scholarly journals Synthesis and Photocatalytic Activity of Magnetically Recoverable Core-Shell Nanoparticles

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Zhen Peng ◽  
Hua Tang ◽  
Yao Tang ◽  
Ke Fu Yao ◽  
Hong Hong Shao
Keyword(s):  
Photocatalytic Activity ◽  
High Efficiency ◽  
Sol Gel ◽  
High Photocatalytic Activity ◽  
Core Shell ◽  
Oily Wastewater ◽  
Strong Response ◽  
Shell Nanoparticles ◽  
Oil Concentration ◽  
Core Shell Nanoparticles

TiO2/SiO2/Fe3O4(TSF) core-shell nanoparticles with good photocatalytic activity that are capable of fast magnetic separation have been successfully prepared by chemical coprecipitation and two-step sol-gel process. The as-prepared TSF nanoparticles were calcined at high temperature in order to transform the amorphous titanium dioxide into a photoactive crystalline phase. The calcined nanoparticles are composed of a Fe3O4core with a strong response to external magnetic fields, a SiO2intermediary layer, and a TiO2outshell. Vibration sample magnetometer (VSM) analysis confirms the superparamagnetism of calcined nanoparticles, which can enhance the recoverable properties of the novel photocatalyst. When the TiO2/SiO2/Fe3O4core-shell nanoparticles are added to the crude oily wastewater, they exhibit high photocatalytic activity in the degradation of crude oily wastewater. The oil concentration could be reduced to lower than 30 ppm within 20 minutes for the case of initial oil concentration less than 350 ppm. It has been found that the TSF nanoparticles could be easily separated from the wastewater and withdrawn by using an external magnetic field. The recovered TSF nanoparticles possess high efficiency in the degradation of crude oily wastewater even after three times successive reuse. The present results indicate that TSF core-shell nanoparticles possess great application perspectives in the degradation of crude oily wastewater.

scholarly journals Synthesis and Characterization of Silver/Titanium dioxide Core-Shell Nanoparticles

1970 ◽  
Vol 3 (1) ◽  
pp. 21-24
Author(s):  
Suk Fun Chin ◽  
Suh Cem Pang ◽  
Freda Emmanuel Idely Dom
Keyword(s):  
Photocatalytic Activity ◽  
Ag Nanoparticles ◽  
Sol Gel ◽  
Model Reaction ◽  
Synthesis And Characterization ◽  
Core Shell ◽  
Particle Sizes ◽  
Shell Nanoparticles ◽  
Core Shell Nanoparticles

Silver nanoparticles (AgNPs) with mean diameter of 150 nm were synthesized by using an aqueous-basedreduction method. Ascorbic acid and sodium hydroxide (NaOH) were used as a reducing agent and as acatalyst, respectively. These AgNPs were subsequently coated with a layer of TiO2 to form Ag/TiO2 core-shellnanoparticles by using a sol-gel method. The particle sizes and morphology of Ag/TiO2 core-shellnanoparticles were characterized using scanning electron microscopy (SEM) and transition electronmicroscopy (TEM). The photocatalytic activity of the Ag/TiO2 core-shell nanoparticles were evaluated basedon the degradation of methylene blue (MB) as the model reaction. The TiO2 coating has resulted in theenhanced photocatalytic activity of Ag nanoparticles as compared to bare Ag nanoparticles.

scholarly journals Fabrication of copper(II)-coated magnetic core-shell nanoparticles Fe3O4@SiO2-2-aminobenzohydrazide and investigation of its catalytic application in the synthesis of 1,2,3-triazole compounds

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
H. Rajabi-Moghaddam ◽  
M. R. Naimi-Jamal ◽  
M. Tajbakhsh
Keyword(s):  
High Efficiency ◽  
Click Reaction ◽  
Magnetic Core ◽  
Core Shell ◽  
Isatoic Anhydride ◽  
Shell Nanoparticles ◽  
Triazole Derivatives ◽  
Catalytic Application ◽  
Ft Ir ◽  
Core Shell Nanoparticles

AbstractIn the present work, an attempt has been made to synthesize the 1,2,3-triazole derivatives resulting from the click reaction, in a mild and green environment using the new copper(II)-coated magnetic core–shell nanoparticles Fe3O4@SiO2 modified by isatoic anhydride. The structure of the catalyst has been determined by XRD, FE-SEM, TGA, VSM, EDS, and FT-IR analyzes. The high efficiency and the ability to be recovered and reused for at least up to 6 consecutive runs are some superior properties of the catalyst.

scholarly journals PREPARATION OF CORE-SHELL SILVER/SILICA NANOPATICLES AND THEIR APPLICATION FOR ENHANCEMENT OF CYANINE 3 FLUORESCENCE

