scholarly journals Formation of toroidal Li2O2 in non-aqueous Li–O2 batteries with Mo2CTx MXene/CNT composite

RSC Advances ◽  
2019 ◽  
Vol 9 (70) ◽  
pp. 41120-41125 ◽  
Author(s):  
Mihye Wu ◽  
Do Youb Kim ◽  
Hyunsoo Park ◽  
Kyeong Min Cho ◽  
Ju Ye Kim ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Growth Model ◽  
Surface Coverage ◽  
Cathode Surface ◽  
High Surface ◽  
Solution Growth

Mo2CTx supported on carbon nanotube was first applied as a cathode for Li–O2 batteries. The high surface coverage of Mo2CTx resulted in the toroidal Li2O2 formation via solution growth model due to the inaccessibility of O2 to the cathode surface.

scholarly journals Tailoring of Aqueous-Based Carbon Nanotube–Nanocellulose Films as Self-Standing Flexible Anodes for Lithium-Ion Storage

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 655 ◽  
Author(s):  
Hoang Kha Nguyen ◽  
Jaehan Bae ◽  
Jaehyun Hur ◽  
Sang Joon Park ◽  
Min Sang Park ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
High Surface ◽  
High Surface Area ◽  
Composite Films ◽  
Rate Capability ◽  
Morphological Characteristics ◽  
Lithium Ion ◽  
Reversible Capacity ◽  
High Rate ◽  
Voltage Profile

An easy and environmentally friendly method was developed for the preparation of a stabilized carbon nanotube–crystalline nanocellulose (CNT–CNC) dispersion and for its deposition to generate self-standing CNT–CNC composite films. The composite films were carbonized at different temperatures of 70 °C, 800 °C, and 1300 °C. Structural and morphological characteristics of the CNT–CNC films were investigated by X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM), which revealed that the sample annealed at 800 °C (CNT–CNC800) formed nano-tree networks of CNTs with a high surface area (1180 m2·g−1) and generated a conductive CNC matrix due to the effective carbonization. The carbonized composite films were applied as anodes for lithium-ion batteries, and the battery performance was evaluated in terms of initial voltage profile, cyclic voltammetry, capacity, cycling stability, and current rate efficiency. Among them, the CNT–CNC800 anode exhibited impressive electrochemical performance by showing a reversible capacity of 443 mAh·g−1 at a current density of 232 mA·g−1 after 120 cycles with the capacity retention of 89% and high rate capability.

Carbon nanotube dendrites: availability and their growth model

2001 ◽  
Vol 36 (13-14) ◽  
pp. 2519-2523 ◽  
Author(s):  
Anyuan Cao ◽  
Xianfeng Zhang ◽  
Cailu Xu ◽  
Ji Liang ◽  
Dehai Wu ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Growth Model

scholarly journals Theoretical Study of a 0.22 THz Backward Wave Oscillator Based on a Dual-Gridded, Carbon-Nanotube Cold Cathode

2018 ◽  
Vol 8 (12) ◽  
pp. 2462 ◽  
Author(s):  
Qingyun Chen ◽  
Xuesong Yuan ◽  
Matthew Cole ◽  
Yu Zhang ◽  
Lin Meng ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Output Power ◽  
Current Density ◽  
Compression Ratio ◽  
Cathode Surface ◽  
Electron Gun ◽  
Cold Cathode ◽  
Backward Wave Oscillator ◽  
Wave Oscillator ◽  
Backward Wave

The carbon nanotube (CNT) cold cathode is an attractive choice for millimeter and terahertz vacuum electronic devices owning to its unique instant switch-on and high emission current density. A novel, dual-gridded, field emission architecture based on a CNT cold cathode is proposed here. CNTs are synthesized directly on the cathode surface. The first separating grid is attached to the CNT cathode surface to shape the CNT cathode array. The second separating grid is responsible for controlled extraction of electrons from the CNT emitters. The cathode surface electric field distribution has been improved drastically compared to conventional planar devices. Furthermore, a high-compression-ratio, dual-gridded, CNT-based electron gun has been designed to further increase the current density, and a 21 kV/50 mA electron beam has been obtained with beam transparency of nearly 100%, along with a compression ratio of 39. A 0.22 THz disk-loaded waveguide backward wave oscillator (BWO) based on this electron gun architecture has been realized theoretically with output power of 32 W. The results indicate that higher output power and higher frequency terahertz BWOs can be made using advanced, nanomaterial-based cold cathodes.

