scholarly journals Finger-Like Carbon-Based Nanostructures Produced by Combustion of Flour-Based Sticks (Spaghetti)

2019 ◽  
Vol 5 (2) ◽  
pp. 21 ◽  
Author(s):  
Frederik Ossler ◽  
Crispin J. D. Hetherington
Keyword(s):  
Electron Microscopy ◽  
Carbon Film ◽  
Tube Formation ◽  
X Ray ◽  
The Core ◽  
Carbon Structures ◽  
Transmission Electron ◽  
Core Components ◽  
Biomass Materials ◽  
Graphene Structures

Biomass is becoming particularly important as a starting material for advanced carbon structures. In this study, we found interesting nanostructures on the surface of burnt spaghetti using scanning electron microscopy, transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX) for analysis. The structures were elongated and finger-like, with evidence that the tubes have shell and core components. The shell was carbon that included amorphous and layered graphene structures. EDX showed enriched potassium and phosphorous in the core and at the tip of the tubes. The results indicate that tube formation depends on phase separation of polar/ionic and nonpolar moieties when water is produced in the biomass from the pyrolysis/combustion. The tube growth is most probably due to the raising pressure of vapor that cannot escape through the carbon film that is formed at the surface of the stick from flame heat. This process resembles glass blowing or volcanic activity, where the carbon acts as the glass or earth’s crust, respectively. These observations suggest that new interesting tubular nanostructures with different properties on the inside and outside can be produced in a relatively simple way, utilizing processes of combustion of starch-rich biomass materials.

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.

Synthesis of the rod-like NiS2@C for hydrogen evolution reaction in acidic solution

2020 ◽  
Vol 13 (02) ◽  
pp. 2050009
Author(s):  
Xiujuan Wu ◽  
Jie Wang ◽  
Fan Zhang ◽  
Junyan Gong ◽  
Pinghao Xu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Evolution ◽  
Photoelectron Spectroscopy ◽  
Acidic Solution ◽  
Carbon Film ◽  
Chemical Deposition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Onset Potential ◽  
Transmission Electron

The carbon-based NiS2 nanorods (NiS2@C) were prepared by chemical deposition and sulfidation with nickel dimethylglyoximate (Ni(DMG)2) as the starting agent. The nanorods were analyzed by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy for chemical analysis. Structural characterization revealed that NiS2 existed on the surface of the rod and in the internal channels of the rod. In 0.5[Formula: see text]m H2SO4 solution, NiS2@C has lower onset potential and higher current density than NiS2. The results suggest that C improves the electrical conductivity of the NiS2 electrocatalyst, and the carbon film-based rod-like NiS2 is a more effective nanocomposite of hydrogen evolution.

Synthesis and Optical Properties of CdSe and CdSe/ZnS Core/Shell Quantum Dots

2015 ◽  
Vol 1085 ◽  
pp. 176-181
Author(s):  
Puspendu Barik ◽  
Arup Ratan Mandal ◽  
Denis V. Kuznetsov ◽  
Anna Yu. Godymchuk
Keyword(s):  
Electron Microscopy ◽  
Quantum Dots ◽  
Excitation Wavelength ◽  
Core Shell ◽  
Shell Material ◽  
X Ray Diffraction ◽  
Chemical Route ◽  
X Ray ◽  
The Core ◽  
Transmission Electron

In this work, we have synthesized homogeneous, ordered CdSe and CdSe/ZnS core/shell quantum dots (QDs) by chemical route and characterized them using X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), and Photoluminescence (PL) spectroscopy. Coating with shell material was confirmed by red shift as well as enhancement in the PL peak compared to bare QDs. DLS data showed QDs and core/shell to be stable. PL spectra are red shifted relative to the excitation wavelength. Bare QDs and the core/shell material shows a Stoke-shift of 16 and 18 meV respectively.

