Formation of bismuth iron oxide based core–shell structures and their dielectric, ferroelectric and magnetic properties

2019 ◽  
Vol 7 (5) ◽  
pp. 1280-1291 ◽  
Author(s):  
Alaka Panda ◽  
R. Govindaraj ◽  
R. Mythili ◽  
G. Amarendra
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Magnetic Properties ◽  
Iron Oxide ◽  
Shell Structures ◽  
Core Shell ◽  
Bismuth Iron Oxide ◽  
The Core ◽  
Shell Nanostructures ◽  
Transmission Electron

Bismuth and iron oxides subjected to ball milling followed by controlled annealing treatments showed the formation of core–shell nanostructures with Bi2Fe4O9 as the core and a shell of BiFeO3 and Bi25FeO40 phases as deduced based on the analysis of transmission electron microscopy results.

Preparation of Carbon-Encapsulated Fe Core-Shell Nanostructures by Confined Arc Plasma

2011 ◽  
Vol 688 ◽  
pp. 245-249 ◽  
Author(s):  
Zhi Qiang Wei ◽  
Xiao Yun Wang ◽  
Hua Yang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Specific Surface ◽  
Surface Area ◽  
Core Shell ◽  
Arc Plasma ◽  
X Ray ◽  
The Core ◽  
Transmission Electron

Special carbon encapsulated Fe core-shell nanoparticles with a size range of 15–40 nm were successfully prepared via confined arc plasma method. The composition, morphology, microstructure, specific surface area, particle size of the product by this process were characterized via X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), X-ray energy dispersive spectrometry (XEDS) and BET N2adsorption. The experiment results shown that the carbon encapsulated Fe nanoparticles with clear core-shell structure, the core of the particles is body centered cubic (BCC) structure Fe, and the shell of the particles is disorder carbons. The particle size of the nanocapsules ranges from 15 to 40nm，with an averaged value about 30nm, the particles diameter of the core is about 16nm and the thickness of the shells is about 6-8 nm, and the specific surface area is 24 m2/g.

Structural Characterization of Nanoparticles Obtained by a Polyol Synthesis in the Bimetallic System Pt-Pd

2012 ◽  
Vol 1372 ◽  
Author(s):  
A. F. García-Ruiz ◽  
J. J. Velázquez Salazar ◽  
R. Esparza ◽  
N. Castillo
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Bimetallic Nanoparticles ◽  
Synthesis Method ◽  
Shell Structures ◽  
Polyol Synthesis ◽  
Core Shell ◽  
Thermal Methods ◽  
Transmission Electron ◽  
Bimetallic System

ABSTRACTA modified polyol synthesis has been utilized to study the different structures obtained in the bimetallic system of platinum (Pt) and palladium (Pd). Some results are shown in this work. Thermal methods under refluxing, carrying on the reaction up to 285 ºC, have been assayed to reduce metallic salts using ethylene glycol (EG) as reducer and polyvinylpyrrolidone (PVP) as protective reagent of the formed bimetallic nanoparticles. The special core-shell structure has been observed in these bimetallic nanoparticles, whose synthesis was assisted by Ag, showing polyhedral shapes. The average diameter size of the core has been estimated at 10 nm, and the diameter size of the shell in 13 nm, consequently the thickness of the shell is around 1.5 nm. Nanoparticles were structurally characterized with transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM) equipped with detector to generate high angle annular dark field (HAADF) images. This kind of structures have been studied and utilized to increase successfully the catalytic properties of monometallic nanoparticles of Pt or Pd according to other works. Here, the synthesis procedure is described; as the main results, several images are presented showing the obtained bimetallic core-shell structures and their fast Fourier transform (FFT), and also the size and the elemental analysis of the nanoparticles are reported, concluding that this synthesis method is very efficient for preparing bimetallic core shell structures.

Formation of superlattices in blends of 3-miktoarm star terpolymers with diblock copolymers

e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
Volker Abetz ◽  
Shimei Jiang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Diblock Copolymers ◽  
Shell Structures ◽  
Core Shell ◽  
Transmission Electron ◽  
Miktoarm Star ◽  
Triblock Terpolymers ◽  
Cyclohexyl Methacrylate

Abstract In this contribution we report on the morphological structures formed in blends of microphase-separated 3-miktoarm star terpolymers of polystyrene-armpolybutadiene- arm-poly(2-vinylpyridine) (SBV*) and polystyrene-block-polybutadiene (SB), polystyrene-block-poly(2-vinylpyridine) (SV), poly(2-vinylpyridine)- block-poly(cyclohexyl methacrylate) (VC) diblock copolymers. The morphologies are characterized by transmission electron microscopy. Blends with similar morphologies as known from linear triblock terpolymers are found, like core-shell structures based on cylinders or gyroids. Other blends show very distorted morphologies, or morphologies similar to the ones found for pure 3-miktoarm star terpolymers. While attractive interactions between blocks of the two species enhance the formation of common superlattices, blends with too large diblock copolymers tend to macrophase-separate.

