Influence of Various Reaction Parameters on the Process for Preparation of SiO2/TiO2 Core-Shell Particles

2015 ◽  
Vol 33 ◽  
pp. 27-37 ◽  
Author(s):  
Jhin Hong You ◽  
Yi Yin Kuo ◽  
Keh Ying Hsu
Keyword(s):  
Inorganic Compounds ◽  
Sol Gel ◽  
Chelating Agent ◽  
Condensation Process ◽  
Infrared Analysis ◽  
Ionic Surfactant ◽  
Core Shell ◽  
Reaction Parameters ◽  
The Core ◽  
Shell Particles

This study aims to describe the preparation and characterization of SiO2/TiO2 core-shell particles. In order to prepare the homogenous SiO2/TiO2 inorganic compounds by sol-gel process, SiO2 particles were used as the core, AcAc served as a chelating agent to chelate with TTIP (which was used as the precursor to TiO2), and PEG was added to stabilize the hydrolysis/condensation process. In addition, the ionic surfactant (SDS) and the nonionic surfactant (PVP) dispersed the core-shell particles. In order to improve the crystal structure, a high temperature was used to calcine the core-shell particles. The influence of various reaction parameters on the size, morphology and composition of the particles was also investigated. The properties of the particles were analyzed by electron microscopy, fourier transform infrared analysis, thermogravimetric analysis and powder X-ray diffraction.

Synthesis and Photoluminescence Properties of Monodisperse Spherical SiO2@Lu2O3: Eu3+ Particles with Core-Shell Structure

2014 ◽  
Vol 1004-1005 ◽  
pp. 389-392
Author(s):  
Huan Wang
Keyword(s):  
Smooth Surface ◽  
Sol Gel ◽  
Spherical Shape ◽  
Core Shell ◽  
Narrow Size Distribution ◽  
Photoluminescence Properties ◽  
The Core ◽  
Sol Gel Process ◽  
Core Shell Structure ◽  
Shell Particles

Spherical submicron SiO2 particles have been coated with luminescent Lu2O3: Eu3+ layers by a Pechini sol-gel process, resulting in the formation of SiO2@Lu2O3: Eu3+ core-shell particles(300, 500 nm). The obtained core–shell phosphors have perfect spherical shape with narrow size distribution, smooth surface and non-agglomeration. The thickness of shells could be easily controlled by changing the number of deposition cycles (50 nm for four deposition cycles). Under the excitation of ultraviolet, the Eu3+ ion mainly shows its characteristic emissions in the core-shell particles from Lu2O3: Eu3+) shells. The PL intensity of Eu3+ increases with the number of coating cycles.

Synthesis and Characterization of Monodisperse Spherical SiO2@Y2O3: Tb3+ Particles with Core-Shell Structure

2014 ◽  
Vol 997 ◽  
pp. 317-320 ◽  
Author(s):  
Huan Wang ◽  
Ya Bing Liu ◽  
Ling Wei Kong
Keyword(s):  
Smooth Surface ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Spherical Shape ◽  
Core Shell ◽  
The Core ◽  
Sol Gel Process ◽  
Shell Particles ◽  
Average Size

Spherical submicron SiO2 particles have been coated with luminescent Y2O3: Tb3+ layers by a Pechini sol-gel process, resulting in the formation of SiO2@Y2O3: Tb3+ core-shell particles. The obtained core–shell phosphors have perfect spherical shape with narrow size distribution (average size ca. 450 nm), smooth surface and non-agglomeration. The thickness of shells could be easily controlled by changing the number of deposition cycles (35 nm for two deposition cycles). Under the excitation of ultraviolet, the Tb3+ ion mainly shows its characteristic emissions in the core-shell particles from Y2O3: Tb3+) shells. The emission intensity of Tb3+ can be tuned by the annealing temperature and the number of coating cycles.

Magnetic Properties of Fe3O4/CoFe2O4 Composite Nanoparticles with Core/Shell Architecture

2020 ◽  
Vol 65 (10) ◽  
pp. 904
Author(s):  
V. O. Zamorskyi ◽  
Ya. M. Lytvynenko ◽  
A. M. Pogorily ◽  
A. I. Tovstolytkin ◽  
S. O. Solopan ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Spinel Ferrite ◽  
Composite Nanoparticles ◽  
Core Shell ◽  
Cofe2o4 Nanoparticles ◽  
Core Diameter ◽  
The Core ◽  
Shell Particles ◽  
Interface Parameters ◽  
Shell Composite

Magnetic properties of the sets of Fe3O4(core)/CoFe2O4(shell) composite nanoparticles with a core diameter of about 6.3 nm and various shell thicknesses (0, 1.0, and 2.5 nm), as well as the mixtures of Fe3O4 and CoFe2O4 nanoparticles taken in the ratios corresponding to the core/shell material contents in the former case, have been studied. The results of magnetic research showed that the coating of magnetic nanoparticles with a shell gives rise to the appearance of two simultaneous effects: the modification of the core/shell interface parameters and the parameter change in both the nanoparticle’s core and shell themselves. As a result, the core/shell particles acquire new characteristics that are inherent neither to Fe3O4 nor to CoFe2O4. The obtained results open the way to the optimization and adaptation of the parameters of the core/shell spinel-ferrite-based nanoparticles for their application in various technological and biomedical domains.

