scholarly journals SYNTHESIS AND CHARACTERIZATION OF Co3O4 POWDERS FOR HUMIDITY SENSING

2012 ◽  
Vol 06 ◽  
pp. 197-202 ◽  
Author(s):  
P. N. SHELKE ◽  
Y. B. KHOLLAM ◽  
P. N. PABREKAR ◽  
P. S. MORE ◽  
A. M. DATIR ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Wide Spectrum ◽  
Pollution Monitoring ◽  
Gas Detection ◽  
X Ray Diffraction ◽  
Gaseous Species ◽  
Humidity Sensing ◽  
Prepared Powder ◽  
Naoh Solution

In last few decades, great deal of research efforts were directed towards the development of miniaturized gas-sensing devices, particularly for toxic gas detection and for pollution monitoring. Though various techniques are available for gas detection, solid state metal oxides offer wide spectrum of materials with their high sensitivities for the detection of different gaseous species. In this paper, we report the humidity sensing behavior of cobalt oxide ( Co 3 O 4) pellets. The Co 3 O 4 powder was prepared from the precipitation of CoSO 4 using NaOH solution. This as-prepared powder was heated at 600 °C for 2hr. The as-prepared powder was characterized by using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The humidity sensing behavior of Co 3 O 4 pellets (wt. ~ 0.5 gm, diameter ~ 10 mm) was noted by using home-built static gas sensing system. The characterization studies showed the high material purity and single phase Co 3 O 4 with cubic spinel symmetry in the as-prepared particles of resultant powders. The humidity sensing characteristics of Co 3 O 4 pellets were found to be good. The recovery time (~ 20 sec) was found to be small as compared to its response time (~ 60 sec).

scholarly journals Characterization of CuO thin films for gas sensing applications

2019 ◽  
Vol 14 (31) ◽  
pp. 1-12
Author(s):  
Jamal M. Rzaij
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Cupric Oxide ◽  
Laser Pulses ◽  
X Ray Diffraction ◽  
Energy Increase ◽  
Nano Structure ◽  
X Ray ◽  
Sensing Applications

Nanostructural cupric oxide (CuO) films were prepared on Si and glass substrate by pulsed laser deposition technique (PLD) using laser Nd:YAG, using different laser pulses energies from 200 to 600 mJ. The X-ray diffraction pattern (XRD) of the films showed a polycrystalline structure with a monoclinic symmetry and preferred orientation toward (111) plane with nano structure. The crystallite size was increasing with increasing of laser pulse energy. Optical properties was characterized by using UV–vis spectrometer in the wave lengthrange (200-1100) nm at room temperature. The results showed that the transmission spectrum decreases with the laser pulses energy increase. Sensitivity of NO2 gas at different operating temperatures, (50°C, 100°C, 150°C and 200°C) was calculated.

scholarly journals Synthesis and Characterization of Single-Crystalline SnO2Nanowires

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Dezhou Wei ◽  
Yanbai Shen ◽  
Mingyang Li ◽  
Wengang Liu ◽  
Shuling Gao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Gas Sensing ◽  
Operating Temperature ◽  
Ambient Pressure ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Peak Sensitivity ◽  
The Fourier Transform

Tin oxide (SnO2) nanowires were synthesized on oxidized silicon substrates by thermal evaporation of tin grains at 900°C in Ar flow at ambient pressure. Structural characterization using X-ray diffraction and transmission electron microscopy shows that SnO2nanowires have a single crystal tetragonal structure. Scanning electron microscopy observation demonstrates that SnO2nanowires are 30–200 nm in diameter and several tens of micrometers in length. The surface vibration mode resulting from the nanosize effect at 565.1 cm−1was found from the Fourier transform infrared spectrum. The formation of SnO2nanowires follows a vapour-solid (VS) growth mechanism. The gas sensing measurements indicate that SnO2nanowire gas sensor obtains peak sensitivity at a low operating temperature of 150°C and shows reversible response to H2gas (100–1000 ppm) at an operating temperature of RT-300°C.

