scholarly journals Zeolite-Assisted Shear Exfoliation of Graphite into Few-Layer Graphene

Crystals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 377 ◽  
Author(s):  
Gabriela Tubon Usca ◽  
Cristian Vacacela Gomez ◽  
Marco Guevara ◽  
Talia Tene ◽  
Jorge Hernandez ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Low Cost ◽  
Great Promise ◽  
Layer Graphene ◽  
Morphological Studies ◽  
Transmission Electron ◽  
Potential Applications ◽  
Novel Method ◽  
Inorganic Layered Materials ◽  
Few Layer Graphene

A novel method is presented to prepare few-layer graphene (FLG) in N-methyl-2-pyrrolidinone (NMP) by using a simple, low-cost and energy-effective shear exfoliation assisted by zeolite and using a cappuccino mixer to produce shear. We propose that the exfoliation of natural graphite flakes can be achieved using inelastic collisions between graphite flakes and zeolite particles in a dynamic colloidal fluid. To confirm the exfoliation of FLG, spectroscopy and morphological studies are carried out using Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Additionally, the obtained graphene shows a linear flow of current and low resistance. The proposed method shows great promise for the industrial-scale synthesis of high-quality graphene with potential applications in future graphene-based devices, and furthermore, this method can be extended to exfoliate inorganic layered materials such as BN and MoS2.

Few-Layer Graphene as a Support Film for Transmission Electron Microscopy Imaging of Nanoparticles

2009 ◽  
Vol 1 (12) ◽  
pp. 2886-2892 ◽  
Author(s):  
James R. McBride ◽  
Andrew R. Lupini ◽  
Michael A. Schreuder ◽  
Nathanael J. Smith ◽  
Stephen J. Pennycook ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Microscopy Imaging ◽  
Layer Graphene ◽  
Transmission Electron ◽  
Few Layer Graphene

scholarly journals Structure of Coal-Derived Metal-Supported Few-Layer Graphene Composite Materials Synthesized Using a Microwave-Assisted Catalytic Graphitization Process

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1672
Author(s):  
Faridul Islam ◽  
Arash Tahmasebi ◽  
Rou Wang ◽  
Jianglong Yu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Bituminous Coal ◽  
Critical Role ◽  
Fabricated Metal ◽  
Catalytic Graphitization ◽  
Microwave Assisted ◽  
Layer Graphene ◽  
Transmission Electron ◽  
Few Layer Graphene

Metal-supported few-layer graphene (FLG) was synthesized via microwave-assisted catalytic graphitization owing to the increasing demand for it and its wide applications. In this study, we quickly converted earth-abundant and low-cost bituminous coal to FLG over Fe catalysts at a temperature of 1300 °C. X-ray diffraction, Raman spectroscopy, transmission electron microscopy, and N2 adsorption–desorption experiments were performed to analyze the fabricated metal-supported FLG. The results indicated that the microwave-irradiation temperature at a set holding-time played a critical role in the synthesis of metal-supported FLG. The highest degree of graphitization and a well-developed pore structure were fabricated at 1300 °C using a S10% Fe catalyst for 20 min. High-resolution transmission electron microscopy analysis confirmed that the metal-supported FLG fabricated via microwave-assisted catalytic graphitization consisted of 3–6 layers of graphene nanosheets. In addition, the 2D band at 2700 cm−1 in the Raman spectrum of the fabricated metal-supported FLG samples were observed, which indicated the presence of few-layer graphene structure. Furthermore, a mechanism was proposed for the microwave-assisted catalytic graphitization of bituminous coal. Here, we developed a cost-effective and environmental friendly metal-supported FLG method using a coal-based carbonaceous material.

scholarly journals Inhibition of vacuum sublimation artefacts for (Scanning) Transmission Electron Microscopy ((S)TEM) of sulphur samples via encapsulation

2022 ◽  
Vol 2 ◽  
pp. 1
Author(s):  
Oskar Ronan ◽  
Clive Downing ◽  
Valeria Nicolosi
Keyword(s):  
Electron Microscopy ◽  
Low Cost ◽  
Storage Device ◽  
Structure Property ◽  
Vacuum Sublimation ◽  
Capacity Loss ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Novel Method ◽  
Sulfur Battery

Lithium-sulfur battery is one of promising candidates for next-generation energy storage device due to the sulfur cathode material with low cost and nontoxicity, and super high theoretical energy density (nearly 2600Wh kg−1) and specific energy (2567Wh kg−1). Sulphur, however, poses a few interesting challenges before it can gain widespread utilisation. The biggest issue is known as the polysulphide shuttling effect which contributes to rapid capacity loss after cycling. Accurate characterisation of sulphur cathodic materials becomes critical to our understanding polysulphide shuttling effect in the quest of finding mitigating solutions. Electron microscopy is playing a crucial role in battery research in determining structure–property–function relations. However, sulphur undergoes sublimation at a point above the typical pressures found in the column of a transmission electron microscope (TEM) at room temperature. This makes the imaging and characterisation of any sort of nanostructured sulphur samples challenging, as the material will be modified or even disappear rapidly as soon as it is inserted into the TEM vacuum. As a result, materials characterised by such methods are prone to deviation from normal conditions to a great extent. To prevent this, a novel method of encapsulating sulphur particles between silicon nitride (SiNx) membranes is demonstrated in this work.

Transmission Electron Microscopy of oriented Co84Cr14Ta2 thin films for longitudinal magnetic recording

1991 ◽  
Vol 49 ◽  
pp. 756-757
Author(s):  
T. P. Nolan
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Low Cost ◽  
Low Noise ◽  
Information Storage ◽  
High Coercivity ◽  
Magnetic Alloy ◽  
Magnetic Media ◽  
Transmission Electron

Thin film magnetic media are being used as low cost, high density forms of information storage. The development of this technology requires the study, at the sub-micron level, of morphological, crystallographic, and magnetic properties, throughout the depth of the deposited films. As the microstructure becomes increasingly fine, widi grain sizes approaching 100Å, the unique characterization capabilities of transmission electron microscopy (TEM) have become indispensable to the analysis of such thin film magnetic media.Films were deposited at 225°C, on two NiP plated Al substrates, one polished, and one circumferentially textured with a mean roughness of 55Å. Three layers, a 750Å chromium underlayer, a 600Å layer of magnetic alloy of composition Co84Cr14Ta2, and a 300Å amorphous carbon overcoat were then sputter deposited using a dc magnetron system at a power of 1kW, in a chamber evacuated below 10-6 torr and filled to 12μm Ar pressure. The textured medium is presently used in industry owing to its high coercivity, Hc, and relatively low noise. One important feature is that the coercivity in the circumferential read/write direction is significandy higher than that in the radial direction.

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