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Title: Catalytical growth of carbon nanotubes/fibers from nanocatalysts prepared by laser pulverization of nickel sulfate

Abstract

Dispersed nickel sulfate (NiSO{sub 4}) microclusters on Si substrates were fragmented by pulsed excimer laser irradiation to serve as catalysts for carbon nanotube/nanofiber (CNT/CNF) growth. At proper fluences, NiSO{sub 4} clusters were pulverized into nanoparticles. The sizes of clusters/nanoparticles were found to be dependent on laser fluence and laser pulse number. By increasing the laser fluence from 100 to 300 mJ/cm{sup 2}, the size of disintegrated particles decreased drastically from several micrometers to several nanometers. It was found that laser-induced disintegration of as-dispersed NiSO{sub 4} clusters was mainly due to physical fragmentation by transient thermal expansion/contraction. Thermal melting of nanoparticles in a multipulse regime was also suggested. Hot-filament chemical vapor deposition (HFCVD) was used for growth of CNTs from the pulsed-laser treated catalysts. For samples irradiated at 100 and 200 mJ/cm{sup 2}, CNFs were dominant products. These CNFs grew radially out of big NiSO{sub 4} clusters, forming dendritic CNF bunches. For samples irradiated at 300 mJ/cm{sup 2}, dense multiwalled carbon nanotubes (MWCNFs) with uniform diameters were obtained. It is suggested that elemental Ni was formed through thermal decomposition of NiSO{sub 4} clusters/nanoparticles during HFCVD. The size and the shape of the Ni aggregation, which were determined by the initial sizemore » of NiSO{sub 4} clusters/nanoparticles, might affect the preference in the synthesis of CNTs or CNFs.« less

Authors:
; ; ;  [1];  [2]
  1. Department of Electrical Engineering, University of Nebraska--Lincoln, Lincoln, Nebraska 68588-0511 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
20787802
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 99; Journal Issue: 2; Other Information: DOI: 10.1063/1.2165403; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CARBON; CARBON FIBERS; CATALYSIS; CHEMICAL VAPOR DEPOSITION; CRYSTAL GROWTH; EXCIMER LASERS; FRAGMENTATION; IRRADIATION; LASER MATERIALS; MELTING; NANOTUBES; NICKEL SULFATES; PARTICLES; PYROLYSIS; SUBSTRATES; SYNTHESIS; THERMAL EXPANSION

Citation Formats

Shi, J., Lu, Y.F., Tan, K.F., Wang, X.W., and Department of Mechanical Engineering, University of Nebraska--Lincoln, Lincoln, Nebraska 68588-0656. Catalytical growth of carbon nanotubes/fibers from nanocatalysts prepared by laser pulverization of nickel sulfate. United States: N. p., 2006. Web. doi:10.1063/1.2165403.
Shi, J., Lu, Y.F., Tan, K.F., Wang, X.W., & Department of Mechanical Engineering, University of Nebraska--Lincoln, Lincoln, Nebraska 68588-0656. Catalytical growth of carbon nanotubes/fibers from nanocatalysts prepared by laser pulverization of nickel sulfate. United States. doi:10.1063/1.2165403.
Shi, J., Lu, Y.F., Tan, K.F., Wang, X.W., and Department of Mechanical Engineering, University of Nebraska--Lincoln, Lincoln, Nebraska 68588-0656. Sun . "Catalytical growth of carbon nanotubes/fibers from nanocatalysts prepared by laser pulverization of nickel sulfate". United States. doi:10.1063/1.2165403.
@article{osti_20787802,
title = {Catalytical growth of carbon nanotubes/fibers from nanocatalysts prepared by laser pulverization of nickel sulfate},
author = {Shi, J. and Lu, Y.F. and Tan, K.F. and Wang, X.W. and Department of Mechanical Engineering, University of Nebraska--Lincoln, Lincoln, Nebraska 68588-0656},
abstractNote = {Dispersed nickel sulfate (NiSO{sub 4}) microclusters on Si substrates were fragmented by pulsed excimer laser irradiation to serve as catalysts for carbon nanotube/nanofiber (CNT/CNF) growth. At proper fluences, NiSO{sub 4} clusters were pulverized into nanoparticles. The sizes of clusters/nanoparticles were found to be dependent on laser fluence and laser pulse number. By increasing the laser fluence from 100 to 300 mJ/cm{sup 2}, the size of disintegrated particles decreased drastically from several micrometers to several nanometers. It was found that laser-induced disintegration of as-dispersed NiSO{sub 4} clusters was mainly due to physical fragmentation by transient thermal expansion/contraction. Thermal melting of nanoparticles in a multipulse regime was also suggested. Hot-filament chemical vapor deposition (HFCVD) was used for growth of CNTs from the pulsed-laser treated catalysts. For samples irradiated at 100 and 200 mJ/cm{sup 2}, CNFs were dominant products. These CNFs grew radially out of big NiSO{sub 4} clusters, forming dendritic CNF bunches. For samples irradiated at 300 mJ/cm{sup 2}, dense multiwalled carbon nanotubes (MWCNFs) with uniform diameters were obtained. It is suggested that elemental Ni was formed through thermal decomposition of NiSO{sub 4} clusters/nanoparticles during HFCVD. The size and the shape of the Ni aggregation, which were determined by the initial size of NiSO{sub 4} clusters/nanoparticles, might affect the preference in the synthesis of CNTs or CNFs.},
doi = {10.1063/1.2165403},
journal = {Journal of Applied Physics},
number = 2,
volume = 99,
place = {United States},
year = {Sun Jan 15 00:00:00 EST 2006},
month = {Sun Jan 15 00:00:00 EST 2006}
}
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