scholarly journals Growth and Characterization of Ni Nano-Micro Structures in the Presence of Ethylenediamine

Crystals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 397 ◽  
Author(s):  
Lingxiao Chen ◽  
Hang Liu ◽  
Linghao Liu ◽  
Yifan Zheng ◽  
Haodong Tang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Alkaline Conditions ◽  
Naoh Solution ◽  
Micro Structures ◽  
Scanning Electron

Ni nano-micro structures have been synthesized via a solution reduction route in the presence of ethylenediamine (EDA) under strong alkaline conditions. The phase composition, morphology, and microstructure of the resulting products are investigated by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The presence of EDA plays an important role in the formation of Ni nano-micro structures, and microflowers or microspheres assembled from nanosized horns can be produced by changing the amount of EDA. The size of Ni nano-micro structures is dependent on the NaOH concentration, and long chains assembled from Ni nano-micro structured microspheres can be obtained by reducing the amount of NaOH solution used. The role of both EDA and NaOH in the reduction of Ni (II) to Ni, as well as in the growth of Ni nano-micro structures, has been discussed, and a possible formation mechanism of these Ni nano-micro structures has been proposed based on the experimental results.

Characterization of Difference Size of IDE Pattern for Formaldehyde Detection Sensor

2015 ◽  
Vol 754-755 ◽  
pp. 917-922 ◽  
Author(s):  
M. Zaki ◽  
Uda Hashim ◽  
Mohd Khairuddin Md Arshad ◽  
M.F.M. Fathil ◽  
A.H. Azman ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Low Cost ◽  
Electrical Characterization ◽  
Gas Detection ◽  
Si Substrate ◽  
Hard Mask ◽  
Large Size ◽  
Mask Design ◽  
The Ideal

This paper studies the effect of different gap sizes of IDE pattern on the surface morphology and electrical properties for the formaldehyde detection sensor. Two types of IDE chrome mask are designed to determine the ideal IDE pattern for formaldehyde gas detection by using conventional lithography. In the first method, IDE is transferred onto SiO2layer. In order to ensure that the perfect pattern with minimum defect structure is obtained, the process parameters should be optimized and controlled. In the second method, the aluminium is deposited directly on SiO2/Si substrate by using IDE hard mask design plate. The fabricated IDE pattern is further validated through morphological and electrical characterization. The average gap size of IDE sensor is approximately 100 μm and 400 μm for IDE chrome and IDE hard mask respectively. The latter method is preferable since for formaldehyde gas sensing large size is needed and moreover the process is simple and requires low cost. Characterization of difference IDE pattern is demonstrated by various measurements.

Use of Fly Ash and Cu-Slag from Mexico to Make Alkali Cements and Hybrid Cements

2016 ◽  
Vol 1813 ◽  
Author(s):  
M. Rendón Belmonte ◽  
A. Palomo Sánchez ◽  
A. Fernández Jiménez ◽  
A. Torres Acosta ◽  
M. Martínez Madrid ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Fly Ash ◽  
Chemical Characterization ◽  
Copper Slag ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
X Ray ◽  
Naoh Solution ◽  
Scanning Electron

ABSTRACTThis paper focus on evaluating the ability to use Mexican fly ash (FA) and copper slag (CS) to produce alkali cements (0% OPC) or hybrid cements (20% OPC + 80% fly ash). The alkali activators used were two: 8 M NaOH solution for alkali cements and NaCl with sodium silicate for hybrid cement (HYC). Results of mechanical testing and characterization of the reaction products formed after 2 and 28 days are presented and discussed. Mechanical strength in some cases exceeded 20 MPa, at 2 days curing. The chemical characterization techniques used were X-Ray Diffraction (XRD) and scanning electron microscopy (SEM).

