scholarly journals Control the Morphologies and the Pore Architectures of Mesoporous Silicas through a Dual-Templating Approach

2012 ◽  
Vol 2012 ◽  
pp. 1-8
Author(s):  
Hairui Wang ◽  
Hao Chen ◽  
Zhen Xu ◽  
Sibing Wang ◽  
Baozong Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mesoporous Silica ◽  
Volume Ratio ◽  
Mesoporous Silicas ◽  
Low Molecular Weight ◽  
Silica Nanospheres ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Microscopy Techniques

Mesoporous silica nanospheres were prepared using a chiral cationic low-molecular-weight amphiphile and organic solvents such as toluene, cyclohexane, and tetrachlorocarbon through a dual-templating approach. X-ray diffraction, nitrogen sorption, field emission scanning electron microscopy, and transmission electron microscopy techniques have been used to characterize the mesoporous silicas. The volume ratio of toluene to water plays an important role in controlling the morphologies and the pore architectures of the mesoporous silicas. It was also found that mesoporous silica nanoflakes can be prepared by adding tetrahydrofuran to the reaction mixtures.

Mixed-Solvothermal Preparation of Mace-Like CdS Nanocrystals

2012 ◽  
Vol 502 ◽  
pp. 164-168
Author(s):  
Ling Xu ◽  
Han Mei Hu ◽  
Hai Yan Xu
Keyword(s):  
Electron Microscopy ◽  
Large Scale ◽  
Volume Ratio ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Transmission Electron ◽  
Cds Nanostructures ◽  
Uv Visible ◽  
Solvothermal Preparation

Novel mace-like (wolf-teeth clubs) CdS nanostructures were successfully prepared on a large scale using CdCl2•2.5H2O and NH2CSNH2 as starting materials through a convenient mixed-solvothermal route. The as-synthesized products were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectrometry (EDX), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and UV-visible absorption spectroscopy. The experimental results reveal that the morphology of CdS products was greatly affected by the volume ratio of anhydrous ethanol and distilled water. The possible mechanism for the formation of mace-like CdS nanostructures is simply discussed.

scholarly journals Preparation of Mesoporous Silica-Supported Palladium Catalysts for Biofuel Upgrade

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Ling Fei ◽  
Harvind Kumar Reddy ◽  
Joshua Hill ◽  
Qianglu Lin ◽  
Bin Yuan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mesoporous Silica ◽  
Palladium Catalysts ◽  
Methyl Esters ◽  
Catalyst Activity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Cnts Surface ◽  
Supported Palladium

We report the preparation of two hydrocracking catalysts Pd/CoMoO4/silica and Pd/CNTs/CoMoO4/silica (CNTs, carbon nanotubes). The structure, morphologies, composition, and thermal stability of catalysts were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, transmission electron microscopy (TEM), energy-dispersive X-ray (EDX), and thermogravimetric analysis (TGA). The catalyst activity was measured in a Parr reactor with camelina fatty acid methyl esters (FAMEs) as the feed. The analysis shows that the palladium nanoparticles have been incorporated onto mesoporous silica in Pd/CoMoO4/silica or on the CNTs surface in Pd/CNTs/CoMoO4/silica catalysts. The different combinations of metals and supports have selective control cracking on heavy hydrocarbons.

Formation of α-Fe2O3 Nanoflakes by Heating Fe in Air

2007 ◽  
Vol 121-123 ◽  
pp. 45-48 ◽  
Author(s):  
T. Yu ◽  
C.H. Sow ◽  
X.J. Xu ◽  
Y.W. Zhu ◽  
Chwee Teck Lim ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Volume Ratio ◽  
Electron Field Emission ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Glancing Angle ◽  
Electron Field ◽  
Method Show ◽  
Si Wafer

