A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfillment for the degree of Master of Science in Chemistry, 2017 / The aim of this study was to synthesize helical carbon nanofibers with controlled diameter by
using copper nanoparticles contained inside hollow carbon sphere. In this work, different
methods have been explored to synthesize copper nanoparticles contained inside mesoporous
hollow carbon spheres in order to minimize the sintering effect of the copper nanoparticles.
Mesoporous hollow carbon spheres were used not only as a support for the copper nanoparticles
but to stabilize and disperse these nanoparticles to prevent the formation of aggregates.
Mesoporous hollow carbon spheres were synthesized using a hard templating method, in which
mesoporous silica spheres or polystyrene spheres were used as a sacrificial template. Carbon
nanofibers with different morphologies, including straight and helical fibers were obtained by a
chemical vapor deposition method where acetylene was decomposed over copper nanoparticles
contained inside mesoporous hollow carbon spheres catalyst at 350 °C. The synthesized carbon
nanofibers were grown on the surface of the mesoporous hollow carbon spheres as the methods
used to synthesize the catalyst failed to incorporate copper nanoparticles inside the spheres.
Differences in the diameter of the straight and helical carbon nanofibers were observed from
both catalysts. This supports the important effect of particle size on influencing the shape of the
synthesized carbon nanofibers. / XL2018
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/23629 |
| Date | January 2017 |
| Creators | Magubane, Alice |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | Online resource (xix, 80 leaves), application/pdf |
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