Preparation of Aerogel and Xerogel Nanocomposite Materials

1999 ◽  
Vol 581 ◽  
Author(s):  
M.F. Casula ◽  
A. Corrias ◽  
G. Paschina
Keyword(s):  
Iron Oxide ◽  
Nickel Oxide ◽  
Sol Gel ◽  
Morphological Characteristics ◽  
Oxide Nanoparticles ◽  
X Ray Diffraction ◽  
Nickel Oxide Nanoparticles ◽  
Silica Nanocomposites ◽  
Transmission Electron ◽  
Microscopy Techniques

ABSTRACTSol-gel method was used to prepare nickel oxide-silica and iron oxide-silica nanocomposites materials in form of aerogels and xerogels. The samples were characterized by thermal analysis, X-ray diffraction, N2 physisorption and transmission electron microscopy techniques. The variation of the supercritical solvent extraction conditions gives rise to differences in the morphological characteristics of the aerogels. These differences influence the size of the nickel oxide nanoparticles in nickel containing aerogels. On the other hand they do not affect the structure and size of the iron oxide nanoparticles in iron containing aerogels. The differences between the xerogel and aerogel nanocomposites are discussed.

Nickel oxide–silica and nickel–silica aerogel and xerogel nanocomposite materials

2000 ◽  
Vol 15 (10) ◽  
pp. 2187-2194 ◽  
Author(s):  
M. F. Casula ◽  
A. Corrias ◽  
G. Paschina
Keyword(s):  
Nickel Oxide ◽  
Sol Gel ◽  
Supercritical Drying ◽  
Nanocomposite Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
The Matrix ◽  
Drying Conditions ◽  
Microscopy Techniques

The sol-gel method was used to prepare nickel oxide–silica and nickel–silica nanocomposite materials and the corresponding silica matrices. Different drying conditions were used to obtain aerogel and xerogel materials. The samples were characterized by thermal analysis, x-ray diffraction, N2–physisorption, transmission electron microscopy techniques, and infrared spectroscopy. Aerogel samples had a much higher surface area than the xerogel samples; moreover, different supercritical drying conditions gave rise to a different porous structure, which influenced the size and distribution of the nanoparticles in the matrix.

Synthesis and characterization of nickel oxide nanoparticles by sol-gel technique

2020 ◽  
Author(s):  
Infantiya Stephen Grace ◽  
J. Vinola ◽  
Shubramaniyan Deepapriya ◽  
David Rodney John ◽  
A. Aslinjensipriya ◽  
...  
Keyword(s):  
Nickel Oxide ◽  
Sol Gel ◽  
Synthesis And Characterization ◽  
Oxide Nanoparticles ◽  
Nickel Oxide Nanoparticles ◽  
Gel Technique

Iron and Iron-oxide on Silica Nanocomposites Prepared by the Sol-gel Method

2002 ◽  
Vol 17 (3) ◽  
pp. 590-596 ◽  
Author(s):  
G. Ennas ◽  
M. F. Casula ◽  
G. Piccaluga ◽  
S. Solinas ◽  
M. P. Morales ◽  
...  
Keyword(s):  
Sol Gel ◽  
Silica Matrix ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Gel Method ◽  
Sol Gel Method ◽  
Silica Nanocomposites ◽  
Transmission Electron ◽  
Nanometric Particles

γ–Fe2O3/SiO2 and Fe/SiO2 nanocomposites, with a Fe/Si molar ratio of 0.25, were prepared by the sol-gel method starting from ethanolic solutions of tetraethoxysilane and iron (III) nitrate. After gelation the xerogels were oxidated or reduced. Samples were investigated by transmission electron microscopy, x-ray diffraction, differential scanning calorimetry, and thermogravimetry. Magnetic properties of the samples were investigated at room temperature (RT) and at 77 K. Nanometric particles supported in the silica matrix were obtained in all cases. Bigger particles (10 nm) were obtained in the case of Fe/SiO2 nanocomposites with respect to the γ–Fe2O3/SiO2 samples (5–8 nm). A slight effect of sol dilution on particle size was observed only in the case of γ–Fe2O3/SiO2 nanocomposites. A superparamagnetic behavior was shown at RT only by γ–Fe2O3/SiO2 nanocomposites. Iron-based composites exhibited coercivity values higher than 700 Oe at RT.

Structural Stability of Iron Oxide Nanotubes and an Enhancement of Photo Induced Current Detected in the Complex with Fullerenols

2014 ◽  
Vol 1659 ◽  
pp. 169-174 ◽  
Author(s):  
Shunji Bandow ◽  
Yuki Shiraki
Keyword(s):  
Iron Oxide ◽  
Sol Gel ◽  
Crystallographic Structure ◽  
X Ray Diffraction ◽  
Morphological Transformation ◽  
Diffraction Profile ◽  
Structure Changes ◽  
Transmission Electron ◽  
Inner Diameter ◽  
Gel Technique

