The effect of arc parameters on the growth of carbon nanotubes

1997 ◽  
Vol 12 (6) ◽  
pp. 1536-1544 ◽  
Author(s):  
J. M. Lauerhaas ◽  
J. Y. Dai ◽  
A. A. Setlur ◽  
R. P. H. Chang
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Sources ◽  
Building Blocks ◽  
Carbon Ions ◽  
Transmission Electron ◽  
Microscopy Investigation ◽  
Electron Microscopy Investigation ◽  
Polycyclic Aromatic ◽  
Carbon Nanotube Growth ◽  
Nanotube Growth

The influence of starting carbon material on the generation of carbon nanotubes is investigated. Comparisons are made between oriented graphite, randomly oriented graphite, carbon black, and a polycyclic aromatic hydrocarbon as carbon sources in helium and hydrogen arcs. Transmission electron microscopy investigation of the redeposited rod formed on the cathode and the soot from the chamber walls provides evidence for the building blocks that lead to the nanostructures formed. It is postulated that polycyclic aromatic hydrocarbons are precursors for carbon nanotube growth in a hydrogen arc. While, in the case of helium, low molecular weight carbon ions and molecules have been previously hypothesized by others to be the building blocks for nanotube growth.

scholarly journals Understanding the local structure of disordered carbons from cellulose and lignin

2021 ◽  
Author(s):  
Yujie Meng ◽  
Cristian I. Contescu ◽  
Peizhi Liu ◽  
Siqun Wang ◽  
Seung-Hwan Lee ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Treatment Temperature ◽  
Graphite Sheet ◽  
Transmission Electron ◽  
Microscopy Investigation ◽  
Electron Microscopy Investigation ◽  
Scanning Transmission ◽  
Disordered Carbon ◽  
Biomass Components ◽  
Softwood Kraft Lignin

AbstractAn electron microscopy investigation was performed to understand the relationship between the microstructure and properties of carbonized cellulose and lignin (softwood kraft lignin) relative to the structure of the original biomass components. Structure details at micro- and molecular levels were investigated by scanning transmission electron microscopy. Atomic-resolution images revealed the presence of random disordered carbon in carbonized cellulose (C-CNC) and of large domains of well-ordered carbon with graphite sheet structure in carbonized lignin (C-Lignin). These structural differences explain why C-CNC exhibits higher surface area and porosity than C-Lignin. The presence of certain well-ordered carbon in carbonized lignin indicates some of the carbon in lignin are graphitized with heat treatment temperature up to 950 °C. This result is encouraging for future endeavors of attaining acceptable modulus of carbon fiber from lignin given suitable modifications to the chemistry and structure of lignin. The results of this research contribute to an improved understanding of the carbonization mechanism of the key cellulose and lignin components of biomass materials.

scholarly journals Free energy surface of initial cap formation in carbon nanotube growth

2021 ◽  
Author(s):  
Satoru Fukuhara ◽  
Yasushi Shibuta
Keyword(s):  
Carbon Nanotubes ◽  
Free Energy ◽  
Carbon Nanotube ◽  
Energy Surface ◽  
Catalyst Surface ◽  
Important Process ◽  
Free Energy Surface ◽  
Carbon Nanotube Growth ◽  
Nanotube Growth ◽  
Carbon Network

Initial cap formation is an important process of carbon nanotubes (CNTs) growth where hexagonal carbon network is lifted off from the catalyst surface. In this study, free energy surface (FES)...

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