scholarly journals Effects of Surfactants on the Performance ofCeO2Humidity Sensor

2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
Chunjie Wang ◽  
Aihua Zhang ◽  
Hamid Reza Karimi
Keyword(s):  
Recovery Time ◽  
Cetyltrimethylammonium Bromide ◽  
Humidity Sensor ◽  
X Ray Diffraction ◽  
Humidity Sensors ◽  
X Ray ◽  
Transmission Electron ◽  
Three Samples ◽  
Different Types ◽  
Response And Recovery

NanosizedCeO2powders were synthesized via hydrothermal method with different types of surfactants (polyethylene glycol (PEG), cetyltrimethylammonium bromide (CTAB), and sodium dodecylbenzenesulfonate (SDBS)). X-ray diffraction, Raman spectroscopy, and transmission electron microscopy were utilized to characterize the phase structures and morphologies of the products. The sample with CTAB as surfactant (CeO2-C) has the largest specific surface area and the smallest particle size among these three samples. The humidity sensor fabricated byCeO2-C shows higher performance than those usedCeO2-P andCeO2-S. The impedance of theCeO2-C sensor decreases by about five orders of magnitude with relative humidity (RH) changing from 15.7 to 95%. The response and recovery time are 7 and 7 s, respectively. These results indicate that the performance ofCeO2humidity sensors can be improved effectively by the addition of cationic surfactant.

Cetyltrimethylammonium bromide- and ethylene glycol-assisted preparation of mono-dispersed indium oxide nanoparticles using hydrothermal method

2014 ◽  
Vol 68 (8) ◽  
Author(s):  
Selvakumar Dhanasingh ◽  
Dharmaraj Nallasamy ◽  
Saravanan Padmanapan ◽  
Vinod Padaki
Keyword(s):  
Ethylene Glycol ◽  
Hydrothermal Method ◽  
Indium Oxide ◽  
Cetyltrimethylammonium Bromide ◽  
Oxide Nanoparticles ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
Transmission Electron ◽  
Diffraction Patterns

AbstractThe influence of cetyltrimethylammonium bromide and ethylene glycol on the size and dispersion of indium oxide nanoparticles prepared under hydrothermal conditions was investigated. The precursor compound, indium hydroxide, obtained by the hydrothermal method in the absence as well as the presence of cetyltrimethylammonium bromide, was converted to indium oxide by sintering at 400°C. The formation of nanoscale indium oxide upon sintering was ascertained by the characteristic infrared adsorption bands and X-ray diffraction patterns of indium oxide. Transmission electron microscopy and band gap values confirmed that the cetyltrimethylammonium bromide facilitated the formation of indium oxide nanoparticles smaller in size and narrower in distribution than those prepared without the assistance of cetyltrimethylammonium bromide.

Detection of accumulated continuously ethanol concentration by ZnO–SnO2 composite nanorods sensor

2021 ◽  
pp. 2150395
Author(s):  
Xiang-Bing Li ◽  
Da-Qian Mo ◽  
Xiao-Yan Niu ◽  
Qian-Qian Zhang ◽  
Shu-Yi Ma ◽  
...  
Keyword(s):  
Recovery Time ◽  
Ethanol Concentration ◽  
Physical Adsorption ◽  
X Ray Diffraction ◽  
Gas Sensitivity ◽  
X Ray ◽  
Atomic Force ◽  
Electrospinning Method ◽  
Response And Recovery ◽  
Composite Nanorods

ZnO–SnO2 composite nanorods with rough surfaces were synthesized via a coaxially nested needle electrospinning method. The morphology and nanostructure were characterized by scanning electron microscopy, atomic force microscope, EDS mapping, nitrogen physical adsorption, and X-ray diffraction. The synthesis mechanisms of ZnO–SnO2 nanorods were discussed, which combined the gas sensitivity advantages of different materials. ZnO–SnO2 nanorods sensor with good ethanol gas sensitivity achieved accurate measurement of continuous ethanol concentration. The sensor exhibited good selectivity to ethanol in the presence of formaldehyde, methanol, acetone, acetic acid, benzene, and xylene at 290[Formula: see text]C. The response and recovery time to 100 ppm ethanol were about 13 and 35 s, respectively. The energy band, barrier, charge transfer of ZnO–SnO2 composite material was discussed, and its optimization of gas sensitivity was analyzed in detail.

