scholarly journals Synthesis and Characterization ofLiNiO2Nanopowder with Various Chelating Agents

2010 ◽  
Vol 2010 ◽  
pp. 1-6 ◽  
Author(s):  
Mehrdad Balandeh ◽  
Sirous Asgari
Keyword(s):  
Particle Size ◽  
Intensity Ratio ◽  
Metal Ion ◽  
Chelating Agents ◽  
Average Particle Size ◽  
Chelating Agent ◽  
Molar Ratio ◽  
Average Particle ◽  
Tem Analysis ◽  
Transmission Electron

LiNiO2powders were synthesized with acrylic acid, citric acid, oxalic acid, and triethanolamine (TEA) as a chelating agent. CrystallizedLiNiO2was synthesized in air at a calcinations temperature of 500∘Cfor 12 hours, when the molar ratio of chelating agents to total metal ion (RPM) was 1.0. The TEA-assisted method had the highest intensity ratio of (003)/(104) peaks of X-ray diffraction (XRD) spectrum. The transmission electron microscopy (TEM) analysis indicates that the sample prepared with triethanolamine obtained the smallest particle size with average particle size of only 12 nm. The results indicate that chelating agents have an important role in the intensity ratio of (003)/(104) peaks of XRD spectrum, size and shape of powders.

Particle Size Control, Structure and Magnetic Characterization of Cobalt Nanoparticles

2007 ◽  
Vol 998 ◽  
Author(s):  
Abhishek Singh ◽  
Nirav Parekh ◽  
Gregory Young ◽  
Kiumars Parvin ◽  
Maninder Kaur ◽  
...  
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Size Control ◽  
Reduction Reaction ◽  
Cobalt Nanoparticles ◽  
Molar Ratio ◽  
Ferromagnetic Behavior ◽  
Average Particle ◽  
Transmission Electron ◽  
Precursor Material

ABSTRACTCobalt nanoparticles were synthesized by means of a hot metal reduction reaction with cobalt chloride as precursor material. The size of cobalt nanoparticles was controlled by the choice of surfactant and the molar ratio of surfactant-to-reagent. Surfactants with larger alkane side chains yielded a smaller average nanoparticle size (diameter) and tighter size distribution, as these chains provided steric hindrance to the growth of the nanoparticles after initial nucleation. For each alkane side chain, a high molar ratio of surfactant-to-reagent (HSR) rendered nanoparticles with smaller particle size, while a low molar ratio of surfactant-to-reagent (LSR) produced larger nanoparticles. Measurements on transmission electron microscope images of cobalt particles synthesized with tri-octylphosphine revealed an average particle size of 6.9 nm (HSR) and 9.1 nm (LSR), while particles synthesized with tri-butylphosphine had a mean diameter of 12.5 nm (HSR) and 14.9 nm (LSR). X-ray diffraction profiles indicated that particles had metastable ε-cobalt structure. Room temperature magnetization measurements showed ferromagnetic behavior with highly square M-H loops indicative of single domain particles with coercive fields in the range of 400–500 Oe.

Size Tunablity of CdTe Crystallites in Dendrimer Nanocomposites and Temperature Dependent Focusing of Size Distribution

2008 ◽  
Vol 8 (11) ◽  
pp. 5952-5957
Author(s):  
Srabanti Ghosh ◽  
Amiya Priyam ◽  
Anindita Chatterjee ◽  
Abhijit Saha
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Average Particle Size ◽  
Tight Binding ◽  
Molar Ratio ◽  
Average Particle ◽  
Electron Microscopic ◽  
Tight Binding Approximation ◽  
Transmission Electron ◽  
Transmission Electron Microscopic

