Carbon nanotube nucleation driven by catalyst morphology dynamics.
Summary of "Carbon nanotube nucleation driven by catalyst morphology dynamics."
In situ observation of the carbon nanotube nucleation process accompanied by dynamic reconstruction of the catalyst particle morphology is considered within a thermodynamic approach. It reveals the driving force for the detachment of the sp(2)-carbon cap, so-called lift-off-a crucial event in nanotube growth. A continuum model and detailed atomistic calculations identify the critical factors in the lift-off process: (i) catalyst surface energy, affected by the chemisorbed carbon atoms at the exterior surface of the catalyst, exposed to the carbon feedstock; and (ii) the emergence of a pristine, high-energy facet under the sp(2)-carbon dome. This further allows one to evaluate the range of carbon feedstock chemical potential, where the lift-off process occurs, to be followed by emergence of single-walled nanotube, and provides insights into observed catalyst morphology oscillations leading to formation of multiwalled carbon nanotubes.
Affiliation
Honda Research Institute USA Inc. , Columbus, Ohio 43212, United States.
Journal Details
This article was published in the following journal.
Name: ACS nano
ISSN: 1936-086X
Pages: 10096-101
Links
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/22082229
- DOI: http://dx.doi.org/10.1021/nn2040457
Medical and Biotech [MESH] Definitions
Estrenes
Unsaturated derivatives of the ESTRANES with methyl groups at carbon-13, with no carbon at carbon-10, and with no more than one carbon at carbon-17. They must contain one or more double bonds.
Carbon-carbon Ligases
Enzymes that catalyze the joining of two molecules by the formation of a carbon-carbon bond. These are the carboxylating enzymes and are mostly biotinyl-proteins. EC 6.4.
Carbon-carbon Lyases
Enzymes that catalyze the cleavage of a carbon-carbon bond by means other than hydrolysis or oxidation. This subclass contains the DECARBOXYLASES, the ALDEHYDE-LYASES, and the OXO-ACID-LYASES. EC 4.1.
Carbon Isotopes
Stable carbon atoms that have the same atomic number as the element carbon, but differ in atomic weight. C-13 is a stable carbon isotope.
Carbon-carbon Double Bond Isomerases
Enzymes that catalyze the shifting of a carbon-carbon double bond from one position to another within the same molecule. EC 5.3.3.
PubMed Articles
Dynamic Catalyst Restructuring during Carbon Nanotube Growth.
We study the restructuring of solid nickel catalyst nanoparticles during carbon nanotube growth by environmental transmission electron microscopy and multiscale modeling. Our molecular dynamics/contin...
Tailoring the density of random single-walled carbon nanotube (SWCNT) networks is of paramount importance for various applications, yet it remains a major challenge due to the insufficient catalyst ac...
QM/MD Simulation of SWNT Nucleation on Transition-Metal Carbide Nanoparticles.
The mechanism and kinetics of single-walled carbon nanotube (SWNT) nucleation from Fe- and Ni-carbide nanoparticle precursors have been investigated using quantum chemical molecular dynamics (QM/MD) m...
Orientation and Morphological Evolution of Catalyst Nanoparticles During Carbon Nanotube Growth.
We examined the structure, morphology, and orientation of catalyst nanoparticles used for seeding and growing multiwall carbon nanotubes (MWCNTs) by plasma enhanced chemical vapor deposition in CH(4)/...
We report a numerical investigation on the catalytic growth mechanism of a single-walled carbon nanotube (SWNT) inside a template SWNT, that is, formation of a double-walled carbon nanotube (DWNT). Th...
Clinical Trials
Safety and Tolerability Study of Inhaled Carbon Monoxide in Kidney Transplant Patients
The purpose of this study is to evaluate the safety and tolerability of two carbon monoxide doses when administered as an inhaled gas for 1 hour in patients receiving kidney transplants.
The Cyclocapnic Method for Measurement of Chemosensitivity
We aim to test our method for measuring chemosensitivity (the ventilatory response to a change in carbon dioxide), which uses sinusoidal carbon dioxide stimuli. Hypotheses: - Ca...
Carbon Dioxide Insufflation on Cerebral Microemboli
The purpose of this study is to determine if blowing carbon dioxide into the surgical field during open-heart surgery to displace retained chest cavity air from the atmosphere will decreas...
Endovascular repair of infrarenal abdominal aortic aneurysms (AAA) requires a contrast agent to identify the vascular anatomy and placement of the stent graft. Iodine contrast has traditi...
Hyperbaric Oxygen Therapy for Acute Domestic Carbon Monoxide (CO) Poisoning
Carbon monoxide poisoning still places a burden on the healthcare system worldwide. While oxygen therapy is the cornerstone treatment, the role and practical modalities of hyperbaric oxyge...
