Core–shell structures with metallic silver as nucleation agent of low expansion phases in BaO/SrO/ZnO/SiO2 glasses

CrystEngComm ◽  
2019 ◽  
Vol 21 (29) ◽  
pp. 4373-4386 ◽  
Author(s):  
Christian Thieme ◽  
Michael Kracker ◽  
Katrin Thieme ◽  
Christian Patzig ◽  
Thomas Höche ◽  
...  
Keyword(s):  
Scanning Transmission Electron Microscopy ◽  
Nucleating Agent ◽  
Shell Structures ◽  
Metallic Silver ◽  
X Ray Diffraction ◽  
Nucleation Agent ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission

The role of silver as a nucleating agent in BaO/SrO/ZnO/SiO2 glasses is studied with a range of microstructure-characterization techniques, such as scanning transmission electron microscopy, ultraviolet-visible spectroscopy, and X-ray diffraction.

scholarly journals MINERALOGICAL AND SPECTROSCOPIC STUDY OF NESQUEHONITE SYNTHESIZED BY REACTION OF GASEOUS CO2 WITH MG CHLORIDE SOLUTION

2017 ◽  
Vol 50 (4) ◽  
pp. 2009
Author(s):  
V. Skliros ◽  
A. Anagnostopoulou ◽  
P. Tsakiridis ◽  
M. Perraki
Keyword(s):  
Scanning Transmission Electron Microscopy ◽  
Chloride Solution ◽  
Raw Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
Raman Spectroscopic ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Permanent Storage ◽  
Ir And Raman

Nesquehonite, a hydrous carbonate with promising uses such as building raw material and treatment of wastewaters, was synthesized under low pressure conditions by reaction of gaseous CO2 with Mg chloride solution and it was studied by means of X-Ray Diffraction, optical and scanning/transmission electron microscopy, and FTIR and Raman spectroscopic methods. Synthesized nesquehonite forms elongated fibers, exhibiting transparent to translucent diaphaneity and vitreous luster. It is characterized by high crystallinity. IR and Raman spectroscopy indicated the presence of OHand HCO3 - in the crystal structure of nesquehonite. The nesquehonite synthesis described herein constitutes a potential permanent storage of CO2 emissions.

Enhancing the photocatalytic degradation of selected chlorophenols using Ag/zno nanocomposites

MRS Advances ◽  
2018 ◽  
Vol 3 (36) ◽  
pp. 2129-2136
Author(s):  
Kate Kotlhao ◽  
Fanyana M. Mtunzi ◽  
Vusumzi Pakade ◽  
Neelan Laloo ◽  
Ikechukwu P. Ejidike ◽  
...  
Keyword(s):  
Scanning Transmission Electron Microscopy ◽  
Silver Content ◽  
Zinc Nitrate ◽  
Nitrate Hexahydrate ◽  
X Ray Diffraction ◽  
Water Contaminants ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Xrd Patterns

Chlorophenols are among the priority listed water contaminants due to their estrogenic, mutagenic or carcinogenic health effects. The Ag/ZnO nanocomposites (NCs) were synthesized, characterized and tested for photacatalytic degradation of chlorophenols in water. The synthesis was done using zinc nitrate hexahydrate (ZnNO3. 6H2O) precursor and sodium hydroxide (NaOH). Silver nitrate (AgNO3) was added to ZnO and reduced with sodium brohydride to produce the silver nanoparticles (NPs) within the ZnO structure. The silver content was varied from 1, 3 and 5wt% for optimisation. The nanocomposites were characterised using ultraviolet - visible spectroscopy (UV-Vis), photolumniscence (PL), x-ray diffraction (XRD), and scanning transmission electron microscopy (STEM). The nanocomposites were tested for their photocatalytic properties on 2- chlorophenol (CP), 2- chlorophenol (CP) and 2,4- dichlorophenol (DCP) in water. The UV-Vis results showed that, as the amount of silver was increased a gradual slight red shift was observed. The XRD patterns for Ag/ZnO exhibited peaks that were characteristic of the hexagonal wurzite structure and peaks characteristic for Ag appeared at 38.24o, 44.37o, 64.67oand 77.58ocorresponding to (111), (200), (220) and (311) reflection planes. STEM results showed the presence of Ag in ZnO with ZnO appearing as rods shapes. The EDX elemental analysis confirmed the presence of Ag in the Ag/ZnO nanocomposites with no contaminants peaks. On testing the nanocomposites for phohotocatalytic degradation of chlorophenols, addition of Ag to ZnO improved degradation of the chlorophenols compared to the pristine ZnO.