scholarly journals PYRENE EMISSION FROM MONOLAYERS "CLICKED" ONTO QUARTZ

2013 ◽  
Vol 01 (01) ◽  
pp. 1250007
Author(s):  
HONGYAN SONG ◽  
SERGEY GORELIK ◽  
JONATHAN HOBLEY ◽  
JIEXUN LI ◽  
AÏCHA BOUDHAR ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Surface Coverage ◽  
Charge Transfer Band ◽  
Photophysical Properties ◽  
High Surface ◽  
Excimer Emission ◽  
Excitation Spectra ◽  
Visible Absorption ◽  
Molecular Monolayers ◽  
A Charge

A series of quartz surfaces were modified with a series of crosslinkers and functional groups in order to obtain an azide-terminated monolayer, which was then used to immobilize pyrene onto the surface via alkyne-azide "click" chemistry. During the course of the immobilization, different ratios of tert-butyl diphenyl chlorosilane were used to control the distribution and hence the photophysical properties of the pyrene on the surface. The preparative surface reactions and photophysical properties were investigated with contact angle, X-ray photoelectron spectroscopy, UV-visible absorption and emission spectroscopy. High surface coverage was achieved of just under 1molecule per nm2. At this coverage all emission from the pyrene was in the form of excimer emission. Excimer emission dominated at all surface coverages greater than 0.45 molecules per nm2. Below this coverage the monomer emission could also be observed. The conclusions that can be drawn are important for understanding the interactions of neighboring molecules in molecular monolayers. Our results suggest that at high surface coverage a substantial number of the pyrene molecules are already close enough to their neighbors that pairs of them can be directly excited to form excimer with no requirement for diffusion. This can be stated because the long wavelength end of the pyrene absorption and excitation spectra show a broad tail that is assigned to a charge transfer band resulting from an electron being directly transferred from a ground state pyrene to a neighboring pyrene molecule. Furthermore, absorption spectra shifts also indicate that the pyrene molecules undergo some interactions on the surface when they are closely packed.

scholarly journals High surface coverage of a self-assembled monolayer by in situ synthesis of palladium nanodeposits

Nanoscale ◽  
2017 ◽  
Vol 9 (35) ◽  
pp. 13281-13290 ◽  
Author(s):  
Lucía Herrer ◽  
Victor Sebastian ◽  
Santiago Martín ◽  
Alejandro González-Orive ◽  
Francesc Pérez-Murano ◽  
...  
Keyword(s):  
Surface Coverage ◽  
High Surface ◽  
In Situ Synthesis ◽  
Self Assembled Monolayer ◽  
Confined Growth ◽  
Growth Method ◽  
Self Assembled

Nascent metal|monolayer|metal devices have been fabricated by depositing palladium, by growing palladium nanodeposits through a CO-confined growth method.

Chemically Grafted Carbon Nanotube Surface Coverage Gradients

Langmuir ◽  
2010 ◽  
Vol 26 (23) ◽  
pp. 18468-18475 ◽  
Author(s):  
Cameron J. Shearer ◽  
Amanda V. Ellis ◽  
Joseph G. Shapter ◽  
Nicolas H. Voelcker
Keyword(s):  
Carbon Nanotube ◽  
Surface Coverage

scholarly journals First-principles-informed energetic span and microkinetic analysis of ethanol catalytic conversion to 1,3-butadiene on MgO

2020 ◽  
Author(s):  
Astrid Boje ◽  
William E. Taifan ◽  
Henrik Ström ◽  
Tomas Bucko ◽  
Jonas Baltrusaitis ◽  
...  
Keyword(s):  
Free Energy ◽  
Gas Phase ◽  
First Principles ◽  
Surface Coverage ◽  
Energy Landscape ◽  
High Surface ◽  
Catalytic Conversion ◽  
Free Energy Landscape ◽  
Catalyst Composition ◽  
The Impact