Ultrafast Response Humidity Sensor Based on Electrospun Porous BaTiO3 Nanofibers

2013 ◽  
Vol 319 ◽  
pp. 43-48 ◽  
Author(s):  
Hong Di Zhang ◽  
Chen Hao Sheng ◽  
Bin Sun ◽  
Yun Ze Long
Keyword(s):  
Electron Microscope ◽  
Recovery Time ◽  
Room Temperature ◽  
Humidity Sensor ◽  
Humidity Sensing ◽  
X Ray ◽  
Transmission Electron ◽  
Porous Microstructure ◽  
Humidity Sensing Properties ◽  
Scanning Electron

Nanocrystalline and porous barium titanate (BaTiO3) nanofibers with diameter 200-400 nm were synthesized via electrospinning and followed calcinations. The morphology and microstructure of the nanofibers were characterized using field emission scanning electron microscope, X-ray diffractometer and transmission electron microscope, respectively. And the electrical and humidity sensing properties of the nanofibers were also measured. The results reveal that the BaTiO3 nanofibers have a conductivity of about 0.3 S/cm, and show an ultrafast response time (~0.7 s) and a recovery time (~0.4 s) to humidity at room temperature. In addition, the sensing mechanism was also discussed briefly based on its nanocrystalline and porous microstructure of the electrospun material.

scholarly journals Insights into the multistep transformation of titanate nanotubes into nanowires and nanoribbons

2016 ◽  
Vol 34 (4) ◽  
pp. 691-702 ◽  
Author(s):  
Agnieszka Baszczuk ◽  
Marek Jasiorski ◽  
Beata Borak ◽  
Jerzy Wódka
Keyword(s):  
Treatment Duration ◽  
Hydrothermal Reaction ◽  
X Ray Diffraction ◽  
One Dimensional ◽  
X Ray ◽  
Transmission Electron ◽  
Morphology And Structure ◽  
Different Types ◽  
Increasing Temperature

AbstractDifferent types of titanate one-dimensional nanostructured materials were synthesized and characterized using scanning and transmission electron microscopy, X-ray diffraction and Raman spectroscopy. The results presented in this work unquestionably showed dependence of morphology and structure of the titanate nanopowders on parameters of hydrothermal synthesis. It was found that nanotubes, nanowires and nanoribbons are three unavoidable kinetic products of hydrothermal reaction. Moreover, increasing temperature of reaction or hydrothermal treatment duration results in acceleration of nanotube-nanowire-nanoribbon transformation. However, the sequence of titanate morphology transformation is invariable. The detailed studies further revealed that the crystal structure of hydrothermally prepared nanotubes and nanowires are indistinguishable but the determination of the exact structure is practically impossible. Because of higher crystallinity, the structure of nanoribbons can be established. It was shown that it corresponds to the monoclinic layered trititanic acid H2Ti3O7 and is isostructural with sodium derivatives Na2_xHxTi3O7.nH20 (with x near 2).

scholarly journals Adsorption characteristics of 2,4-dichorophenoxy acetic acid onto surfactant modified titania nanoparticles

2021 ◽  
Vol 10 (4) ◽  
pp. xx-xx
Author(s):  
Dung Le Thi ◽  
Loan Nguyen Quynh ◽  
Thang Nguyen Duc ◽  
Son Le Thanh ◽  
Duc Pham Tien
Keyword(s):  
Acetic Acid ◽  
Surface Modification ◽  
Cetyltrimethylammonium Bromide ◽  
Sol Gel ◽  
Titania Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Adsorption Mechanisms ◽  
Transmission Electron ◽  
Effective Conditions