Large Scale Synthesis of BaTiO3 Nanorods by a Template Way

2009 ◽  
Vol 79-82 ◽  
pp. 373-376 ◽  
Author(s):  
Zhao Deng ◽  
Ying Dai ◽  
Hai Rui Liu ◽  
Wen Chen
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Large Scale ◽  
Template Method ◽  
Precipitation Process ◽  
X Ray ◽  
The Core ◽  
Transmission Electron ◽  
Scanning Electron

Large scale BaTiO3 nanorods were successfully synthesized by a template method based on a precipitation process. The templates used in our method are H2Ti8O17 nanorods, which can be synthesized from K2Ti4O9 fibers. The unique process of the synthesis is BaC2O4•0.5H2O shell was coated on the 1-dimensional H2Ti8O17 nanorods (the core). The as-prepared products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that the BaTiO3 nanorods are ~100-300 nm in diameter and ~2-10 m in length. The process described provides a general route to fabricate this kind of perovskite 1-dimensional nanostructures, such as SrTiO3 and PbTiO3.

Novel Method for Controlling Nano Thin Coatings on Particulate Materials

1998 ◽  
Vol 526 ◽  
Author(s):  
J. Fitz-Gerald ◽  
S. Pennycook ◽  
H. Gao ◽  
V. Krishnamoorthy ◽  
J. Marcinka ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Laser Ablation ◽  
New Technologies ◽  
Nano Particles ◽  
X Ray ◽  
The Core ◽  
Transmission Electron ◽  
Particulate Coatings ◽  
Core Particles

AbstractParticulate coatings have wide ranging applications in several new technologies such as flat-panel displays, sintering of advanced ceramics, rechargeable batteries, etc. In this paper, we show the feasibility of the pulsed laser ablation technique to make very thin, uniformly distributed and discrete coatings in particulate systems so that the properties of the core particles can be suitably modified. Presently, laser ablation techniques have been primarily applied to deposit thin films on flat substrate materials. To deposit discontinuous particulate coatings, the laser induced plume from the target comes in contact with an agitated bed of core particles. The pressure and nature of the background gas (inert or active) controls the cluster size of the nano particles in the laser plume. Experiments were conducted for laser deposition of Ag nano particles on Al2O3 and SiO2 core particles by pulsed excimer laser (wavelength = 248 nm and pulse duration = 25 nanosecond) irradiation of a Ag sputtering target The surface coverage and coating uniformities of the film were found to depend on the synthesis parameters (energy density, # laser pulses, gas pressure backfill gas, molecular weight) as well as the residence time of the core particles in the plume regime. The films were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), wavelength dispersive x-ray analysis (WDX), scanning transmission electron microscopy (STEM), and x-ray photoelectron spectroscopy (XPS).

RAPET (Reaction under Autogenic Pressure at Elevated Temperatures) Technique Assisted Synthesis of Encapsulated CdE@C [E= S, Se and Te] Nanocrystallites

2016 ◽  
Vol 16 (03) ◽  
pp. 1650032
Author(s):  
P. P. George ◽  
I. Genish ◽  
Shirly ben-david Maklouf ◽  
Y. Koltypin ◽  
A. Gedanken
Keyword(s):  
Electron Microscopy ◽  
Elevated Temperatures ◽  
Carbon Matrix ◽  
Average Diameter ◽  
Core Shell ◽  
Synthetic Method ◽  
X Ray ◽  
Cds Nanocrystals ◽  
The Core ◽  
Transmission Electron

We present an easy synthetic method for the fabrication of encapsulated nanosized semiconductor CdE [E [Formula: see text] S, Se and Te] within the core of carbon capsule. We also discuss the growth of CdSC and neat CdS nanocrystals on stainless steel coupons (SSC) by a reaction under autogenic pressure at elevated temperature (RAPET) technique. The thermal decomposition of mixture of Cd(acetate)2 and sulfur, selenium and tellurium was carried out at 750[Formula: see text]C under air for 3[Formula: see text]h. The synthesized products were systematically characterized by X-ray powder diffraction, scanning electron microscopy (SEM) and transmission electron microscopy. Carbon matrix, with an average diameter of 250[Formula: see text]nm, encapsulated several nanometric-sized CdS nanocrystals, as evidenced from high resolution SEM (HRSEM). We examined the optical properties of this core/shell CdS@C and nonencapsulated CdS nanocrystals and found that both core shell and neat CdS nanocrystals show emission in the pohotoluminescence (PL) spectrum.

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.

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

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.

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