2012 ◽  
Vol 11 (04) ◽  
pp. 1240020 ◽  
Author(s):  
N. SUI ◽  
V. MONNIER ◽  
Z. YANG ◽  
Y. CHEVOLOT ◽  
E. LAURENCEAU ◽  
...  
Keyword(s):  
Steady State ◽  
Fluorescence Spectroscopy ◽  
Sol Gel ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Steady State Fluorescence ◽  
Covalently Bonded ◽  
Core Shell Nanoparticles ◽  
Steady State Fluorescence Spectroscopy ◽  
Silver Core

Core shell Ag@SiO2 -Streptavidin- Cy3 nanoparticles were prepared. Ag@SiO2 nanoparticles were synthesized via a sol–gel method. Then, Streptavidin- Cy3 was covalently bonded to the Ag@SiO2 surface. These core-shell nanoparticles were characterized by steady-state fluorescence spectroscopy and fluorescence scanning. In presence of the silver core, a 2.5-time enhancement of Cy3 fluorescence intensity was obtained. This result shows that these nanoparticles can be potentially helpful in surface analysis based on biochip.

Synthesis and Magnetic Properties of FePt Nanoparticles with Hard Nonmagnetic Shells

2007 ◽  
Vol 7 (1) ◽  
pp. 350-355 ◽  
Author(s):  
Shishou Kang ◽  
Shifan Shi ◽  
G. X. Miao ◽  
Zhiyong Jia ◽  
David E. Nikles ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Crystallographic Orientation ◽  
Sol Gel ◽  
Molar Ratio ◽  
Core Shell ◽  
Fept Nanoparticles ◽  
Shell Nanoparticles ◽  
Spherical Core ◽  
Size And Morphology ◽  
Core Shell Nanoparticles

Chemically synthesized FePt nanoparticles were coated with nonmagnetic SiO2 and MnO shells by sol–gel and polyol processes. TEM images show that the FePt/SiO2 nanoparticles exhibit a thick spherical shell. The size and morphology of the MnO shell can be controlled by changing the reaction temperature, the molar ratio of surfactants/Mn(acac)2, and/or the concentration of precursor. The morphology of the MnO shell can be either spherical-like or cubic-like, depending on whether the molar ratio of surfactants/Mn(acac)2 is less than or larger than 2. From XRD measurements, the spherical core/shell nanoparticles exhibit 3D random crystallographic orientation, while the cubic core/shell nanoparticles prefer (200) texture. The magnetic moment of FePt particles can be enhanced by coating with SiO2 and MnO shells. Furthermore, the agglomeration of FePt particles upon the thermal annealing can be significantly inhibited with SiO2 and MnO shells.

Preparation and characterization of sol–gel derived Er3+–Yb3+ codoped SiO2/TiO2 core–shell nanoparticles

2010 ◽  
Vol 64 (7) ◽  
pp. 846-848 ◽  
Author(s):  
Shujie Pang ◽  
Xianliang Li ◽  
Zuosen Shi ◽  
Guang Yang ◽  
Zhanchen Cui
Keyword(s):  
Sol Gel ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Core Shell Nanoparticles

scholarly journals High Photocatalytic Activity of Fe3O4-SiO2-TiO2Functional Particles with Core-Shell Structure

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Chenyang Xue ◽  
Qiang Zhang ◽  
Junyang Li ◽  
Xiujian Chou ◽  
Wendong Zhang ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Photocatalytic Activity ◽  
Shell Structure ◽  
Sol Gel ◽  
High Photocatalytic Activity ◽  
Core Shell ◽  
Large Area ◽  
Uniform Size ◽  
Functional Nanoparticles ◽  
Core Shell Structure

This paper describes a novel method of synthesizing Fe3O4-SiO2-TiO2functional nanoparticles with the core-shell structure. The Fe3O4cores which were mainly superparamagnetic were synthesized through a novel carbon reduction method. The Fe3O4cores were then modified with SiO2and finally encapsulated with TiO2by the sol-gel method. The results of characterizations showed that the encapsulated 700 nm Fe3O4-SiO2-TiO2particles have a relatively uniform size distribution, an anatase TiO2shell, and suitable magnetic properties for allowing collection in a magnetic field. These magnetic properties, large area, relative high saturation intensity, and low retentive magnetism make the particles have high dispersibility in suspension and yet enable them to be recovered well using magnetic fields. The functionality of these particles was tested by measuring the photocatalytic activity of the decolouring of methyl orange (MO) and methylene blue (MB) under ultraviolet light and sunlight. The results showed that the introduction of the Fe3O4-SiO2-TiO2functional nanoparticles significantly increased the decoloration rate so that an MO solution at a concentration of 10 mg/L could be decoloured completely within 180 minutes. The particles were recovered after utilization, washing, and drying and the primary recovery ratio was 87.5%.

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