scholarly journals Magnetically Separable Chiral Periodic Mesoporous Organosilica Nanoparticles

2020 ◽  
Vol 10 (17) ◽  
pp. 5960
Author(s):  
Suheir Omar ◽  
Raed Abu-Reziq
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Periodic Mesoporous Organosilica ◽  
X Ray ◽  
Mesoporous Organosilica ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
First Time

We describe, for the first time, a successful strategy for synthesizing chiral periodic mesoporous organosilica nanoparticles (PMO NPs). The chiral PMO nanoparticles were synthesized in a sol–gel process under mild conditions; their preparation was mediated by hydrolysis and condensation of chiral-bridged organo-alkoxysilane precursor compounds, (OR‘)3Si-R-Si(OR‘)3, in the presence of cetyltrimethylammonium bromide (CTAB) surfactant. The resulting nanoparticles were composed merely from a chiral- bridged organo-alkoxysilane monomer. These systems were prepared by applying different surfactants and ligands that finally afforded monodispersed chiral PMO NPs consisting of 100% bridged-organosilane precursor. In addition, the major advancement that was achieved here was, for the first time, success in preparing magnetic chiral PMO NPs. These nanoparticles were synthesized by the co-polymerization of 1,1′-((1R,2R)-1,2-diphenylethane-1,2-diyl)bis(3-(3-(triethoxysilyl) propyl) urea) chiral monomer by an oil in water (o/w) emulsion process, to afford magnetic chiral PMO NPs with magnetite NPs in their cores. The obtained materials were characterized with high-resolution scanning electron microscopy (HR-SEM), high-resolution transmission electron microscopy (HR-TEM), energy-dispersive X-ray (EDX) spectroscopy, powder X-ray diffraction (XRD), solid-state NMR analysis, circular dichroism (CD) analysis, and nitrogen sorption analysis (N2-BET).

Preparation of TiO2/Ga2O3 Nanowires by a Sol-Gel-Solvothermal Method

2010 ◽  
Vol 663-665 ◽  
pp. 965-968
Author(s):  
Yue Hui Wang ◽  
Dong Jun Wang ◽  
Ai Jun Song ◽  
Zhi Gang Zhang ◽  
Shi Tao Song
Keyword(s):  
Electron Microscopy ◽  
Near Infrared ◽  
Solvothermal Method ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Tetrabutyl Titanate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
First Time

TiO2/Ga2O3 nanowires were successfully prepared by a sol–gel-solvothermal method using tetrabutyl titanate as precursor, alcohol as solvent, Ga2O3 as templet and dopants, alginate as dispersant. The structures, morphologies,compositions and catalytic activity of products have been characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy ( FESEM ), nitrogen adsorption test, ultraviolet-visible near-infrared spectroscopy (UV–vis–NIR ),energy dispersive X-ray (EDX) analysis and spectrophotometer. The results revealed that the as-synthesized TiO2/Ga2O3 nanowires grew along [001] direction,which is reported for the first time, and the as-prepared product had better optical activity than TiO2 nanoparticles. Finally, the nanowires have a good adsorption capacity of 128.2 m2/g tested through nitrogen adsorption.

Preparation of Alumina Powders through Pyrocatechol, Resorcinol Mediated Sol-Gel Method

2016 ◽  
Vol 850 ◽  
pp. 742-747
Author(s):  
Xiang Zhang ◽  
Ping Yun Li ◽  
Xiao De Guo ◽  
Ting Yan
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grain Sizes ◽  
Xrd Study ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Scanning Electron ◽  
Organic Monomer

Ultrafine alumina powders were synthesized through pyrocatechol and resorcinol mediated sol-gel process. Aluminum nitrate was applied as the Al source and PVP was the dispersant. X-ray diffraction (XRD) study displayed that γ-Al2O3 powders formed in the range of 800-900 °C, and then γ-Al2O3 transformed to α-Al2O3 at higher temperatures, pure α-Al2O3 powders could be obtained at 1000 °C by using resorcinol as organic monomer. The results of transmission electron microscopy (TEM) revealed that Al2O3 nanoparticles with γ crystalline phase had grain sizes in the range of 5-40 nm. Scanning electron microscopy (SEM) observation displayed that the morphology of the prepared α-Al2O3 powders had aggregated bodies formed by Al2O3 grains in the range of 0.2-0.5μm. These results provide a new way of preparation of alumina powders.

Synthesis of SnO2 by Sol-Gel Method

2016 ◽  
Vol 254 ◽  
pp. 200-206 ◽  
Author(s):  
Catalina Nuțescu Duduman ◽  
María Isabel Barrena Pérez ◽  
José Maria Gómez de Salazar ◽  
Ioan Carcea ◽  
Daniela Lucia Chicet ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Chemical Composition ◽  
Diffraction Pattern ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Transmission Electron ◽  
Sol Gel Process

Nanostructured SnO2 was prepared based on the sol-gel method used in the preparation of crystalline metal oxides. Sol-gel process can be described as a forming network of oxide polycondensation reaction of a molecular precursor in a liquid. Six experiments were carried out. Morphological structures and chemical composition were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) after calcination. It is noted that TEM images show that the spheres consist from nanocrystals, quantitative EDS analysis of the chemical composition shows an absence of the chlorine, which is a desired fact. For structural characterization of the material we used X-Ray Diffraction (XRD). The X-ray diffraction pattern for all samples indicates peaks which are agreeable with standard diffraction pattern of SnO2. The particle size of all samples was in the range of 28-92 nm calculated according to Scherrer equation.