CdTe/Dendrimer nanocomposites have been synthesized for the first time in aqueous and non-aqueous media using PAMAM dendrimer (Generation 5.0). The average size of the as-prepared nanocomposites, as determined from dynamic light scattering (DLS) measurements, was found to be typically 182 nm and 23 nm in water and methanol, respectively under identical conditions of temperature (5 °C) and reagent ratio (Cd2+:Te2−, 1:0.5). The size of CdTe NPs within the nanocomposites, was found to be 3.1 and 2.8 nm for the aforementioned samples determined from optical absorption spectra using tight binding approximation. The NPs possess good degree of cystallinity as discernible from the lattice fringes in high-resolution transmission electron microscopic (HRTEM). Transmission electron microscopic (TEM) image and the cubic crystal phase was ascertained from the small area electron diffraction (SAED) pattern. Analysis of FTIR data suggests that CdTe NPs are bound to the surface amine groups as well as –NHCO– moieties lying in the interior of dendrimer structure. The present work demonstrates how the quality of the CdTe NPs formed within the dendrimer matrix can be nicely tuned by varying the parameters, namely, temperature, molar ratio of Cd2+:Te2− and pH. Changing of Cd2+:Te2− ratio of 1:1 to 1:0.5, decreased the average particle size from 5.0 nm to 3.4 nm with concomitant narrowing of size distribution by ∼35% at 10 °C. On lowering down the synthesis temperature (25 °C→5 °C), the average particle size remained unaffected while the size distribution became sharply focused. However, the extent of focusing was found to be more in methanol (40%) than that in water (30%).

scholarly journals Behavior of Particle Size Distributions, Means and BET Values in Ideal and Non-Ideal Morphology Systems in a TEM

2004 ◽  
Vol 12 (1) ◽  
pp. 30-33
Author(s):  
Paul Beauregard
Keyword(s):  
Particle Size ◽  
Surface Area ◽  
Average Particle Size ◽  
Atomic Layer ◽  
Average Particle ◽  
Tem Analysis ◽  
Transmission Electron ◽  
New Instrument ◽  
The Cost

Historically, one of the first jobs performed by the new instrument called a “transmission electron microscope” (TEM) was the determination of particle size and distribution. Particle size is still important in controlling the properties of sub-micron and nanoparticle products. The width and average particle size can determine the light scattering properties of a pigment like TiO2, for example. The cost of installing a TEM facility and TEM sample preparation issues makes TEM analysis expensive and labor intensive. So decades ago, nitrogen BET (Brunauer, Emmett, and Teller) surface area determinations were used on sub-micron powders and pigments to minimize these costs. The BET measurement of the exposed external surface area of a material is made by detecting and measuring the amount of nitrogen given off after absorption, assuming one atomic layer of nitrogen is adsorbed.

scholarly journals Synthesis and Characterization of CuIn1−xGaxSe2 Semiconductor Nanocrystals

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 2066
Author(s):  
Yu-Tai Shih ◽  
Yu-Ching Tsai ◽  
Der-Yu Lin
Keyword(s):  
Particle Size ◽  
Semiconductor Nanocrystals ◽  
Average Particle Size ◽  
Band Gap Energy ◽  
Chalcopyrite Structure ◽  
Synthesis And Characterization ◽  
Average Particle ◽  
Tem Analysis ◽  
Transmission Electron

In this paper, the synthesis and characterization of CuIn1−xGaxSe2 (0 ≤ x ≤ 1) nanocrystals are reported with the influences of x value on the structural, morphological, and optical properties of the nanocrystals. The X-ray diffraction (XRD) results showed that the nanocrystals were of chalcopyrite structure with particle size in the range of 11.5–17.4 nm. Their lattice constants decreased with increasing Ga content. Thus, the x value of the CuIn1−xGaxSe2 nanocrystals was estimated by Vegard’s law. Transmission electron microscopy (TEM) analysis revealed that the average particle size of the nanocrystals agreed with the results of XRD. Well-defined lattice fringes were shown in the TEM images. An analysis of the absorption spectra indicated that the band gap energy of these CuIn1−xGaxSe2 nanocrystals was tuned from 1.11 to 1.72 eV by varying the x value from 0 to 1. The Raman spectra indicated that the A1 optical vibrational mode of the nanocrystals gradually shifted to higher wavenumber with increasing x value. A simple theoretical equation for the A1 mode frequency was proposed. The plot of this equation showed the same trend as the experimental data.

