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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
201

The influence of physicochemical reaction parameters on the synthesis of multi-walled carbon nanotubes for use as catalyst supports.

Oosthuizen, Rachel Suzanne. January 2012 (has links)
Multi-walled carbon nanotubes (MWCNTs) and other shaped carbon nanomaterials (SCNMs) were synthesized by the floating catalyst chemical vapour deposition (CVD) method, using either ferrocene [1] as the catalyst at 2.5 or 5 wt.%, or a synthesized heteroatom-containing ferrocene derivative, in toluene, in the range 750 to 950 °C. The derivatives used were ferrocenoyl imidazolide [3] (a source of N and O) at 2.5 and 5 wt.%, (N-phenylcarbamoyl)ferrocene [4] (a source of N and O) at 1.25 wt.% and S,S-bis(ferrocenylmethyl)dithiocarbonate [5] (a source of S and O) at 2.5 wt.%, which was synthesized from ferrocenylmethanol [2]. These were characterized by melting point, 1H- and 13C-NMR spectroscopy, IR spectroscopy and mass spectrometry (MS). The effects of variations in the CVD physicochemical reaction parameters, namely temperature, catalyst employed (and the effect of its heteroatoms, where applicable) and catalyst concentration, on the CVD products were investigated. These materials were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive Xray spectroscopy (EDX), Raman spectroscopy, thermogravimetric analysis (TGA) and some by the Brunauer, Emmett and Teller method (BET). The best temperature range, in terms of high yields of MWCNTs with relatively high thermal stabilities and surface areas, in general, was identified as being 800 to 900 °C, from results obtained with [1]. This temperature range was used for further experiments. Among other results, it was shown that [1] and [3], at 2.5 wt.%, and at 800 and 850 °C respectively, produced the best materials. Catalysts [4] and [5] produced primarily carbon spheres, however, in general, all experiments using N-containing catalysts produced bamboo-shaped MWCNTs. For [3], at 2.5 wt.%, smaller bamboo compartment lengths correlated with decreasing temperature and decreasing crystallinity, suggesting a larger incorporation of nitrogen with lowered temperature. Catalyst [3] at 2.5 wt.% also produced very “clean” MWCNTs and this was attributed to optimal levels of oxygen being able to convert amorphous carbons to gas. Certain MWCNT properties were shown to be dependent on the combined, or synergistic, effects of catalyst concentration and temperature. The best undoped MWCNTs that were synthesized and commercially produced MWCNTs were loaded with Pd nanoparticles using a metal organic CVD (MOCVD) method. Results revealed well dispersed metal nanoparticles of narrow size distribution. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2012.
202

Synthesis and characterization of carbon nanotube supported nanoparticles for catalysis

Vijayaraghavan, Ganesh, January 1900 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.
203

Study of factors affecting the synthesis of carbon nanotubes by spray pyrolysis

Xiao, Jiajia, January 2007 (has links)
Thesis (M.S.)--University of Texas at El Paso, 2007. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.
204

Molecular dynamics simulation of heat transport across silicon-carbon nanotubes interface

Kim, Taejin, January 2007 (has links) (PDF)
Thesis (Ph. D.)--Washington State University, December 2007. / Includes bibliographical references (p. 124-129).
205

Carbon nanotubes synthesis, properties and applications in modern electronic devices /

Masarapu, Charan. January 2008 (has links)
Thesis (Ph.D.)--University of Delaware, 2008. / Principal faculty advisors: Dennis W. Prather, Dept. of Electrical & Computer Engineering; and Bingqing Wei, Dept. of Mechanical Engineering. Includes bibliographical references.
206

Temporal study of single-walled carbon nanotube carboxylation by nitric acid reflux /

Bajaj, Pooja, January 2008 (has links)
Thesis (M.S.)--University of Texas at Dallas, 2008. / Includes vita. Includes bibliographical references (leaves 55-65)
207

Structure, processing, and properties of polyacrylpnitrile/carbon

Guo, Huina. January 2007 (has links)
Thesis (Ph. D.)--Textile and Fiber Engineering, Georgia Institute of Technology, 2007. / Committee Chair: Satish Kumar; Committee Member: Art Ragauskas; Committee Member: Johannes Leisen; Committee Member: John Muzzy; Committee Member: Samuel Graham.
208

LCVD synthesis of carbon nanotubes and their characterization

Bondi, Scott Nicholas. January 2004 (has links) (PDF)
Thesis (Ph. D.)--Mechanical Engineering, Georgia Institute of Technology, 2005. / Z.L. Wang, Committee Member ; Thomas Starr, Committee Member ; Mostafa Ghiaasiaan, Committee Member ; W. Jack Lackey, Committee Chair; Shreyes Melkote, Committee Member. Vita. Includes bibliographical references.
209

A UHV variable temperature STM and its application to the study of high-T(C) superconductors and carbon nanotubes /

Lee, Jinho, January 2002 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references (leaves 70-77). Available also in an electronic version.
210

A UHV variable temperature STM and its application to the study of high-T(C) superconductors and carbon nanotubes

Lee, Jinho, January 2002 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references.

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