Preparation and Characterization of Alumina Nanoparticles from Alkoxides and Na (AOT) Surfactant

2007 ◽  
Vol 544-545 ◽  
pp. 785-788
Author(s):  
Yong Kap Park
Keyword(s):  
Surface Active Agent ◽  
Sol Gel ◽  
Active Agent ◽  
Precursor Solution ◽  
Phase Changes ◽  
Alumina Nanoparticles ◽  
Transmission Electron ◽  
Dsc Analyses ◽  
Size And Morphology ◽  
Α Al2o3

Nanosized α-aluminum oxides have been prepared by hydrolysis of aluminum alkoxides using a sol-gel procedure. The Na(AOT) as a surface active agent was added into the alumina precursor solution to investigate the influence on size and morphology of alumina particles. The product phase was mainly boehmite with mean particle size of 20~30 nm. The crystal phases and morphology of the alumina nanoparticles were analyzed by X-ray diffractometry and by transmission electron microscopy, respectively. The TEM observations revealed that α-Al2O3 with about 80 nm spherical and hexagonal shapes was formed after calcination at 1200oC. The TG/DSC analyses were also done to determine the phase changes of alumina precursors from room temperature to 1200oC.

Combined effect of grain size and tensile stresses on the ferroelectric properties of sol-gel (Pb,La)TiO3 thin films

1999 ◽  
Vol 14 (12) ◽  
pp. 4570-4580 ◽  
Author(s):  
M. Alguerá ◽  
M. L. Calzada ◽  
L. Pardo ◽  
E. Snoeck
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Size ◽  
Lead Titanate ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Precursor Solution ◽  
Grain Size Effect ◽  
Transmission Electron ◽  
Switchable Polarization

Transmission electron microscopy has shown that the grain size of sol-gel-prepared lanthanum-modified lead titanate films increases from ∼100 to ∼1 μm when the excess of PbO in the precursor solution is reduced from 20 to 10 mol%. Switchable polarization is higher in the films with a smaller grain size. Profilometry and the temperature dependence of the dielectric permittivity indicate that films are tensile stressed by the substrate. The grain-size effect on polarization switching is explainedby taking into account this tensile stress, which is thought to induce some a-domain orientation and 90° domain wall clamping in the grains attached to the substrate.

CuO-CoO-MnO/SiO2 Nanocomposite Aerogel as Catalysts Carrier and Its Cocatalysis Mechanism in the Synthesis of Diphenyl Carbonate

2011 ◽  
Vol 284-286 ◽  
pp. 707-710 ◽  
Author(s):  
Yue Qing Zhao ◽  
Qian Yi Jia ◽  
Ying Hua Liang ◽  
Hong Xia Guo ◽  
Feng Feng Li ◽  
...  
Keyword(s):  
Transition Metals ◽  
Surface Active Agent ◽  
Sol Gel ◽  
Active Agent ◽  
Supercritical Drying ◽  
Diphenyl Carbonate ◽  
Impregnation Method ◽  
Sol Gel Process ◽  
Surface Active

CuO-CoO-MnO/SiO2 nanocomposite aerogel as catalysts carrier was prepared via sol-gel process and CO2supercritical drying (SCD) technique. Catalyst supported by the nanocomposite aerogel was prepared via impregnation method. The catalyst was used for the synthesis of diphenyl carbonate (DPC), and the yield of DPC in mass is up to 26.31%. The catalysis system of PdCl2/Co(OAc)2-Cu(OAc)2-Mn(OAc)2/TBAB/H2BQ is favorable to the synthesis of DPC. PdCl2, acetates of transition metals and H2BQ were the key catalyst, inorganic cocatalyst and organic cocatalyst, respectively. TBAB was the surface active agent of Pd0and stabilizer of Pd2+in the catalysis system.

STUDY ON SYNTHESIS AND EVOLUTION OF NANOCRYSTALLINE Mg4Ta2O9 BY AQUEOUS SOL–GEL PROCESS

2012 ◽  
Vol 19 (03) ◽  
pp. 1250024 ◽  
Author(s):  
H. T. WU ◽  
C. H. YANG ◽  
W. B. WU ◽  
Y. L. YUE
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Sol Gel ◽  
Phase Evolution ◽  
Solid State Method ◽  
Conventional Solid State Method ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
State Method ◽  
Size And Morphology

Nanosized and highly reactive Mg4Ta2O9 were successfully synthesized by aqueous sol–gel method compared with conventional solid-state method. Ta-Mg-citric acid solution was first formed and then evaporated resulting in a dry gel for calcination in the temperature ranging from 600°C to 800°C for crystallization in oxygen atmosphere. The crystallization process from the gel to crystalline Mg4Ta2O9 was identified by thermal analysis and phase evolution of powders was studied using X-ray diffraction (XRD) technique during calcinations. Particle size and morphology were examined by transmission electron microscopy (TEM) and high resolution scanning electron microscopy (HR-SEM). The results revealed that sol–gel process showed great advantages over conventional solid-state method and Mg4Ta2O9 nanopowders with the size of 20–30 nm were obtained at 800°C.