Detailed Characterization of Surface Ln-Doped Anatase TiO2 Nanoparticles by Hydrothermal Treatment for Photocatalysis and Gas Sensing Applications

2015 ◽  
Vol 1806 ◽  
pp. 25-30
Author(s):  
Rezwanur Rahman ◽  
Sean T. Anderson ◽  
Sonal Dey ◽  
Robert A. Mayanovic
Keyword(s):  
Hydrothermal Treatment ◽  
Gas Sensing ◽  
Ambient Air ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Heterogeneous Distribution ◽  
Sensing Applications ◽  
Hole Defects ◽  
Made In

ABSTRACTNanostructured anatase TiO2 is a promising material for gas sensing and photocatalysis. In order to modify its catalytic properties, the lanthanide (Ln) ions Eu3+, Gd3+, Nd3+ and Yb3+ were precipitated on the surface of TiO2 nanoparticles (NPs) by hydrothermal treatment. Results from Raman spectroscopy and X-ray diffraction (XRD) measurements show that the anatase structure of the TiO2 nanoparticles was preserved after hydrothermal treatment. SEM and TEM show a heterogeneous distribution in size and a nanocrystallite morphology of the TiO2 NPs (∼ 14 nm in size) and EDX confirmed the presence of the Ln-ion surface doping after hydrothermal treatment. An increase in photoluminescence (PL) was observed for the Ln-surface-doped TiO2 NPs when measurements were made in forming gas (5% H2 + 95% Ar) at 520 °C. In contrast, the PL measurements made at room temperature did not show any noticeable difference in forming gas or in ambient air. Our temperature-dependent PL results obtained in different gas environments are consistent with modification of oxygen-vacancies and hole-defects due to a combination of hydrothermal treatment and surface Ln-doping.

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%

SYNTHESIS AND CHARACTERIZATION OF PURE AND Zn-DOPED SnO2 NANOPOWDERS

2013 ◽  
Vol 22 ◽  
pp. 452-457 ◽  
Author(s):  
PARUL GUPTA ◽  
RISHI VYAS ◽  
B. L. CHOUDHARY ◽  
K. SACHDEV ◽  
D. S. PATIL ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Sol Gel ◽  
Average Crystallite Size ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Sensing Applications ◽  
Zn Addition ◽  
Vis Spectroscopy ◽  
Electrical Characterizations

Pure and 4.5 wt% Zn- doped SnO2 nanopowders were synthesized by sol-gel method. These nanopowders were characterized by X- ray diffraction, Scanning electron microscopy, UV-Vis spectroscopy, I-V measurements and R-T measurements. XRD results confirmed the formation of tetragonal rutile type SnO2 with the average crystallite size of 14 ± 1 nm which decreased to 9 ± 1 nm with 4.5 wt% Zn addition. Increase in band gap is observed from UV-Vis spectroscopy. Electrical characterizations revealed increase in resistivity with Zn addition. Temperature dependent resistance measurement showed that both the pure and the Zn- doped samples are suitable for gas sensing applications. A detailed study of these synthesized nanostructured samples is presented and discussed in the paper.

scholarly journals Comparison of Gas Sensing Properties of Reduced Graphene Oxide Obtained by Two Different Methods

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3175
Author(s):  
Sabina Drewniak ◽  
Marcin Procek ◽  
Roksana Muzyka ◽  
Tadeusz Pustelny
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Gas Sensing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sorption Method ◽  
Reduced Graphene ◽  
Gaseous Atmospheres

In this study, the sensitivity of reduced graphene oxide structures (rGO) to the action of selected gases (especially hydrogen, but also nitrogen dioxide and ammonia) was examined. Two sensing structures, based on rGO structures, obtained by different methods of oxidation (the modified Hummers, and the modified Tour’s method respectively), were investigated. We show here that the method used for the oxidation of rGO influences the sensitivity of the sensing structure during contact with various gaseous atmospheres. We performed our experiments in the atmosphere, containing hydrogen in a concentration range from 0 to 4% in nitrogen or synthetic air, both in dry and wet conditions. The temperature range was from 50 °C to 190 °C. Finally, we checked how the resistance of the samples changes when the other gases (NO2, NH3) appear in tested gas mixtures. The gas investigations were supplemented by the characterization of rGOs materials using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and N2 sorption method.

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