Journal ArticleDOI
Atomic-scale imaging of carbon nanofibre growth
Stig Helveg,Carlos López-Cartes,Carlos López-Cartes,Jens Sehested,Poul L. Hansen,Clausen Bjerne Steffen,Jens R. Rostrup-Nielsen,Frank Abild-Pedersen,Jens K. Nørskov +8 more
TLDR
Time-resolved, high-resolution in situ transmission electron microscope observations of the formation of carbon nanofibres from methane decomposition over supported nickel nanocrystals show that metallic step edges act as spatiotemporal dynamic growth sites and may be important for understanding other types of catalytic reactions and nanomaterial syntheses.Abstract:
The synthesis of carbon nanotubes with predefined structure and functionality plays a central role in the field of nanotechnology1,2, whereas the inhibition of carbon growth is needed to prevent a breakdown of industrial catalysts for hydrogen and synthesis gas production3. The growth of carbon nanotubes and nanofibres has therefore been widely studied4,5,6,7,8,9,10. Recent advances in in situ techniques now open up the possibility of studying gas–solid interactions at the atomic level11,12. Here we present time-resolved, high-resolution in situ transmission electron microscope observations of the formation of carbon nanofibres from methane decomposition over supported nickel nanocrystals. Carbon nanofibres are observed to develop through a reaction-induced reshaping of the nickel nanocrystals. Specifically, the nucleation and growth of graphene layers are found to be assisted by a dynamic formation and restructuring of mono-atomic step edges at the nickel surface. Density-functional theory calculations indicate that the observations are consistent with a growth mechanism involving surface diffusion of carbon and nickel atoms. The finding that metallic step edges act as spatiotemporal dynamic growth sites may be important for understanding other types of catalytic reactions and nanomaterial syntheses.read more
Citations
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Water-Assisted Highly Efficient Synthesis of Impurity-Free Single-Walled Carbon Nanotubes
TL;DR: In this article, the authors demonstrate the efficient chemical vapor deposition synthesis of single-walled carbon nanotubes where the activity and lifetime of the catalysts are enhanced by water.
Journal Article
Water-Assisted Highly Efficient Synthesis of Impurity-Free Single-Walled Carbon Nanotubes-``Super-Growth''
TL;DR: Water-stimulated enhanced catalytic activity results in massive growth of superdense and vertically aligned nanotube forests with heights up to 2.5 millimeters that can be easily separated from the catalysts, providing nanotubes material with carbon purity above 99.98%.
Journal ArticleDOI
Carbon nanotubes and nanofibers in catalysis
TL;DR: In this article, the use of carbon nanotubes (CNT) and nanofibers as catalysts and catalysts supports has been analyzed from the early 1990s until the beginning of 2003.
Journal ArticleDOI
A review of chemical vapour deposition of graphene on copper
TL;DR: In this paper, the authors provide a detailed and up-to-date description of the literature on the subject as well as highlighting challenges that must be overcome for the utilization of graphene deposited on copper substrates by chemical vapour deposition.
Journal ArticleDOI
Nanocarbons for the Development of Advanced Catalysts
TL;DR: This poster presents a probabilistic procedure to evaluate the response of the H2O/O2 mixture to various pyrolysis conditions and shows promising results in both the horizontal and the vertical domain.
References
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Georg Kresse,Jürgen Furthmüller +1 more
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Journal ArticleDOI
Carbon Nanotubes--the Route Toward Applications
TL;DR: Many potential applications have been proposed for carbon nanotubes, including conductive and high-strength composites; energy storage and energy conversion devices; sensors; field emission displays and radiation sources; hydrogen storage media; and nanometer-sized semiconductor devices, probes, and interconnects.
Journal ArticleDOI
Improved adsorption energetics within density-functional theory using revised Perdew-Burke-Ernzerhof functionals
TL;DR: In this paper, a simple formulation of a generalized gradient approximation for the exchange and correlation energy of electrons has been proposed by Perdew, Burke, and Ernzerhof (PBE), which improves the chemisorption energy of atoms and molecules on transition-metal surfaces.
Journal ArticleDOI
Crystalline Ropes of Metallic Carbon Nanotubes
Andreas Thess,R. S. Lee,Pavel Nikolaev,Hongjie Dai,Pierre Petit,J. Robert,Chunhui Xu,Young Hee Lee,Seong-Gon Kim,Andrew G. Rinzler,Daniel T. Colbert,Gustavo E. Scuseria,David Tománek,John E. Fischer,Richard E. Smalley +14 more
TL;DR: X-ray diffraction and electron microscopy showed that fullerene single-wall nanotubes (SWNTs) are nearly uniform in diameter and that they self-organize into “ropes,” which consist of 100 to 500 SWNTs in a two-dimensional triangular lattice with a lattice constant of 17 angstroms.