Fe@C core–shell and Fe@C yolk–shell particles for effective removal of 4-chlorophenol

2015 ◽  
Vol 3 (7) ◽  
pp. 3988-3994 ◽  
Author(s):  
Xiang Li ◽  
Fangyuan Gai ◽  
Buyuan Guan ◽  
Ye Zhang ◽  
Yunling Liu ◽  
...  
Keyword(s):  
Carbon Shell ◽  
Core Shell ◽  
The Core ◽  
Effective Removal ◽  
Shell Particles

Fe@C yolk–shell particles were synthesized by reducing the core with its own carbon shell to achieve the effective removal of 4-chlorophenol from water.

Effect of glycidyl methacrylate (GMA) on the stability of acrylic latex

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Guangfeng Wu ◽  
Yue Tao ◽  
Hong Kang ◽  
Huixuan Zhang
Keyword(s):  
Experimental Data ◽  
Glycidyl Methacrylate ◽  
Sodium Dodecyl ◽  
The Other ◽  
Lower Amount ◽  
Core Shell ◽  
Acrylic Latex ◽  
The Core ◽  
Shell Particles ◽  
The Stability

AbstractThe stability of core-shell particles (CSPs) with butyl acrylate (BA) as the core and methyl methacrylate (MMA)/glycidyl methacrylate (GMA) mixture in various compositions as the shell was investigated by turbidity measurements. The experiments demonstrate that lower amount addition of GMA could not improve the latex stability. When the amount of GMA exceeded 2% of the total reactants, it began to improve the stability of the latex. With the increasing content of GMA, the latex became more and more stable. On the other hand, experimental data also show that the stability was improved by increasing the concentration of sodium dodecyl sulfate (SDS).

The Preparation of Core/Shell Particles with Siloxane in the Shell

2005 ◽  
Vol 13 (7) ◽  
pp. 721-726
Author(s):  
Shunsheng Cao ◽  
Xiaobo Deng ◽  
Bailing Liu
Keyword(s):  
Dispersion Medium ◽  
Average Diameter ◽  
Butyl Methacrylate ◽  
Core Shell ◽  
The Core ◽  
Transmission Electron ◽  
Seeding Method ◽  
Emulsion Polymerisation ◽  
Shell Particles ◽  
Methacryloxypropyl Trimethoxysilane

Core-shell microspheres ranging in average diameter from 12.829 to 15.039 μm, with a poly butyl methacrylate (BMA) core, and a poly 3-(methacryloxypropyl)-trimethoxysilane (MATS) shell, were prepared with methanol as the dispersion medium, by a successive seeding method under kinetically controlled conditions. To date, although some of particles (PSi/PA) have been prepared by seeded emulsion polymerisation, only a few core/shell (PA/PSi) microspheres have been reported the literatures. To prepare core/shell (PA/PSi), the core was first synthesized by dispersion polymerisation and to form seeds; addition of MATS monomer was started after 90~95% conversion of the BMA. The reaction was prolonged for another 12 h to achieve complete consumption of MATS monomer. Microspheres; containing hydrophilic PBMA as the core and hydrophobic PMATS as the shell, were successfully formed through the free radical of surface in the core. The particles morphology and size distribution were examined using a Transmission electron microscope and a Malvern Master Sizer/E particle size analyser, respectively.

Preparation and Characterization of Core-Shell Latex Containing PDMS in the Shell

e-Polymers ◽  
2006 ◽  
Vol 6 (1) ◽  
Author(s):  
Baotan Zhang ◽  
Bailing Liu ◽  
Shunsheng Cao ◽  
Xiaobo Deng
Keyword(s):  
Photoelectron Spectroscopy ◽  
Hydrophobic Surface ◽  
Water Repellency ◽  
Atomic Ratio ◽  
Core Shell ◽  
Seeded Emulsion Polymerization ◽  
The Core ◽  
Static Contact ◽  
Ft Ir ◽  
Shell Particles

AbstractIn this paper, the composite latex particles with a polyacrylate (PA) core and a polydimethylsiloxane (PDMS) shell via 3-(methacryloxypropyl)- trimethoxy silane (MPS) as the medium to link the core and shell were prepared by semicontinuous seeded emulsion polymerization and were characterized by transmission electron microscopy (TEM), FT-IR, particle size analyzer and X-ray photoelectron spectroscopy (XPS). The TEM images indicated that the particles containing organic siloxane (D-40) displayed an evident core/shell structure. Additionally, the study by FT-IR and XPS also revealed that D4 could be grafted onto the surface of polyacrylate core because there appeared the characteristic peaks of Si-O-Si group and Si 2s and Si 2p in the spectra of FT-IR and XPS respectively. Besides, the atomic ratio of C/Si on the surface of the core/shell particles (D-40) was close to the ratio of C/Si in the latex of pure PDMS that could prove the PA particles were fully covered by PDMS and the properties of PDMS should be embodied in a maximal level. In order to testify the result, the surface properties of the films produced from the core/shell particles were also investigated by the static contact angle method. Compared with the copolymer of PA, the core/shell particles were more effective to create hydrophobic surface, so, the introduction of D4 was capable of obvious increase in water repellency.