Kinetic modeling of single-step catalytic conversion of ethanol to 1,3-butadiene is necessary to inform accurate process design. This paper considers the synthesis of 1,3-butadiene on an MgO (100) step-edge using first-principles-informed energetic span and microkinetic analysis to explore the reaction free energy landscapes and kinetic limitations of competing reaction pathways. Previous studies have observed mechanisms proceeding via both dehydrogenation and dehydration of ethanol, and highlighted sensitivity to conditions and catalyst composition. Here, we use the energetic span concept to characterize the theoretical maximum turnover and degree of rate control for states in each reaction pathway, finding dehydrogenation to be more active than dehydration for producing 1,3-butadiene, and suggesting states in the dehydrogenation, dehydration, and condensation steps to be rate-determining. The influence of temperature on the relative rate contribution of each state is quantified and explained through the varying temperature sensitivity of the free energy landscape. A microkinetic model is developed to explore the impact of competition between pathways, interaction with gas-phase species, and high surface coverage of stable reaction intermediates. This suggests that the turnover obtained may be significantly lower than predicted from the free energy landscape alone. The theoretical rate-determining states were found to contribute to high surface coverage of adsorbed ethanol and longer, oxygenated hydrocarbons. The combined energetic span and microkinetic analysis permits investigation of a complex system from two perspectives, each with inherent advantages, and helps elucidate conflicting observations of rate determining steps and product distribution by considering the interplay between the different pathways and the equilibrium with gas-phase products.

scholarly journals Review on Carbon Nanotube Varieties for Healthcare Application: Effect of Preparation Methods and Mechanism Insight

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1654
Author(s):  
Jothi Ramalingam Rajabathar ◽  
Govindasami Periyasami ◽  
Amer M. Alanazi ◽  
Mani Govindasamy ◽  
Prabhakarn Arunachalam
Keyword(s):  
Antimicrobial Activity ◽  
Carbon Nanotube ◽  
High Surface ◽  
High Surface Area ◽  
Healthcare Sector ◽  
Contributing Factors ◽  
Bacterial Killing ◽  
Nanoparticle Deposition ◽  
Diverse Range ◽  
Carbon Based

Many potential uses of carbon nanotubes (CNT) in various sectors have created an urge to assess their diverse range of properties pertaining to various applications like catalysis, biosensor, and antimicrobial activity. Increasing studies on the biosensor and antibacterial activity of CNT have prompted tremendous interest in the utilization of the carbon-based nanostructured material as an alternative to currently existing antibiotics. However, the study of bactericidal aspects of this nanomaterial is relatively new and hence the deeper understanding of the various physicochemical characteristics and antimicrobial nature of CNT is extremely wanted. This review covers the effect of framework substitution and explains the understanding of membrane disintegration and oxidative stresses upon nanomaterials for antimicrobial activity. The present article has also reviewed effect of preparation nanoparticle deposition and framework modification on carbon nanotube structure. The recent research on graphene-modified nanomaterials for biosensor applications related to healthcare/clinical applications have also been discussed. Major physicochemical contributing factors such as size, functionalization, high surface area, and aggregation features of CNT assisting in the bacterial killing have nicely been outlined. Hence, the present review explains the supporting information related with Single and multi-walled carbon nanotube and summarized the advantages of functionalized carbon nanotube/graphene-based nanostructured carbon-based materials towards protection and reduction of bacterial/viral infections in the healthcare sector.

Two-Dimensional Fractal Structures of Metal Oxides Synthesized at Room Temperature

2008 ◽  
Vol 47-50 ◽  
pp. 1177-1180 ◽  
Author(s):  
Lan Chen ◽  
Ju Xu ◽  
Michael A. Morris
Keyword(s):  
Gas Sensors ◽  
Room Temperature ◽  
Surface Coverage ◽  
High Surface ◽  
Two Dimensional ◽  
Colloidal Solutions ◽  
Fractal Structures ◽  
Potential Applications ◽  
Very High ◽  
Catalyst Carriers

2D metal oxide fractal structures with different appearance and composition are successfully grown on the silicon (100) substrates from their colloidal solutions at room temperature. These films display very high surface coverage on the substrates and abundant structures. The results demonstrate the appearances and dimensions of these structures are dependent on the properties and composition of their constituent particles and the substrates. This work may have potential applications in the fabrication of gas sensors, photon-receivers and catalyst carriers which are not easy made by other methods at RT.

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