Zinc Oxide Nanoparticles-Immobilized Mesoporous Hollow Silica Spheres for Photodegradation of Sodium Dodecylbenzenesulfonate

2016 ◽  
Vol 69 (7) ◽  
pp. 790 ◽  
Author(s):  
Parisa Pourdayhimi ◽  
Pei Wen Koh ◽  
Mohamed Mohd Salleh ◽  
Hadi Nur ◽  
Siew Ling Lee
Keyword(s):  
Mesoporous Structure ◽  
Molar Ratio ◽  
Silica Spheres ◽  
Transmission Electron Microscopy Analysis ◽  
Sodium Dodecylbenzenesulfonate ◽  
Hollow Silica ◽  
Hollow Silica Spheres ◽  
Transmission Electron ◽  
Electron Microscopy Analysis ◽  
Adsorption Desorption

ZnO-Immobilized mesoporous hollow silica spheres (ZnO/xMHSS; x = 15, 30, 50 molar ratio of Zn/Si) were synthesized and examined as photocatalysts toward the degradation of sodium dodecylbenzenesulfonate (SDBS). The hollow structures of MHSS and ZnO-immobilized MHSS composite were evidenced by transmission electron microscopy analysis. X-ray diffraction results confirmed the presence of ZnO and a mesoporous structure in the synthesized materials. N2 adsorption–desorption analysis also depicted the formation of a mesoporous structure and the increased surface area for the ZnO/xMHSS materials. Fourier transform infrared spectroscopy analysis revealed the formation of Si–O–Zn bonds due to interaction between ZnO and MHSS. The photocatalytic testing results indicated that all the ZnO/xMHSS materials showed improved efficiencies of 10–21 % toward the photodegradation of SDBS when compared with bare ZnO. Among the prepared materials, ZnO/15MHSS was the best photocatalyst, which photodegraded 68 % SDBS after 1 h reaction. The kinetic study demonstrated that the photocatalytic reaction followed the second-order model.

Synthesis and Enhanced Electromagnetic Wave Absorption Properties of Fe3O4@ZnO Mesoporous Spheres

2014 ◽  
Vol 1663 ◽  
Author(s):  
Danping Sun ◽  
Wei Jiang ◽  
Yanping Wang ◽  
Chen Sun ◽  
Quan Zou ◽  
...  
Keyword(s):  
Mesoporous Structure ◽  
Absorption Properties ◽  
Transmission Electron Microscopy Analysis ◽  
Absorption Frequency ◽  
Wave Absorption ◽  
Type Iv ◽  
Zno Nanocrystals ◽  
Transmission Electron ◽  
Electron Microscopy Analysis ◽  
Adsorption Desorption

ABSTRACTMesoporous Fe3O4 nanoparticles coated with ZnO nanocrystals were successfully synthesized by a simple solution method at low temperature. The transmission electron microscopy analysis indicates that the mesoporous Fe3O4 nanoparticles are monodispersed with a mean diameter of 160 nm and the thickness of ZnO layer is 15 nm approximately. The porosity of the products was further substantiated by the nitrogen (N2) sorption measurement. The N2 adsorption-desorption isotherm curve can be identified as type IV, which is a characteristic of mesopores. Electromagnetic (EM) wave absorption properties of the as-prepared Fe3O4@ZnO mesoporous spheres-wax composites were investigated at a room temperature in the frequency range of 0.5∼18 GHz. Interestingly, the Fe3O4@ZnO mesoporous spheres exhibit an enhanced EM wave absorption due to the mesoporous structure. The multiple absorbing mechanisms result from the interface polarization induced by the special core/shell and mesoporous structures as well as dipole polarization of both Fe3O4 and ZnO. The results demonstrate that the Fe3O4@ZnO mesoporous spheres are attractive candidates for a new kind of EM wave absorption materials with wide absorption frequency band.

Highly Crystalline Zinc Oxide/Mesoporous Hollow Silica Composites Synthesized at Low Temperature for the Photocatalytic Degradation of Sodium Dodecylbenzenesulfonate

2019 ◽  
Vol 72 (4) ◽  
pp. 252 ◽  
Author(s):  
Parisa Pourdayhimi ◽  
Pei Wen Koh ◽  
Hadi Nur ◽  
Siew Ling Lee
Keyword(s):  
Electron Microscopy ◽  
Mesoporous Structure ◽  
High Photocatalytic Activity ◽  
Impregnation Method ◽  
Transmission Electron Microscopy Analysis ◽  
Sodium Dodecylbenzenesulfonate ◽  
Hollow Silica ◽  
Molar Ratios ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis

Highly crystalline ZnO/mesoporous hollow silica sphere (MHSS) composites have been successfully synthesized through an impregnation method at 323K without applying calcination. Three composites of different Zn/Si molar ratios of 1:2, 1:1, and 2:1 were prepared. X-Ray diffraction patterns confirmed the presence of highly crystalline ZnO in the materials. A layer of ZnO was formed on the MHSS as evidenced by field emission scanning electron microscopy analysis. Transmission electron microscopy analysis verified the mesoporous structure in ZnO/MHSS composites. N2 adsorption–desorption analysis indicated a type IV isotherm for 1ZnO/2MHSS and 1ZnO/1MHSS samples, confirming the presence of mesopores in the ZnO layer. It has been demonstrated that all the ZnO/MHSS composites exhibit a high photocatalytic activity towards sodium dodecylbenzenesulfonate degradation compared with bare ZnO under UV irradiation. A kinetic study showed that the photodegradation followed a second order model. Among the prepared composites, 1ZnO/1MHSS recorded the highest reaction rate of 6.03×10−3mM−1min−1 which is attributed to a high crystallinity and the monodispersity of a high amount of ZnO on MHSS.