Sol-gel Synthesis and Characterization of Zn[sub 2]SiO[sub 4]:Mn@SiO[sub 2] Spherical Core-Shell Particles

2005 ◽  
Vol 152 (9) ◽  
pp. H146 ◽  
Author(s):  
D. Y. Kong ◽  
M. Yu ◽  
C. K. Lin ◽  
X. M. Liu ◽  
J. Lin ◽  
...  
Keyword(s):  
Sol Gel ◽  
Synthesis And Characterization ◽  
Core Shell ◽  
Spherical Core ◽  
Shell Particles ◽  
Sol Gel Synthesis

scholarly journals Мёссбауэровские исследования состава и магнитной структуры нанокомпозитов Fe-=SUB=-3-=/SUB=-O-=SUB=-4-=/SUB=-/γ-Fe-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=- типа ядро-оболочка во внешнем магнитном поле (Часть 2)

2020 ◽  
Vol 62 (11) ◽  
pp. 1919
Author(s):  
А.С. Камзин ◽  
I.M. Obaidat ◽  
А.А. Валлиулин ◽  
В.Г. Семенов ◽  
I.A. Al-Omari
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Spin Structure ◽  
Magnetic Moments ◽  
Core Shell ◽  
Fe2o3 Nanoparticles ◽  
Synthesis Conditions ◽  
The Core ◽  
Canted Spin ◽  
Shell Particles

The results of Mössbauer studies of the composition and magnetic structure of Fe3O4 / -Fe2O3 nanoparticles placed in an external magnetic field with a strength of 1.8 kOe, which is a continuation of the work [A.S. Kamzin, I.M. Obaidat, A.A. Valliulin, V.G. Semenov, I.A. Al-Omari. FTT No. 10/2020]. It is shown that the thickness of the maghemite (-Fe2O3) shell can be changed by the synthesis conditions. It was found that on the surface of the maghemite (-Fe2O3) shell in the Fe3O4 / -Fe2O3 nanocomposites there is a layer in which the magnetic moments are not oriented collinearly to the moments located in the depth of the shell, i.e., there is a canted spin structure. An intermediate layer in the spin-glass state is formed between the core and the shell. The data obtained on the structure of core / shell particles are important for understanding the properties of nanocomposites, which are of great interest for applications in various fields, including biomedicine.

scholarly journals The Effect of the ZrO2 Loading in SiO2@ZrO2-CaO Catalysts for Transesterification Reaction

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 221
Author(s):  
Daniela Salinas ◽  
Sichem Guerrero ◽  
Cristian H. Campos ◽  
Tatiana M. Bustamante ◽  
Gina Pecchi
Keyword(s):  
Sol Gel ◽  
Core Shell ◽  
Tem Analysis ◽  
Basic Sites ◽  
The Core ◽  
Surface Areas ◽  
Transmission Electron ◽  
Temperature Programmed ◽  
The Fourier Transform ◽  
Sio2 Spheres

The effect of the ZrO2 loading was studied on spherical SiO2@ZrO2-CaO structures synthetized by a simple route that combines the Stöber and sol-gel methods. The texture of these materials was determined using SBET by N2 adsorption, where the increment in SiO2 spheres’ surface areas was reached with the incorporation of ZrO2. Combined the characterization techniques of using different alcoholic dissolutions of zirconium (VI) butoxide 0.04 M, 0.06 M, and 0.08 M, we obtained SiO2@ZrO2 materials with 5.7, 20.2, and 25.2 wt % of Zr. Transmission electron microscopy (TEM) analysis also uncovered the shape and reproducibility of the SiO2 spheres. The presence of Zr and Ca in the core–shell was also determined by TEM. X-ray diffraction (XRD) profiles showed that the c-ZrO2 phase changed in to m-ZrO2 by incorporating calcium, which was confirmed by Raman spectroscopy. The purity of the SiO2 spheres, as well as the presence of Zr and Ca in the core–shell, was assessed by the Fourier transform infrared (FTIR) method. CO2 temperature programmed desorption (TPD-CO2) measurements confirmed the increment in the amount of the basic sites and strength of these basic sites due to calcium incorporation. The catalyst reuse in FAME production from canola oil transesterification allowed confirmation that these calcium core@shell catalysts turn out to be actives and stables for this reaction.

Sign in / Sign up

Export Citation Format

Share Document