Morphological characterization of the core-shell latex particle by transmission electron microscopy and image analysis

2003 ◽  
Vol 89 (3) ◽  
pp. 855-861 ◽  
Author(s):  
Zhengmin Li ◽  
Jinghe Yang ◽  
Yuanzhang Yu ◽  
Xingzhong Xu ◽  
Xiantan Meng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Image Analysis ◽  
Latex Particle ◽  
Morphological Characterization ◽  
Core Shell ◽  
The Core ◽  
Transmission Electron

scholarly journals Synthesis, Characterization and Dye Removal Behavior of Core–Shell–Shell Fe3O4/Ag/Polyoxometalates Ternary Nanocomposites

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1255 ◽  
Author(s):  
Shixia Zhan ◽  
Chunyan Li ◽  
Heyun Tian ◽  
Chenguang Ma ◽  
Hongling Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Magnetic Properties ◽  
Removal Efficiency ◽  
Dye Removal ◽  
Physical Property Measurement System ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Transmission Electron ◽  
Vis Spectroscopy

The ternary nanocomposites Fe3O4/Ag/polyoxometalates (Fe3O4/Ag/POMs) with core–shell–core nanostructure were synthesized by coating [Cu(C6H6N2O)2(H2O)]H2[Cu(C6H6N2O)2(P2Mo5O23)]·4H2O polyoxometalates on the surface of Fe3O4/Ag (core–shell) nanoparticles. The transmission electron microscopy/high resolution transmission electron microscopy (HR-TEM) and X-ray powder diffraction (XRD) analyses show that the Fe3O4/Ag/POMs ternary nanocomposites reveal a core–shell–core nanostructure, good dispersibility, and high crystallinity. The vibrating sample magnetometer (VSM) and physical property measurement system (PPMS) demonstrated the good magnetic properties and superparamagnetic behavior of the nanocomposites at 300 K. The UV–vis spectroscopy displayed the broadband absorption of the Fe3O4/Ag/POMs with the maximum surface plasmon resonance of Ag nanostructure around 420 nm. The dye removal capacity of Fe3O4/Ag/POMs was investigated using methylene blue (MB) as a probe. Through adsorption and photocatalysis, the nanocomposites could quickly remove MB with a removal efficiency of 98.7% under the irradiation of visible light at room temperature. The removal efficiency was still as high as 97.5% even after six runs by magnetic separation of photocatalytic adsorbents after processing, indicating the reusability and high stability of the nanocomposites. These Fe3O4/Ag/POMs photocatalytic adsorbents with magnetic properties will hopefully become a functional material for wastewater treatment in the future.

Transmission Electron Microscopy Study of Gold-Coated Iron Core-Shell and Au/Fe/Au Onion-Like Nanoparticles Synthesized using Reverse Micelles

1999 ◽  
Vol 581 ◽  
Author(s):  
W.L. Zhou ◽  
E.E. Carpenter ◽  
J. Sims ◽  
A. Kumbhar ◽  
C.J. O'Connor
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Shell Structure ◽  
Reverse Micelles ◽  
Iron Core ◽  
Core Shell ◽  
Gold Shell ◽  
The Core ◽  
Transmission Electron ◽  
Core Shell Structure

ABSTRACTGold-coated iron core-shell structure and Au/Fe/Au onion-like nanoparticles synthesized using reverse micelles were characterized by transmission electron microscopy (TEM). The average nanoparticle size of the core-shell structure is about 8 nm, with about 6 nm diameter core and 2 nm shell. The gold shell structure can be resolved from both high resolution electron microscopy (HREM) image and energy dispersive X-ray spectrum (EDS). Even though the gold and iron electron diffraction rings overlap a little bit, they can still be identified due to the slight mismatch of the diffraction rings. The Au/Fe/Au onion-like nanoparticles were also observed. The nanoparticles were formed with about 6 nm diameter gold core, 1 nm iron interlayer and 2 nm gold shell. The shell structure coated on the core appeared unhomogeneous, however, in both cases the iron core and interlayer iron shell stay air-stable.

scholarly journals Stability of a Bifunctional Cu-Based Core@Zeolite Shell Catalyst for Dimethyl Ether Synthesis Under Redox Conditions Studied by Environmental Transmission Electron Microscopy andIn SituX-Ray Ptychography