The present study investigated adsorption of 2,4-dichorophenoxy acetic acid(2,4-D) on titania (TiO2) nanoparticles with surface modification by cationic surfactant, cetyltrimethylammonium bromide (CTAB). Titania nanoparticles which were successfully synthesized by sol-gel method, were characterized by X-ray diffraction (XRD) and Transmission electron microscopy (TEM). Surface modification of TiO2 with CTAB enhanced the removal of 2,4-D significantly. Some effective conditions affect to the removal of 2,4-D using CTAB modified TiO2 such as pH and adsorbent dosage were systematically studied and found to be 5 and 10 mg/mL, respectively. Adsorption mechanisms of 2,4-D onto CTAB modified TiO2 was suggested based on the change in surface charge after adsorption. 

scholarly journals Humidity Sensing and Photodetection Based on Tin Disulfide Nanosheets

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1028
Author(s):  
Der-Yuh Lin ◽  
Hung-Pin Hsu ◽  
Han-Sheng Hu ◽  
Yu-Cheng Yang ◽  
Chia-Feng Lin ◽  
...  
Keyword(s):  
Humidity Sensor ◽  
Electrode Spacing ◽  
X Ray Diffraction ◽  
Humidity Sensing ◽  
X Ray ◽  
Tin Disulfide ◽  
Human Respiration ◽  
Response And Recovery ◽  
H2o2 Oxidation ◽  
Measured Response

Tin disulfide has substantial importance for two-dimensional material-based optoelectronics and sensors due to its unique optoelectrical properties. In this report, we fabricate SnS2 nanosheets using the low-pressure thermal sulfurization process, whose crystal structure and surface morphology are confirmed by X-ray diffraction (XRD) and scanning electron microscope (SEM) measurements. From photoconductivity measurement and photocurrent mapping, we observe smaller electrode spacing of SnS2 thin films can enhance photodetection. Then, by the H2O2 oxidation processing, we transform SnS2 to SnO2 to detect humidity. The measured response and recovery time can be optimized to 5.6 and 1.0 s, respectively, shorter than those of commercial DHT11 humidity sensor of 32 and 34 s. At suitable bias, humidity sensor can detect human respiration properly at room temperature. Our results show that SnS2 nanosheets exhibit reasonable performance for emergent photodetector applications and humidity sensing.

Synthesis and Characterization of Tin Oxide Nanoparticle for Humidity Sensor Applications

2009 ◽  
Vol 4 ◽  
pp. 91-101 ◽  
Author(s):  
T. Krishnakumar ◽  
R. Jayaprakash ◽  
V.N. Singh ◽  
B.R. Mehta ◽  
A.R. Phani
Keyword(s):  
Tin Oxide ◽  
Humidity Sensor ◽  
X Ray Diffraction ◽  
Sensor Applications ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Response And Recovery ◽  
Ft Ir ◽  
Oxide Nanoparticle

Tin oxide nanoparticle was successfully prepared by the chemical digestion method from the starting material as SnCl2. The SnO2 material was characterized by X-Ray Diffraction (XRD), Transmission Electron Microscope (TEM) and Selected Area Electron Diffraction (SAED). The SnO2 was an n-type material preferred to humidity sensing property towards the moisture. The response and recovery time of sensor was calculated as 129sec and 206sec respectively. It has exhibited better efficiency compared with the bulk SnO2 material. Additional Weight loss, EDS, FT-IR and resistivity measurements were also presented.