Preparation of Ag Nanoparticles Colloid by Pulsed Laser Ablation in Distilled Water

2008 ◽  
Vol 373-374 ◽  
pp. 346-349 ◽  
Author(s):  
Bing Xu ◽  
Ren Guo Song ◽  
P.H. Tang ◽  
J. Wang ◽  
Guo Zhong Chai ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Ag Nanoparticles ◽  
Surface Active Agent ◽  
Active Agent ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Average Diameter ◽  
Distilled Water ◽  
Ablation Efficiency ◽  
Transmission Electron

The Ag nanoparticles colloid was prepared by pulsed laser ablation for different time in 10 ml distilled water without any surface active agent, and it was analysed by means of UV-visible spectrophotometer and transmission electron microscopy (TEM). The results showed that the ablation efficiency and absorbance increased fast and shift to higher energies with increasing ablation time from 5 to 10 min, then increased slowly from 10 to 20 min, and increased fast again from 20 to 25 min. The morphologies of most Ag nanoparticles were nearly spherical. The average diameter and its distribution decreased from 5 to 7.5 min, then increased from 7.5 to 15 min, and decreased from 15 to 25 min.

scholarly journals Characterization of LiCo Nanopowders Produced by Sol-Gel Processing

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Sina Soltanmohammad ◽  
Sirous Asgari
Keyword(s):  
Thermal Analyses ◽  
Sol Gel ◽  
Lithium Ion ◽  
Chelating Agent ◽  
Complexing Agents ◽  
Complexing Agent ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Size And Morphology ◽  
Gel Processing

LiCo nanopowders, one of the most important cathode materials for lithium-ion batteries, were synthesized via a modified sol-gel process assisted with triethanolamine (TEA) as a complexing agent. The influence of three different chelating agents including acrylic acid, citric acid, and oxalic acid on the size and morphology of particles was investigated. Structure and morphology of the synthesized powders were characterized by thermogravimetric/differential thermal analyses (TG/DTA), X-ray diffraction (XRD), and transmission electron microscopy (TEM). Results indicate that the powder processed with TEA and calcinated at 800 had an excellent hexagonal ordering of -NaFe-type (space group Rm). Also, the other three complexing agents had a decisive influence on the particle size, shape, morphology, and degree of agglomeration of the resulting oxides. Based on the data presented in this work, it is proposed that the optimized size and distribution of LiCo powders may be achieved through sol-gel processing using TEA as a chelating agent.

Preparation and Characterization of Monocrystal Nano-Sliver Lamella

2011 ◽  
Vol 399-401 ◽  
pp. 300-304
Author(s):  
Hai Lu Fan ◽  
Zhi Ping Liu ◽  
Shu Yi Chen
Keyword(s):  
Film Thickness ◽  
Diffraction Data ◽  
Surface Active Agent ◽  
Active Agent ◽  
Optical Path ◽  
Light Path ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
The Difference

Monocrystal nano-sliver lamella were prepared by hydrothermal method with the precursor Ag2C2O4and the surface active agent polyvinyl alcohol (PVA). The influence of the dosage of PVA on the film thickness and yield of nano-sliver lamella (NSL) were analyzed. And the morphology, the film thickness and electron diffraction pattern of NSL were characterized by scanning electron microscopy (SEM) and transmission electron microscope (TEM) respectively . Furthermore,the same sample was respectively characterized by the parallel optical path and the focus optical path of X-ray diffraction (XRD), and the difference between the diffraction data of these two paths was compared. The results show that the dosage of PVA has significant effect on the thickness and yield of monocrystal nano-sliver lamella. The reason that the great difference between diffraction data of the parallel light path and focusing light path can be mainly owing to the preferential orientation in space of NSL.

scholarly journals Self-Assembly of Au-Fe3O4 Hybrid Nanoparticles Using a Sol–Gel Pechini Method

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 6943
Author(s):  
Jesus G. Ovejero ◽  
Miguel A. Garcia ◽  
Pilar Herrasti
Keyword(s):  
Self Assembly ◽  
Pechini Method ◽  
Sol Gel ◽  
Reaction Times ◽  
Alkaline Media ◽  
Hybrid Nanoparticles ◽  
Self Assembling ◽  
Transmission Electron ◽  
Ir Transmission ◽  
Size And Morphology