ABSTRACTIron oxide nanotubes (Fe-ox-NTs) were prepared by a sol-gel technique using a mixture of an Fe(NO3)3·9H2O and a Pluronic F-127 nonionic surfactant in 1-propanol, gelatinizing at 35 °C for 5 days. Crude nanotubes thus obtained were well rinsed by deionized water in order to remove the surfactant. Transmission electron microscopy showed that the products have tubule structure with the outer (inner) diameter ∼10-15 (∼5-10) nm and the length ∼100 nm. X-ray diffraction profile of the crude nanotubes indicated a broadened feature characteristic for a defective or amorphous-like material, and whose profile may associate with the structure of ɣ-Fe2O3 (maghemite). By heating the crude nanotubes in open air, a phase transition occurs in a defective ɣ-Fe2O3 and its structure changes to a relaxed α-Fe2O3 (hematite) without morphological transformation. A further increase of the temperature results a destruction of the tube structure to the spherical nanoparticles without changing the crystallographic structure. A structurally relaxed Fe-ox-NT complex with fullerenols (C60(OH)n, n∼20) has larger photosensitive response under visible light irradiation, but the crude and defective Fe-ox-NTs and their complexes with fullerenols do not indicate noticeable response.

scholarly journals Characterization of Nickel Oxide Nanoparticles Synthesized under Low Temperature

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1168
Author(s):  
Sung-Jei Hong ◽  
Hyuk-Jun Mun ◽  
Byeong-Jun Kim ◽  
Young-Sung Kim
Keyword(s):  
Low Temperature ◽  
Nickel Oxide ◽  
Oxide Nanoparticles ◽  
X Ray Diffraction ◽  
Nickel Oxide Nanoparticles ◽  
Temperature Method ◽  
Bet Specific Surface Area ◽  
Heat Treated ◽  
Nio Nps ◽  
Xrd Patterns

In this study, ultrafine nickel oxide nanoparticles (NiO NPs) were well synthesized using a simple wet chemical method under low temperature, 300 °C. An Ni(OH)2 precursor was well precipitated by dropping NH4OH into an Ni(Ac)2 solution. TG-DTA showed that the weight of the precipitate decreases until 300 °C; therefore, the precursor was heat-treated at 300 °C. X-ray diffraction (XRD) patterns indicated that hexagonal-structured NiO NPs with (200) preferred orientation was synthesized. In addition, BET specific surface area (SSA) and HRTEM analyses revealed that spherical NiO NPs were formed with SSA and particle size of 60.14 m2/g and ca. 5–15 nm by using the low temperature method. FT-IR spectra of the NiO NPs showed only a sharp vibrating absorption peak at around 550 cm−1 owing to the Ni-O bond. Additionally, in UV-vis absorption spectra, the wavelength for absorption edge and energy band gap of the ultrafine NiO NPs was 290 nm and 3.44 eV.

scholarly journals Plant Extract Mediated Synthesis of Nickel Oxide Nanoparticles

2020 ◽  
Vol 2 (2) ◽  
pp. 205-209
Keyword(s):  
Fourier Transform ◽  
Nickel Oxide ◽  
Fourier Transform Infrared ◽  
Oxide Nanoparticles ◽  
X Ray Diffraction ◽  
Leaf Extracts ◽  
Nickel Oxide Nanoparticles ◽  
X Ray ◽  
Chloride Hexahydrate ◽  
Scanning Electron

The present study reports the successful synthesis of nickel oxide nanoparticles using Vernonia amygdalina plant leaf extracts as a chelating agent and nickel (II) chloride hexahydrate (NiCl2•6H2O) as precursor. The synthesized powder was gray black in color and annealed at 500 °C for 2 hours to obtain nickel oxide nanoparticles. Characterization techniques such as powder X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy were used to study the structure and morphology of the nanoparticles. Powder X-ray diffraction patterns revealed that nickel oxide nanoparticles with an average crystallite size of 17.86nm were synthesized. Scanning electron microscope images show that the nanoparticles have octahedral structure. Fourier transform infrared spectrophotometer analysis revealed that the strongest bond at 1094.8cm-1 corresponds to stretching vibration mode of Ni-O nanoparticles.

Characterization of Iron Oxide Nanoparticles for Sol-Gel Dip-Coating Method Prepared Thin Films

2013 ◽  
Vol 704 ◽  
pp. 275-280
Author(s):  
Janina Setina ◽  
Alona Gabrene ◽  
Inna Juhnevica ◽  
Gundars Mezinskis
Keyword(s):  
Thin Films ◽  
Iron Oxide ◽  
Iron Oxides ◽  
Sol Gel ◽  
Morphological Characteristics ◽  
Dip Coating ◽  
X Ray Diffraction ◽  
Coating Method ◽  
Dip Coating Method ◽  
Dip Coating Technique

The paper describes two methods of syntheses of iron oxides, microstructure and morphology of magnetite nanoparticles. Nanocomposite thin films of SiO2/Fe3O4 have been prepared with sol-gel dip coating technique: dip-coating from SiO2/Fe3O4 sol and encapsulation magnetite between two SiO2 layers. Structural and morphological characteristics of iron oxides particles and prepared film were analyzed by X-Ray Diffraction, SEM, FTIR, DTA, AFM. AFM topography of surface and measurements of roughness has shown that using iron oxide encapsulation between two SiO2 layers to provide the even distribution of iron oxide, results as high quality films with low Rq values 1.5 2.7 nm.

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