Structure of UMoO5 studied by single-crystal X-ray diffraction and high-resolution transmission electron microscopy

1996 ◽  
Vol 52 (6) ◽  
pp. 961-965 ◽  
Author(s):  
O. G. D'yachenko ◽  
V. V. Tabachenko ◽  
R. Tali ◽  
L. M. Kovba ◽  
B.-O. Marinder ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Slight Excess ◽  
Transmission Electron ◽  
Different Types

A combination of X-ray diffraction and high-resolution transmission electron microscopy (HRTEM) has been used to study the crystal structure of molybdenum uranium pentoxide, UMoO5, obtained by hydrothermal and ceramic methods. Crystal data: Mr = 414.0, orthorhombic, Pbaa (number 54), a = 12.746 (1), b = 7.3494 (7), c = 4.1252 (2) Å, V = 386.4 (1) Å3, Z = 4, Dx = 7.116 Mg m−3, R = 0.037 for 723 reflections. The structure of UMoO5 is related to that of UVO5. Both are built up by slabs of pentagonal UO7 bipyramids with slabs of MO6 octahedra in-between. They differ in symmetry due to different types of displacement of the M atoms from the ab plane. The HRTEM study revealed a few defect regions in the UMoO5 crystals prepared by ceramic methods. Energy-dispersive spectroscopy (EDS) analyses indicate a slight excess of uranium in such crystals. Hypothetical models of defect regions are given.

Encapsulation of anion-cation organo-montmorillonite in terpolymer microsphere: structure, morphology, and properties

2020 ◽  
Vol 40 (4) ◽  
pp. 321-332
Author(s):  
Yuan Lin ◽  
Yangchuan Ke ◽  
Chengcheng Yu ◽  
Xu Hu ◽  
Shichao Lu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cetyltrimethylammonium Bromide ◽  
Suspension Polymerization ◽  
X Ray Diffraction ◽  
High Permeability ◽  
X Ray ◽  
Inverse Suspension Polymerization ◽  
Transmission Electron ◽  
Structure Morphology

AbstractExfoliated organo-montmorillonite (O-Mt) layers were successfully encapsulated in a terpolymer microsphere (PAAA) of acrylamide (AM)/acrylic acid (AA)/2-acrylamido-2-methylpropanesulfonic acid (AMPS) via in situ inverse suspension polymerization, with the aid of the organic modification by cetyltrimethylammonium bromide (CTAB) and sodium lauryl sulfonate (SLS). The chemical structure and properties of the Mt were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA), which showed that SLS molecules successfully intercalated Mt interlayers and enhanced the thermostability of Mt. The microsphere morphologies of the polymer and its nanocomposites were detected by scanning electron microscopy (SEM). The results of X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed that the exfoliated O-Mt dispersed in the polymer matrix. The introduction of well-dispersed O-Mt layers significantly enhanced the comprehensive performance of these microspheres, including thermostability and plugging properties. The Tmax of PAAA/1.5 wt.% O-Mt nanocomposite is increased by 46°C compared to the pure terpolymer. The plugging rate of PAAA/2.0 wt.% O-Mt reached up to 85.8%. Therefore, these selected nanocomposite microspheres can provide an effective plugging in the high-permeability layers.

Nature of interstratified kaolin-smectites in some Australian soils

Soil Research ◽  
1994 ◽  
Vol 32 (4) ◽  
pp. 805 ◽  
Author(s):  
GJ Churchman ◽  
PG Slade ◽  
PG Self ◽  
LJ Janik
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Infrared Spectroscopy ◽  
Clay Minerals ◽  
X Ray Diffraction ◽  
Size Fractions ◽  
X Ray ◽  
Transmission Electron ◽  
Different Types ◽  
Interstratified Phase

The clay minerals in the < 2 �m, and finer, size fractions of several horizons from each of five Australian soils of different types and from different locations have been analysed by X-ray diffraction, infrared spectroscopy, transmission electron microscopy and X-ray fluorescence. Samples from each profile contained a phase in which layers of smectite and of kaolin (positively identified as kaolinite) were randomly interstratified with each other. The relative proportions of the two types of layers varied widely. One interstratified phase contained 70% smectite. This value for smectite content of kaolin-smectites is as high as any reported in the literature. The charges associated with the interstratified smectite layers also differed substantially. Discrete kaolinite commonly occurred along with interstratified kaolinite-smectite, Towards the surfaces of the soils, the proportions of kaolinite in the interstratified phases increased at the expense of smectite.

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