wt% Pt and sintered at 800 °C exhibited impressive room-temperature hydrogen-sensing characteristics comparable to those of their counterparts of as-pressed pellets. The variation of room-temperature hydrogen-sensing characteristics among the samples was explained by the facts that the connectivity between SnO2 grains increases with increasing sintering temperature, and Pt promotes oxidation of SnO2 at high temperatures. These results clearly demonstrate that some low-dimensional MOX nanocrystals can be successfully transformed into bulk MOXs with improved robustness and comparable room-temperature gas-sensing characteristics.

scholarly journals Allanite at high temperature: effect of REE on the thermal behaviour of epidote-group minerals

2021 ◽  
Vol 48 (9) ◽  
Author(s):  
G. Diego Gatta ◽  
Francesco Pagliaro ◽  
Paolo Lotti ◽  
Alessandro Guastoni ◽  
Laura Cañadillas-Delgado ◽  
...  
Keyword(s):  
Cell Volume ◽  
Thermal Behaviour ◽  
Unit Cell Volume ◽  
Unit Cell ◽  
Atomic Scale ◽  
Elastic Behaviour ◽  
Positive Trend ◽  
Cell Parameters ◽  
Thermal Anisotropy ◽  
Different Temperatures

AbstractThe thermal behaviour of a natural allanite-(Ce) has been investigated up to 1073 K (at room pressure) by means of in situ synchrotron powder X-ray diffraction and single-crystal neutron diffraction. Allanite preserves its crystallinity up to 1073 K. However, up to 700 K, the thermal behaviour along the three principal crystallographic axes, of the monoclinic β angle and of the unit-cell volume follow monotonically increasing trends, which are almost linear. At T > 700–800 K, a drastic change takes place: an inversion of the trend is observed along the a and b axes (more pronounced along b) and for the monoclinic β angle; in contrast, an anomalous increase of the expansion is observed along the c axis, which controls the positive trend experienced by the unit-cell volume at T > 700–800 K. Data collected back to room T, after the HT experiments, show unit-cell parameters significantly different with respect to those previously measured at 293 K: allanite responds with an ideal elastic behaviour up to 700 K, and at T > 700–800 K its behaviour deviates from the elasticity field. The thermo-elastic behaviour up to 700 K was modelled with a modified Holland–Powell EoS; for the unit-cell volume, we obtained the following parameters: VT0 = 467.33(6) Å3 and αT0(V) = 2.8(3) × 10–5 K−1. The thermal anisotropy, derived on the basis of the axial expansion along the three main crystallographic directions, is the following: αT0(a):αT0(b):αT0(c) = 1.08:1:1.36. The T-induced mechanisms, at the atomic scale, are described on the basis of the neutron structure refinements at different temperatures. Evidence of dehydroxylation effect at T ≥ 848 K are reported. A comparison between the thermal behaviour of allanite, epidote and clinozoisite is carried out.

scholarly journals Recent Advances in ZnO-Based Carbon Monoxide Sensors: Role of Doping

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4425
Author(s):  
Ana María Pineda-Reyes ◽  
María R. Herrera-Rivera ◽  
Hugo Rojas-Chávez ◽  
Heriberto Cruz-Martínez ◽  
Dora I. Medina
Keyword(s):  
Carbon Monoxide ◽  
High Performance ◽  
Gas Sensing ◽  
Experimental Studies ◽  
Electrical Performance ◽  
Long Term Stability ◽  
Sensing Applications ◽  
Recent Advances ◽  
Sensitivity And Selectivity ◽  
Doped Zno

Monitoring and detecting carbon monoxide (CO) are critical because this gas is toxic and harmful to the ecosystem. In this respect, designing high-performance gas sensors for CO detection is necessary. Zinc oxide-based materials are promising for use as CO sensors, owing to their good sensing response, electrical performance, cost-effectiveness, long-term stability, low power consumption, ease of manufacturing, chemical stability, and non-toxicity. Nevertheless, further progress in gas sensing requires improving the selectivity and sensitivity, and lowering the operating temperature. Recently, different strategies have been implemented to improve the sensitivity and selectivity of ZnO to CO, highlighting the doping of ZnO. Many studies concluded that doped ZnO demonstrates better sensing properties than those of undoped ZnO in detecting CO. Therefore, in this review, we analyze and discuss, in detail, the recent advances in doped ZnO for CO sensing applications. First, experimental studies on ZnO doped with transition metals, boron group elements, and alkaline earth metals as CO sensors are comprehensively reviewed. We then focused on analyzing theoretical and combined experimental–theoretical studies. Finally, we present the conclusions and some perspectives for future investigations in the context of advancements in CO sensing using doped ZnO, which include room-temperature gas sensing.

scholarly journals Study of silicon nitride O-ring resonator for gas-sensing applications

2020 ◽  
Vol 1695 ◽  
pp. 012124
Author(s):  
A Elmanova ◽  
P An ◽  
V Kovalyuk ◽  
A Golikov ◽  
I Elmanov ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Ring Resonator ◽  
Gas Sensing ◽  
Sensing Applications
Sign in / Sign up

Export Citation Format

Share Document