A CHITOSAN TEMPLATED SYNTHESIS OF BIMODAL POROUS SILICA

2012 ◽  
Vol 11 (06) ◽  
pp. 1240042
Author(s):  
NANZHE JIANG ◽  
CHENGBIN LI ◽  
SHIJUAN CHEN ◽  
GUANGXUE LIU ◽  
WAN MENG
Keyword(s):  
Electron Microscope ◽  
Size Distribution ◽  
Hybrid Composites ◽  
Porous Silica ◽  
Sodium Metasilicate ◽  
High Specific Surface Area ◽  
Narrow Pore Size Distribution ◽  
Transmission Electron ◽  
Adsorption Desorption ◽  
Hydrolysis Of

Biopolymer chitosan templated bimodal porous silica materials with uniform macroporosity and narrowed mesopore size distribution were synthesized via fast precipitation of chitosan–silica hybrid composites (Chi/ SiO2 ). Clear Chi/ SiO2 solutions containing the biopolymer chitosan and siloxane-based inorganic network were prepared by hydrolysis of sodium metasilicate in the presence of biopolymer chitosan. The relative amount of chitosan in as-made Chi/ SiO2 was analyzed by thermogravimetric analysis (TGA). Chi/ SiO2 was calcined at 600°C for 5 h in the presence air to remove chitosan, and characterized by scanning electron microscope (SEM), transmission electron microscope (TEM) and N2 adsorption–desorption isotherms. These porous silica products had high specific surface area of 500–550 m2/g, narrow pore size distribution and also bicontinuous macropore structure.

Silica Encapsulated CdS Tabular Nanocomposites via a Template Directed Agglomeration Mechanism

2008 ◽  
Vol 8 (11) ◽  
pp. 5878-5886 ◽  
Author(s):  
Jun Wang ◽  
Stephen J. Sollenberger ◽  
Ying Yuan ◽  
Timothy J. Yosenick ◽  
James H. Adair
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Coating Layer ◽  
Layer Growth ◽  
Cds Nanoparticles ◽  
Atomic Force ◽  
Transmission Electron ◽  
Potential Applications ◽  
Hydrolysis Of

Silica coated CdS tabular nanocomposites were synthesized through precipitation of CdS nanoparticles in octylamine/water bilayer system followed by in situ hydrolysis of tetraethoxylsilicate (TEOS) precursor. Face diameter of the nanoplatelets was in the range of 50∼250 nm with a variable thickness (3 to 25 nm) dictated by octylamine content or R ratio ([water]/[octylamine]). A uniform SiO2 outer shell of about 15 nm was observed regardless of the size of the high aspect ratio CdS nanoplatelets, which appeared to be agglomerated primarily owing to the confined bilayer template. Morphology and microstructure of the CdS/SiO2 tabular nanocomposites were characterized using atomic force microscope (AFM) and high resolution transmission electron microscope (HRTEM). A noticeable enhancement in absorbance for the UV-vis spectra was observed due to the SiO2 coating layer. Growth mechanism of nanocomposite platelets and potential applications associated with this anisotropic nanocomposite are discussed.

Fabrication of Hydroxyapatite and Observation of Nanoparticles Entering into Cells

2011 ◽  
Vol 366 ◽  
pp. 451-455 ◽  
Author(s):  
Dong Yang ◽  
En Jie Sun
Keyword(s):  
Electron Microscope ◽  
Zeta Potential ◽  
Size Distribution ◽  
Transmission Electron Microscope ◽  
Living System ◽  
Inorganic Nanoparticles ◽  
Transmission Electron

Unambiguous and thorough knowledge of interactions between cells and nanoparticles was necessary for applications of nanoparticle in living system. In this report we presented systematic studies of fabrication of inorganic nanoparticles and the application of entering into cells. Size distribution, zeta potential and transmission electron microscope (TEM) were performed to characterize the nanoparticles structure and define the mechanism by which nanoparticles are capable of entering into cells. The study revealed nanoparticles can entered cells via penetrating through the lipophilic bilayer, which should be paid attention to for inspirational value insome application researches and will be harmful in other cases.

Theory of Nuclear Relaxation in Confining Systems. Application to Non Wetting Liquids in Porous Silica Glasses

1992 ◽  
Vol 290 ◽  
Author(s):  
J.-P. Korb ◽  
A. Delville ◽  
Shu Xu ◽  
J. Jonas
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Sol Gel ◽  
Porous Silica ◽  
Nuclear Relaxation ◽  
Narrow Pore Size Distribution ◽  
Silica Glasses ◽  
Frequency Dependences ◽  
Wetting Liquid

AbstractThis work shows how the geometrical confinements enhances the nuclear relaxation of a non wetting liquid in a model porous systems. Application of the proposed theory is made to interpret the size and frequency dependences of the 1H relaxation of methylcyclohexane liquid in sol-gel porous silica glasses with narrow pore-size distribution.

A Facile Template Approach for Preparing Microstructures of Bimodal Crystalline Mesoporous Titania Powders

2012 ◽  
Vol 616-618 ◽  
pp. 1797-1800
Author(s):  
Yu Mei Gong ◽  
Qing Liang ◽  
Jing Chuan Song ◽  
Ling Ming Xia
Keyword(s):  
Electron Microscope ◽  
Surface Area ◽  
Nitrogen Adsorption ◽  
Mesoporous Titania ◽  
Mass Ratio ◽  
X Ray Diffraction ◽  
Average Pore ◽  
X Ray ◽  
Transmission Electron ◽  
Adsorption Desorption