2017 ◽  
Vol 23 (3) ◽  
pp. 501-512 ◽  
Author(s):  
Sina Baier ◽  
Christian D. Damsgaard ◽  
Michael Klumpp ◽  
Juliane Reinhardt ◽  
Thomas Sheppard ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Dimethyl Ether ◽  
Core Shell ◽  
X Ray ◽  
Environmental Transmission ◽  
The Core ◽  
Transmission Electron ◽  
The Stability

AbstractWhen using bifunctional core@shell catalysts, the stability of both the shell and core–shell interface is crucial for catalytic applications. In the present study, we elucidate the stability of a CuO/ZnO/Al2O3@ZSM-5 core@shell material, used for one-stage synthesis of dimethyl ether from synthesis gas. The catalyst stability was studied in a hierarchical manner by complementary environmental transmission electron microscopy (ETEM), scanning electron microscopy (SEM) andin situhard X-ray ptychography with a specially designedin situcell. Both reductive activation and reoxidation were applied. The core–shell interface was found to be stable during reducing and oxidizing treatment at 250°C as observed by ETEM andin situX-ray ptychography, although strong changes occurred in the core on a 10 nm scale due to the reduction of copper oxide to metallic copper particles. At 350°C,in situX-ray ptychography indicated the occurrence of structural changes also on theµm scale, i.e. the core material and parts of the shell undergo restructuring. Nevertheless, the crucial core–shell interface required for full bifunctionality appeared to remain stable. This study demonstrates the potential of these correlativein situmicroscopy techniques for hierarchically designed catalysts.

Characterisation of 3D-GaN/InGaN core-shell nanostructures by transmission electron microscopy

2014 ◽  
Vol 11 (3-4) ◽  
pp. 425-427 ◽  
Author(s):  
Ian Griffiths ◽  
David Cherns ◽  
Xue Wang ◽  
Hergo-Heinrich Wehman ◽  
Martin Mandl ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Core Shell ◽  
Shell Nanostructures ◽  
Transmission Electron

Preparation of GDC Nanopowders and GDC/YSZ Core-Shell Nanocomposites

2010 ◽  
Vol 434-435 ◽  
pp. 717-718
Author(s):  
Zuo Cai Huang ◽  
Bin Li ◽  
Wei Liu ◽  
Wei Pan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Sol Gel ◽  
Precipitation Method ◽  
Core Shell ◽  
The Core ◽  
Transmission Electron ◽  
Core Shell Structure ◽  
Co Precipitation

Nanocrystalline GDC as small as 5 nm was successfully synthesized via the co-precipitation method. GDC/YSZ core-shell nanocrystals, which were GDC nanocrystals overcoated by a thin YSZ layer, was successfully synthesized by the addition of GDC nanocrystals in the YSZ source solution using sol-gel method. The core-shell structure was supported by its high-resolution transmission electron microscopy results and the composition was investigated by EDX method.

Multiple Morphologies of Gold–Magnetite Heterostructure Nanoparticles are Effectively Functionalized with Protein for Cell Targeting

2013 ◽  
Vol 19 (4) ◽  
pp. 821-834 ◽  
Author(s):  
Evan S. Krystofiak ◽  
Eric C. Mattson ◽  
Paul M. Voyles ◽  
Carol J. Hirschmugl ◽  
Ralph M. Albrecht ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Iron Oxide ◽  
Shell Structure ◽  
Cell Labeling ◽  
Core Shell ◽  
Metal Shell ◽  
Aqueous Synthesis ◽  
Transmission Electron ◽  
Core Shell Structure

AbstractNanoparticles composed of a magnetic iron oxide core surrounded by a metal shell have utility in a broad range of biomedical applications. However, the presence of surface energy differences between the two components makes wetting of oxide with metal unfavorable, precluding a “core–shell” structure of an oxide core completely surrounded by a thin metal shell. Three-dimensional island growth followed by island coalescence into thick shells is favored over the two-dimensional layer-by-layer growth of a thin, continuous metal coating of a true core–shell. Aqueous synthesis of gold-coated magnetite nanoparticles with analysis by infrared, energy-dispersive X-ray, and electron energy loss spectroscopies; high-resolution transmission electron microscopy; selected area electron diffraction; and high-angle annular dark-field scanning transmission electron microscopy showed two distinct morphologies that are inconsistent with an idealized core–shell. The majority were isolated ~16–22-nm-diameter nanoparticles consisting of ~7-nm-diameter magnetite and a thick deposition of gold, most often discontinuous, with some potentially “sandwiched” morphologies. A minority were aggregates of agglomerated magnetite decorated with gold but displaying significant bare magnetite. Both populations were successfully conjugated to fibrinogen and targeted to surface-activated platelets, demonstrating that iron oxide–gold nanoparticles produced by aqueous synthesis do not require an ideal core–shell structure for biological activity in cell labeling and targeting applications.

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