Preparation and Characterization of Hollow Silica Nanospheres

2011 ◽  
Vol 393-395 ◽  
pp. 240-243 ◽  
Author(s):  
Li Li Feng ◽  
Wei Zhao ◽  
Jing Jing Tong ◽  
Guan Hua Yue
Keyword(s):  
Electron Microscopy ◽  
Nitrogen Adsorption ◽  
Silica Shell ◽  
Silica Spheres ◽  
Silica Nanospheres ◽  
Hollow Silica ◽  
Hollow Silica Spheres ◽  
Transmission Electron ◽  
Hollow Silica Nanospheres

Monodisperse hollow silica nanospheres were prepared using functionalized polystyrene (PS) as a template and characterized by transmission electron microscopy (TEM), nitrogen adsorption and thermo gravimetry (TG) techniques. The effect of ammonia amount on hollow silica spheres was explored. It is found that the ammonia amount is important to the fabrication of hollow silica nanospheres. The roughness and thickness of the silica shell increased with the increase of ammonia amount. When ammonia amount reached 20 ml, the product hadn’t been hollow structural. The TGA curves and the BET results of the samples supplied a proof for the formation mechanism of the hollow silica spheres.

One-Pot Pathway: Fabricating Ordered Hollow Silica Spheres Using Sodium Silicate as the Precursor

2011 ◽  
Vol 64 (12) ◽  
pp. 1541 ◽  
Author(s):  
Weiwei Wu ◽  
Xinhua Yuan ◽  
Shunsheng Cao ◽  
Yi Ge ◽  
Songjun Li ◽  
...  
Keyword(s):  
Sodium Silicate ◽  
Low Cost ◽  
Reaction System ◽  
Silica Spheres ◽  
One Pot ◽  
Hollow Silica ◽  
Hollow Silica Spheres ◽  
Silica Source ◽  
Transmission Electron ◽  
Cationic Monomer

The preparation of hollow silica spheres via the sodium silicate route presents many advantages such as a low-cost silica source, and an environmentally friendly reaction system. Unfortunately, it is extremely hard to prepare the well-defined hollow silica spheres by using sodium silicate as the silica source owing to its rapid, disordered precipitation under the acid catalysis. As a result, we, in this paper, report a facile, economic, one-pot pathway for preparation of the ordered hollow silica spheres by employing a sodium silicate precursor. In this approach, the cationic polystyrene (CPS) templates can be first prepared via emulsifier-free emulsion polymerization by using the cationic monomer vinylbenzyltrimethylammonium chloride, then, the silica shells were attached on the surfaces of CPS particles via electrostatic interaction, finally CPS particles were in situ dissolved and removed by adding toluene to create ordered hollow silica spheres. Some modern techniques and instruments, including the transmission electron microscope, scanning electron microscopy, infrared spectroscopy, thermogravimetric analysis, and Brunauer-Emmett-Teller theory were employed to monitor and characterize the resulting hollow silica spheres.

Effect of hollow silica spheres on water vapor permeability of polyacrylate film

RSC Advances ◽  
2015 ◽  
Vol 5 (15) ◽  
pp. 11485-11493 ◽  
Author(s):  
Yan Bao ◽  
Chunhua Shi ◽  
Yongqiang Yang ◽  
Jianzhong Ma ◽  
Risong Sha
Keyword(s):  
Electron Microscopy ◽  
Shell Thickness ◽  
Water Vapor Permeability ◽  
Vapor Permeability ◽  
Silica Spheres ◽  
X Ray Diffraction ◽  
Hollow Silica ◽  
X Ray ◽  
Hollow Silica Spheres ◽  
Transmission Electron

Hollow silica spheres with different hollow size and shell thickness were synthesized via a template method using PS spheres as templates and characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction and Brunauer–Emmett–Teller analysis.

CHARACTERIZATION AND ELECTRICAL PROPERTIES OF ALIGNED CARBON NANOTUBES WITH HIGH ASPECT RATIO

2011 ◽  
Vol 10 (01n02) ◽  
pp. 23-28
Author(s):  
RAVI BHATIA ◽  
V. PRASAD ◽  
M. REGHU
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Aspect Ratio ◽  
Multiwall Carbon Nanotubes ◽  
High Quality ◽  
Transmission Electron Microscopy Analysis ◽  
Transmission Electron ◽  
Electron Microscopy Analysis ◽  
High Degree

High-quality multiwall carbon nanotubes (MWNTs) were produced by a simple one-step technique. The production of MWNTs was based on thermal decomposition of the mixture of a liquid phase organic compound and ferrocene. High degree of alignment was noticed by scanning electron microscopy. The aspect ratio of as-synthesized MWNTs was quite high (more than 4500). Transmission electron microscopy analysis showed the presence of the catalytic iron nanorods at various lengths of MWNTs. Raman spectroscopy was used to know the quality of MWNTs. The ratio of intensity of the G-peak to the D-peak was very high which revealed high quality of MWNTs. Magnetotransport studies were carried out at low temperature and a negative MR was noticed.

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