This paper presents the preparation of bimodal crystalline macro-/mesoporous titania powders by using a pluronic polymer (EO20PO70EO20, P123) as a template through a hydrothermal treatment. The as-prepared powders were characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption, scanning electron microscope (SEM) and transmission electron microscope (TEM). The results reveal that the amount of P123 has a significant effect on the surface area of the mesoporous titania. When the mass ratio of P123:TBOT is 1:14, the crystalline macro-/mesoporous titania has the largest surface area (120.96 m2/g), the average pore diameter of this sample reaches a minimum of 6.67 nm.

scholarly journals Highly Reducible Nanostructured CeO2 for CO Oxidation

Catalysts ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 535 ◽  
Author(s):  
Gang Feng ◽  
Weining Han ◽  
Zhimiao Wang ◽  
Fang Li ◽  
Wei Xue
Keyword(s):  
Electron Microscope ◽  
Co Oxidation ◽  
Hydrothermal Process ◽  
Textural Properties ◽  
Space Velocity ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Co Conversion ◽  
Structure Morphology ◽  
Adsorption Desorption

Ceria in nanoscale with different morphologies, rod, tube and cube, were prepared through a hydrothermal process. The structure, morphology and textural properties were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and isothermal N2 adsorption-desorption. Ceria with different morphologies were evaluated as catalysts for CO oxidation. CeO2 nanorods showed superior activity to the others. When space velocity was 12,000 mL·gcat−1·h−1, the reaction temperature for 90% CO conversion (T90) was 228 °C. The main reason for the high activity was the existence of large amounts of easily reducible oxygen species, with a reduction temperature of 217 °C on the surface of CeO2 nanorods. Another cause was their relatively large surface area.

scholarly journals Rapid Microwave Synthesis of β-SnWO4 Nanoparticles: An Efficient Anode Material for Lithium-Ion Batteries

2020 ◽  
Author(s):  
Sumedha N ◽  
Mabkhoot Alsaiari ◽  
Mohammed Jalalah ◽  
Shashank M ◽  
Fahad Alharthi ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Structural Parameters ◽  
Lithium Ion ◽  
High Specific Capacitance ◽  
Stoichiometric Ratio ◽  
X Ray ◽  
Transmission Electron ◽  
Adsorption Desorption ◽  
Charge Discharge

Abstract Here, we report a facile synthesis of β-SnWO4 nanoparticles via microwave heat treatment using SnCl2 and H2WO4, in the presence of tamarind seed powder. X-ray diffraction analysis confirmed the crystalline nature, revealing a cubic structure of β-SnWO4 nanoparticles. Morphological features were visualized using a scanning electron microscope which exhibited homogenously distributed clusters of nanoparticles which were further confirmed using transmission electron microscope. The micrographs also displayed some porosity. Energy dispersive X-ray spectroscopy confirmed the elemental contents such as tin, oxygen and tungsten in the same stoichiometric ratio as expected by the respective empirical formula. High-resolution transmission electron microscope was used to find the d-spacing which was ultimately used to analyze the structural parameters. The spectrum obtained using Fourier transform infrared spectroscopy illuminates different stretching vibrations. Additionally, Barrett-Joyner-Halenda analysis was carried out to investigate N2 adsorption-desorption isotherm as well as to govern the pore size distribution. Cyclic voltammetry measurements were implemented to analyze the ongoing electrode reactions throughout the charge/discharge for β-SnWO4 nanostructures. The galvanometric charge/discharge curves for β-SnWO4 have also been discussed. A high specific capacitance (600 mAhg-1 at 0.1 C) and excellent columbic efficiency (~100%) was achieved.

Synthesis and Characterization of Dense Mesoporous Alumina

2014 ◽  
Vol 616 ◽  
pp. 252-257
Author(s):  
Atsushi Nakahira ◽  
Hironobu Nishimoto ◽  
Yukitaka Hamada ◽  
Yuki Yamasaki
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Surface Area ◽  
High Specific Surface Area ◽  
Mesoporous Alumina ◽  
Bet Surface Area ◽  
Synthesis And Characterization ◽  
Narrow Pore Size Distribution

Dense mesoporous alumina bulks were successfully synthesized by a hydrothermal hot-pressing (HHP) method for mesoporous alumina powders prepared as starting material with a high BET surface area and narrow pore size distribution. As a result, mesoporous alumina HHP bulks had high density with uniformity pore size distribution and a high specific surface area. Their microstructural features for dense mesoporous alumina bulks were observed by SEM. The characterization of mesopores was examined.

Incorporation of Pd Nanoparticles on Rod and Necklace-Like SBA-15 Supports Materials

2014 ◽  
Vol 917 ◽  
pp. 10-17
Author(s):  
Siew Pei Lee ◽  
Anita Ramli ◽  
Muralithran G. Kutty ◽  
Sharifah Bee A. Hamid
Keyword(s):  
Electron Microscope ◽  
Ion Exchange ◽  
Scanning Electron Microscope ◽  
Mass Spectrometer ◽  
Pd Nanoparticles ◽  
Transmission Electron ◽  
Icp Ms ◽  
Different Types ◽  
Adsorption Desorption ◽  
Scanning Electron

Ion-exchange of palladium (Pd) precursor for two different types of well-ordered SBA-15 morphologies, necklace-like and rod-like, was studied. Approximately 3.8 wt% Pd was successfully incorporated into SBA-15 at pH 10.3. Formation of SBA-15 and Pd/SBA-15 were characterized by Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Thermogravimetry with Simultaneous Difference Thermal Spectroscopy coupled with mass spectrometer (TG/SDTA-MS), Thermogravimetry in combination with Simultaneous Difference Thermal Spectroscopy (TG-SDTA), Inductive Coupled Plasma Mass Spectrometer (ICP-MS) and N2 adsorption-desorption. Reduction of surface area and pore volume of support for Pd/SBA-15 samples may indicate the encapsulation of PdO particles within mesoporous channels of SBA-15.

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