Flake-shaped hematite (α-Fe2O3) nanostructure has been successfully fabricated by using a hot-plate to directly heat Fe foil or Fe-coated substrates in air at 300oC. After heating, the surface of the samples was found to be populated with α-Fe2O3 nanoflakes. Such growth of α-Fe2O3 nanoflakes was very substrate-friendly. They can be formed on blank Si wafer, patterened Si, AFM tips, silica sphere, quartz, glass slide, Al foil and electrochemically etched W tip. The formation process and the final products were investigated by glancing angle x-ray diffraction (GAXRD), micro-Raman, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicate the final products are single crystalline α-Fe2O3 nanoflakes vertically standing on the Fe3O4 film that acts as the precursor for growth of α-Fe2O3. The α-Fe2O3 nanoflakes formed by this method show very sharp tip with the tip radii as small as several nanometers and large surface to volume ratio. Such nanoflakes may be potentially useful as novel candidates for future electron field emission and gas senor devices. Furthermore, it is believed that this simple and substrates-friendly method is useful in extending the applications of α-Fe2O3 nanostructures.

scholarly journals Misfit phase (BiSe)1.10NbSe2 as the origin of superconductivity in niobium-doped bismuth selenide

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Machteld E. Kamminga ◽  
Maria Batuk ◽  
Joke Hadermann ◽  
Simon J. Clarke
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Impurity Phase ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Niobium Doped ◽  
Microscopy Techniques ◽  
Superconducting Behaviour

Abstract Topological superconductivity is of great contemporary interest and has been proposed in doped Bi2Se3, in which electron-donating atoms such as Cu, Sr or Nb have been intercalated into the Bi2Se3 structure. For NbxBi2Se3, with Tc ~ 3 K, it is assumed in the literature that Nb is inserted in the van der Waals gap. However, in this work an alternative origin for the superconductivity in Nb-doped Bi2Se3 is established. In contrast to previous reports, it is deduced that Nb intercalation in Bi2Se3 does not take place. Instead, the superconducting behaviour in samples of nominal composition NbxBi2Se3 results from the (BiSe)1.10NbSe2 misfit phase that is present in the sample as an impurity phase for small x (0.01 ≤ x ≤ 0.10) and as a main phase for large x (x = 0.50). The structure of this misfit phase is studied in detail using a combination of X-ray diffraction and transmission electron microscopy techniques.

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.

Identification of calcium oxalate crystals in dried or fixed tobacco leaf

1984 ◽  
Vol 42 ◽  
pp. 288-289
Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Oxalate ◽  
Growth And Development ◽  
Polarized Light ◽  
Calcium Oxalate Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

The Effect of the Microstructure of Diffusion Barriers on the Palladium Activation for Electroless Copper Deposition

2002 ◽  
Vol 716 ◽  
Author(s):  
Seok Woo Hong ◽  
Yong Sun Lee ◽  
Ki-Chul Park ◽  
Jong-Wan Park
Keyword(s):  
Electron Microscopy ◽  
Diffusion Barriers ◽  
Copper Deposition ◽  
X Ray Diffraction ◽  
Plan View ◽  
X Ray ◽  
Transmission Electron ◽  
Electroless Copper ◽  
Sheet Resistance Measurement ◽  
Scanning Electron

AbstractThe effect of microstructure of dc magnetron sputtered TiN and TaN diffusion barriers on the palladium activation for autocatalytic electroless copper deposition has been investigated by using X-ray diffraction, sheet resistance measurement, field emission scanning electron microscopy (FE-SEM) and plan view transmission electron microscopy (TEM). The density of palladium nuclei on TaN diffusion barrier increases as the grain size of TaN films decreases, which was caused by increasing nitrogen content in TaN films. Plan view TEM results of TiN and TaN diffusiton barriers showed that palladium nuclei formed mainly on the grain boundaries of the diffusion barriers.

Palladium Nanowire Thin Films via Template Growth

2003 ◽  
Vol 775 ◽  
Author(s):  
Donghai Wang ◽  
David T. Johnson ◽  
Byron F. McCaughey ◽  
J. Eric Hampsey ◽  
Jibao He ◽  
...  
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Thin Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Conductive Substrate ◽  
Palladium Nanowires ◽  
Efficient Route ◽  
Silica Thin Film

AbstractPalladium nanowires have been electrodeposited into mesoporous silica thin film templates. Palladium continually grows and fills silica mesopores starting from a bottom conductive substrate, providing a ready and efficient route to fabricate a macroscopic palladium nanowire thin films for potentially use in fuel cells, electrodes, sensors, and other applications. X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicate it is possible to create different nanowire morphology such as bundles and swirling mesostructure based on the template pore structure.

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