Microstructure of Epitaxial SrTiO3/Pt/Ti/ Sapphire Heterostructures

2005 ◽  
Vol 20 (9) ◽  
pp. 2261-2265 ◽  
Author(s):  
Steffen Schmidt ◽  
Young-Woo Ok ◽  
Dmitri O. Klenov ◽  
Jiwei Lu ◽  
Sean P. Keane ◽  
...  
Keyword(s):  
Scanning Transmission Electron Microscopy ◽  
Film Plane ◽  
Growth Mechanisms ◽  
Radio Frequency Magnetron Sputtering ◽  
X Ray Diffraction ◽  
Orientation Relationships ◽  
Pt Electrode ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission

The microstructure and orientation relationships of epitaxial (111)-oriented SrTiO3 thin films grown by radio frequency magnetron sputtering on epitaxial (111)-oriented Pt/Ti electrodes on sapphire were investigated using x-ray diffraction, conventional and scanning transmission electron microscopy. We show that the epitaxial growth of (111)-oriented SrTiO3 films was promoted by thin Ti adhesion layers underneath the Pt electrode. The SrTiO3 films nucleated with two twin-related orientation variants, rotated by 180° about the 〈111〉 surface normal. The twin boundaries were oriented approximately normal to the film plane, but no strong preference for a specific boundary plane was observed. Growth mechanisms and the relationships to the dielectric properties are discussed.

scholarly journals Structure refinement of the δ1pphase in the Fe–Zn system by single-crystal X-ray diffraction combined with scanning transmission electron microscopy

2014 ◽  
Vol 70 (2) ◽  
pp. 275-282 ◽  
Author(s):  
Norihiko L. Okamoto ◽  
Katsushi Tanaka ◽  
Akira Yasuhara ◽  
Haruyuki Inui
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Single Crystal ◽  
Scanning Transmission Electron Microscopy ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission

The structure of the δ1pphase in the iron−zinc system has been refined by single-crystal synchrotron X-ray diffraction combined with scanning transmission electron microscopy. The large hexagonal unit cell of the δ1pphase with the space group ofP63/mmccomprises more or less regular (normal) Zn12icosahedra, disordered Zn12icosahedra, Zn16icosioctahedra and dangling Zn atoms that do not constitute any polyhedra. The unit cell contains 52 Fe and 504 Zn atoms so that the compound is expressed with the chemical formula of Fe13Zn126. All Fe atoms exclusively occupy the centre of normal and disordered icosahedra. Iron-centred normal icosahedra are linked to one another by face- and vertex-sharing forming two types of basal slabs, which are bridged with each other by face-sharing with icosioctahedra, whereas disordered icosahedra with positional disorder at their vertex sites are isolated from other polyhedra. The bonding features in the δ1pphase are discussed in comparison with those in the Γ and ζ phases in the iron−zinc system.

scholarly journals Synthesis and Characterisation of Nanocomposite Mo-Fe-B Thin Films Deposited by Magnetron Sputtering

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1739
Author(s):  
Paulius Malinovskis ◽  
Stefan Fritze ◽  
Justinas Palisaitis ◽  
Erik Lewin ◽  
Jörg Patscheider ◽  
...  
Keyword(s):  
Magnetron Sputtering ◽  
Scanning Transmission Electron Microscopy ◽  
X Ray Diffraction ◽  
Rich Phase ◽  
X Ray ◽  
Amorphous Phases ◽  
Transmission Electron ◽  
Fe Content ◽  
Direct Current Magnetron Sputtering ◽  
Scanning Transmission