The Pechini method has been used as a synthetic route for obtaining self-assembling magnetic and plasmonic nanoparticles in hybrid silica nanostructures. This manuscript evaluates the influence of shaking conditions, reaction time, and pH on the size and morphology of the nanostructures produced. The characterization of the nanomaterials was carried out by transmission electron microscopy (TEM) to evaluate the coating and size of the nanomaterials, Fourier-transform infrared spectroscopy (FT-IR) transmission spectra to evaluate the presence of the different coatings, and thermogravimetric analysis (TGA) curves to determine the amount of coating. The results obtained show that the best conditions to obtain core–satellite nanostructures with homogeneous silica shells and controlled sizes (<200 nm) include the use of slightly alkaline media, the ultrasound activation of silica condensation, and reaction times of around 2 hours. These findings represent an important framework to establish a new general approach for the click chemistry assembling of inorganic nanostructures.

The Preparation of Fe3O4 Magnetic Nanometer Particle by Co-Precipitation Method

2012 ◽  
Vol 271-272 ◽  
pp. 320-323
Author(s):  
Xiao Chun Ma ◽  
Lei Hao Cui ◽  
Guang Fei Xu
Keyword(s):  
Electron Microscopy ◽  
Surface Active Agent ◽  
Active Agent ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Surface Active ◽  
Co Precipitation ◽  
Nanometer Particle

In this paper, the Fe3O4 magnetic nanometer particle was prepared by co-precipitation method. At the same time, the samples were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that the surface active agent (PEG4000) can be good for the dispersion performance of Fe3O4 magnetic nanometer particle; and the temperature of 80°C is the appropriate drying temperature to prepare the Fe3O4 magnetic nanometer particle.

scholarly journals Surfactant Effects on the Synthesis of Redox Bifunctional V2O5 Photocatalysts

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4665
Author(s):  
Islam Ibrahim ◽  
George V. Belessiotis ◽  
Michalis K. Arfanis ◽  
Chrysoula Athanasekou ◽  
Athanassios I. Philippopoulos ◽  
...  
Keyword(s):  
Uv Light ◽  
Surface Active Agent ◽  
Active Agent ◽  
Precursor Solution ◽  
Tween 80 ◽  
Structural Defects ◽  
Light Illumination ◽  
Strong Impact ◽  
High Porosity ◽  
High Yields

Novel V2O5 bifunctional photocatalysts were prepared following a wet chemical process with the addition of anionic or non-ionic surfactants into the precursor solution and further heating under reflux. Detailed characterization and investigation of the relevant light-matter interactions proved that surfactants addition had a strong impact on the morphology, while also affecting the crystallinity, the optoelectronic properties, and the surface chemistry of the novel photocatalysts. The most efficient photocatalyst (T80) was based on tween 80, a surface-active agent employed for the first time in the synthesis of vanadium oxide materials. T80 presented crystalline nature without structural defects, which are usually centers of e− − h+ recombination. This material also exhibited small crystal size, high porosity, and short migration paths for the charge carriers, enabling their effective separation during photocatalysis. Under UV light illumination, T80 was capable to reduce hexavalent chromium to trivalent up to 70% and showed high yields in degrading methylene blue azo-dye and tetracycline antibiotic water pollutants. This remarkably high bifunctional performance defines T80 as a promising and capable photocatalytic material for both advanced oxidation and reduction processes (AOPs-ARPs).

scholarly journals Process for Producing Nano-Alpha-Alumina Powder

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Fatemeh Mirjalili ◽  
Luqman Chuah Abdullah ◽  
Hasmaliza Mohamad ◽  
A. Fakhru'l-Razi ◽  
A. B. Dayang Radiah ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Sol Gel ◽  
Alumina Nanoparticles ◽  
Alumina Powder ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Stirring Time ◽  
Particle Size And Shape

This paper is trying to explore the effect of stirring time on the synthesis of nano-α-Alumina particles. In this study, alumina nanoparticles were synthesized through alkoxide route using sol-gel method, where aqueous solutions of aluminum isopropoxide and 0.5 M aluminum nitrate nanohydrate were used for preparing alumina sol. Sodium dodecylbenzen sulfonate (SDBS) was used as the surfactant stabilizing agent. The prepared solution was stirred at different times (24, 36, 48, and 60 hours) at 60°C. The Samples were, then, characterized by X-ray diffraction, thermogravimetry analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and Transmission Electron Microscopy(TEM) . The introduction of different stirring times affected the particle size and shape and the degree of aggregation. By increasing the stirring time, (starting from 24 to 48 hours) the particle size decreased, but agglomeration became hard for 60 hours of stirring time. The finest particle size (20–30 nm) was obtained at 48-hour stirring time.

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