scholarly journals Preparation and Characterization of Novel Mixed Periodic Mesoporous Organosilica Nanoparticles

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1569
Author(s):  
Hao Li ◽  
Laurence Raehm ◽  
Clarence Charnay ◽  
Jean-Olivier Durand ◽  
Roser Pleixats
Keyword(s):  
Cetyltrimethylammonium Bromide ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Periodic Mesoporous Organosilica ◽  
X Ray ◽  
Surface Areas ◽  
Mesoporous Organosilica ◽  
Transmission Electron ◽  
Cp Mas Nmr

We report herein the preparation of mixed periodic mesoporous organosilica nanoparticles (E-Pn 75/25 and 90/10 PMO NPs) by sol-gel co-condensation of E-1,2-bis(triethoxysilyl)ethylene ((E)-BTSE or E) with previously synthesized disilylated tert-butyl 3,5-dialkoxybenzoates bearing either sulfide (precursor P1) or carbamate (precursor P2) functionalities in the linker. The syntheses were performed with cetyltrimethylammonium bromide (CTAB) as template in the presence of sodium hydroxide in water at 80 °C. The nanomaterials have been characterized by Transmission Electron Microscopy (TEM), nitrogen-sorption measurements (BET), Dynamic Light Scattering (DLS), zeta-potential, Thermogravimetric Analysis (TGA), FTIR, 13C CP MAS NMR and small angle X-ray diffraction (p-XRD). All the nanomaterials were obtained as mesoporous rodlike-shape nanoparticles. Remarkably, E-Pn 90/10 PMO NPs presented high specific surface areas ranging from 700 to 970 m2g−1, comparable or even higher than pure E PMO nanorods. Moreover, XRD analyses showed an organized porosity for E-P1 90/10 PMO NPs typical for a hexagonal 2D symmetry. The other materials showed a worm-like mesoporosity.

scholarly journals Highly Active Ruthenium Catalyst Supported on Magnetically Separable Mesoporous Organosilica Nanoparticles

2020 ◽  
Vol 10 (17) ◽  
pp. 5769
Author(s):  
Suheir Omar ◽  
Raed Abu-Reziq
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Direct Method ◽  
Sol Gel ◽  
Reaction Medium ◽  
Ruthenium Oxide ◽  
Reduction Reaction ◽  
Periodic Mesoporous Organosilica ◽  
X Ray ◽  
Mesoporous Organosilica

A facile and direct method for synthesizing magnetic periodic mesoporous organosilica nanoparticles from pure organosilane precursors is described. Magnetic ethylene- and phenylene-bridged periodic mesoporous organosilica nanoparticles (PMO NPs) were prepared by nanoemulsification techniques. For fabricating magnetic ethylene- or phenylene-bridged PMO NPs, hydrophobic magnetic nanoparticles in an oil-in-water (o/w) emulsion were prepared, followed by a sol–gel condensation of the incorporated bridged organosilane precursor (1,2 bis(triethoxysilyl)ethane or 1,4 bis(triethoxysilyl)benzene), respectively. The resulting materials were characterized using high-resolution scanning electron microscopy (HR-SEM), high-resolution transmission electron microscopy (HR-TEM), energy-dispersive X-ray (EDX) spectroscopy, powder X-ray diffraction (XRD), solid-state NMR analysis, and nitrogen sorption analysis (N2-BET). The magnetic ethylene-bridged PMO NPs were successfully loaded using a ruthenium oxide catalyst by means of sonication and evaporation under mild conditions. The obtained catalytic system, termed Ru@M-Ethylene-PMO NPS, was applied in a reduction reaction of aromatic compounds. It exhibited very high catalytic behavior with easy separation from the reaction medium by applying an external magnetic field.

A High Resolution Study of G.P. Zones in Aluminum - 4.2 at % Silver

1982 ◽  
Vol 40 ◽  
pp. 722-723 ◽  
Author(s):  
R. Gronsky
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Computer Simulations ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Resolution Study

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.

scholarly journals Quartz Crystallite Size and Moganite Content as Indicators of the Mineralogical Maturity of the Carboniferous Chert: The Case of Cherts from Eastern Asturias (Spain)

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 611
Author(s):  
Celia Marcos ◽  
María de Uribe-Zorita ◽  
Pedro Álvarez-Lloret ◽  
Alaa Adawy ◽  
Patricia Fernández ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Crystallite Size ◽  
Archaeological Sites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Infrared And Raman Spectroscopy ◽  
First Time ◽  
Geological Formations

Chert samples from different coastal and inland outcrops in the Eastern Asturias (Spain) were mineralogically investigated for the first time for archaeological purposes. X-ray diffraction, X-ray fluorescence, transmission electron microscopy, infrared and Raman spectroscopy and total organic carbon techniques were used. The low content of moganite, since its detection by X-ray diffraction is practically imperceptible, and the crystallite size (over 1000 Å) of the quartz in these cherts would be indicative of its maturity and could potentially be used for dating chert-tools recovered from archaeological sites. Also, this information can constitute essential data to differentiate the cherts and compare them with those used in archaeological tools. However, neither composition nor crystallite size would allow distinguishing between coastal and inland chert outcrops belonging to the same geological formations.

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