Microstructure Characterization of Ag Nanoparticles Prepared by Hydrothermal Method

2012 ◽  
Vol 476-478 ◽  
pp. 1138-1141
Author(s):  
Zhi Qiang Wei ◽  
Qiang Wei ◽  
Li Gang Liu ◽  
Hua Yang ◽  
Xiao Juan Wu
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Hydrothermal Method ◽  
Ag Nanoparticles ◽  
Average Particle Size ◽  
Average Particle ◽  
Face Centered Cubic ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Face Centered

Ag nanoparticles were successfully synthesized by hydrothermal method under the polyol system combined with traces of sodium chloride, Silver nitrate(AgNO3) and polyvinylpyrrolidone (PVP) acted as the silver source and dispersant respectively. The samples by this process were characterized via X-ray powder diffraction (XRD), Brunauer–Emmett–Teller (BET) adsorption equation, transmission electron microscopy (TEM) and the corresponding selected area electron diffraction (SAED) to determine the chemical composition, particle size, crystal structure and morphology. The experiment results indicate that the crystal structure of the samples is face centered cubic (FCC) structure as same as the bulk materials, The specific surface area is 24 m2/g, the particle size distribution ranging from10 to 50 nm, with an average particle size about 26 nm obtained by TEM and confirmed by XRD and BET results.

Synthesis and Characterization of Water-Soluble Monolayer-Protected Gold Nanoparticles

2011 ◽  
Vol 415-417 ◽  
pp. 617-620 ◽  
Author(s):  
Yan Su ◽  
Ying Yun Lin ◽  
Yu Li Fu ◽  
Fan Qian ◽  
Xiu Pei Yang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Gold Nanoparticles ◽  
Average Particle Size ◽  
Water Soluble ◽  
Synthesis And Characterization ◽  
Average Particle ◽  
Transmission Electron

Water-soluble gold nanoparticles (AuNPs) were prepared using 2-mercapto-4-methyl-5- thiazoleacetic acid (MMTA) as a stabilizing agent and sodium borohydride (NaBH4) as a reducing agent. The AuNPs product was analyzed by transmission electron microscopy (TEM), UV-vis absorption spectroscopy and Fourier transform infrared spectroscopy (FTIR). The TEM image shows that the particles were well-dispersed and their average particle size is about 5 nm. The UV-vis absorption and FTIR spectra confirm that the MMTA-AuNPs was stabilized by the carboxylate ions present on the surface of the AuNPs.

Fe3O4 Magnetic Preparation by Bauxite Ore Washing Fine Mud

2014 ◽  
Vol 1010-1012 ◽  
pp. 961-965
Author(s):  
Jian Qiang Xiao ◽  
Guo Wei He ◽  
Yan Jin Hu
Keyword(s):  
Particle Size ◽  
Aging Time ◽  
Average Particle Size ◽  
Xrd Analysis ◽  
Test Methods ◽  
Raw Material ◽  
Molar Ratio ◽  
Average Particle ◽  
Experimental Conditions ◽  
Particle Size Analyzer

Bauxite waste sludge as a raw material, the use of reverse chemical coprecipitation synthesize Fe3O4. Researching temperature, precipitation concentration, aging time and Fe2+/Fe3+ molar ratio effect on the particle size, morphology. Optimal experimental conditions: temperature 70 °C, the precipitant NaOH mass ratio of 10%, aging time 3h, Fe2+/Fe3+ molar ratio of 2:3. Test methods using a laser particle size analyzer, XRD analysis of the products were characterized, the product is Fe3O4, the average particle size of 0.11mm.