Several ternary phases are known in the Mo-Fe-B system. Previous ab initio calculations have predicted that they should exhibit a tempting mix of mechanical and magnetic properties. In this study, we have deposited Mo-Fe-B films with a Fe-content varying from 0–37 at.% using non-reactive DC (direct current) magnetron sputtering. The phase composition, microstructure, and mechanical properties were investigated using X-ray diffraction, scanning transmission electron microscopy, and nanoindentation measurements. Films deposited at 300 °C and with >7 at.% Fe are nanocomposites consisting of two amorphous phases: a metal-rich phase and a metal-deficient phase. Hardness and elastic modulus were reduced with increasing Fe-content from ~29 to ~19 GPa and ~526 to ~353 GPa, respectively. These values result in H3/E2 ratios of 0.089–0.052 GPa, thereby indicating brittle behaviour of the films. Also, no indication of crystalline ternary phases was observed at temperatures up to 600 °C, suggesting that higher temperatures are required for such films to form.

scholarly journals Calcium Determines the Supramolecular Organization of Fibrillin-rich Microfibrils

1998 ◽  
Vol 141 (3) ◽  
pp. 829-837 ◽  
Author(s):  
T.J. Wess ◽  
P.P. Purslow ◽  
M.J. Sherratt ◽  
J. Ashworth ◽  
C.A. Shuttleworth ◽  
...  
Keyword(s):  
Scanning Transmission Electron Microscopy ◽  
Extracellular Matrices ◽  
Supramolecular Organization ◽  
Reversible Change ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Diffraction Peaks

Microfibrils are ubiquitous fibrillin-rich polymers that are thought to provide long-range elasticity to extracellular matrices, including the zonular filaments of mammalian eyes. X-ray diffraction of hydrated bovine zonular filaments demonstrated meridional diffraction peaks indexing on a fundamental axial periodicity (D) of ∼56 nm. A Ca2+-induced reversible change in the intensities of the meridional Bragg peaks indicated that supramolecular rearrangements occurred in response to altered concentrations of free Ca2+. In the presence of Ca2+, the dominant diffracting subspecies were microfibrils aligned in an axial 0.33-D stagger. The removal of Ca2+ caused an enhanced regularity in molecular spacing of individual microfibrils, and the contribution from microfibrils not involved in staggered arrays became more dominant. Scanning transmission electron microscopy of isolated microfibrils revealed that Ca2+ removal or addition caused significant, reversible changes in microfibril mass distribution and periodicity. These results were consistent with evidence from x-ray diffraction. Simulated meridional x-ray diffraction profiles and analyses of isolated Ca2+-containing, staggered microfibrillar arrays were used to interpret the effects of Ca2+. These observations highlight the importance of Ca2+ to microfibrils and microfibrillar arrays in vivo.

scholarly journals Structural Characterizations of Palladium Clusters Prepared by Polyol Reduction of [PdCl4]2−Ions

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Loredana Schiavo ◽  
Lucrezia Aversa ◽  
Roberta Tatti ◽  
Roberto Verucchi ◽  
Gianfranco Carotenuto
Keyword(s):  
Photoelectron Spectroscopy ◽  
Chemical Properties ◽  
Nucleating Agent ◽  
X Ray Diffraction ◽  
Palladium Clusters ◽  
X Ray ◽  
Transmission Electron ◽  
Hydrogen Technology ◽  
Physical And Chemical

Palladium nanoparticles are of great interest in many industrial fields, ranging from catalysis and hydrogen technology to microelectronics, thanks to their unique physical and chemical properties. In this work, palladium clusters have been prepared by reduction of [PdCl4]2−ions with ethylene glycol, in the presence of poly(N-vinyl-2-pyrrolidone) (PVP) as stabilizer. The stabilizer performs the important role of nucleating agent for the Pd atoms with a fast phase separation, since palladium atoms coordinated to the polymer side-groups are forced at short distances during nucleation. Quasispherical palladium clusters with a diameter of ca. 2.6 nm were obtained by reaction in air at 90°C for 2 hours. An extensive materials characterization by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and other characterizations (TGA, SEM, EDS-SEM, and UV-Vis) has been performed in order to evaluate the structure and oxidation state of nanopalladium.

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