Low Temperature Hydrothermal Synthesis of Nanophase BaTiO3 and BaFe12O19 Powders

1996 ◽  
Vol 457 ◽  
Author(s):  
Fatih Dogan ◽  
Shawn O'rourke ◽  
Mao-Xu Qian ◽  
Mehmet Sarikaya
Keyword(s):  
Particle Size ◽  
Hydrothermal Reaction ◽  
Average Particle Size ◽  
Reaction Times ◽  
Nanocrystalline Powders ◽  
Molar Ratio ◽  
Average Particle ◽  
Hydrothermal Conditions ◽  
Processing Variables ◽  
Xrd And Tem

ABSTRACTNanocrystalline powders with an average particle size of 50 nm has been synthesized in two materials systems under hydrothermal conditions below 100°C. Processing variables, such as temperature, concentration and molar ratio of reactants and reaction time were optimized to obtain particles of reduced size and stoichiometric compositions. Hydrothermal reaction takes place between Ba(OH)2 solution and titanium/iron precursors in sealed polyethylene bottles in the BaTiO3 and BaFe12O19 systems, respectively. While crystalline BaTiO3 forms relatively fast within a few hours, formation of fully crystalline and stoichiometric BaFei20i9 require considerably longer reaction times up to several weeks and strongly dependent on the Ba:Fe ratio of the precursors. The structural and compositional evaluation of the nanophase powders were studied by XRD and TEM techniques.

Facile Synthesis and Characterization of Fe-Co Nanoparticles Supported Silica Rice Husk

2016 ◽  
Vol 709 ◽  
pp. 66-69
Author(s):  
Jeyashelly Andas ◽  
Rahmah Atikah Rosdi ◽  
Nur Izzati Mohd Anuar
Keyword(s):  
Particle Size ◽  
Rice Husk ◽  
Sol Gel ◽  
Average Particle Size ◽  
Average Particle ◽  
Silica Source ◽  
Transmission Electron ◽  
Particle Size Analyzer ◽  
Bimetallic Materials ◽  
Co Nanoparticles

A series of Fe-Co nanoparticles were synthesized via sol-gel route at acidic, neutral and basic condition using rice husk as the silica source. The synthesized nanomaterials were designated as Fe-Co3, Fe-Co7 and Fe-Co9 and characterized by Fourier Transform Infrared (FTIR), Transmission Electron Microscope (TEM) and particle size analyzer. The great effect of pH was clearly evidenced from the shifting in the siloxane bond in the FTIR spectrum. TEM investigation confirmed the existence of discrete and almost sphere like nanoparticles. The particle size decreased with an increase in the pH, registering the smallest average particle size at pH 9. In brief, this study promises a fast, rapid and promising method for the conversion of silica rice husk into nanoscale bimetallic materials.

The Aggregation Study and Characterization of Silver Nanoparticles

2017 ◽  
Vol 263 ◽  
pp. 165-169
Author(s):  
Silvia Chowdhury ◽  
Faridah Yusof ◽  
Nadzril Sulaiman ◽  
Mohammad Omer Faruck
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Silver Nanoparticles ◽  
Absorption Spectrum ◽  
Average Particle Size ◽  
Average Particle ◽  
Transmission Electron ◽  
Vis Spectroscopy

In this article, we have studied the process of silver nanoparticles (AgNPs) aggregation and to stop aggregation 0.3% Polyvinylpyrrolidone (PVP) was used. Aggregation study carried out via UV-vis spectroscopy and it is reported that the absorption spectrum of spherical silver nanoparticles were found a maximum peak at 420 nm wavelength. Furthermore, Transmission Electron Microscopy (TEM) were used to characterized the size and shape of AgNPs, where the average particle size is around 10 to 25 nm in diameter and the AgNPs shape is spherical. Next, Dynamic Light Scattering (DLS) were used, owing to observed size distribution and self-correlation of AgNPs.

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