Thesis ( M.Sc)--University of the Witwatersrand, Faculty of Science, 2003 / Initial investigations at Mintek, into the addition of gold to commercial hopcalite
(CuxMnyOz), showed that it improved the activity of hopcalite. So this study was
initially focused on investigating Aulhopcalite catalysts further. Also, since according
to literature, MnxOy has catalytic potential, the study of AulMnxOy catalysts was
included.
Au/hopcalite and Aul/nxOy catalysts were made by means of deposition-precipitation,
colloidal gold deposition and co-precipitation. Only one catalyst-type
was highly active at room temperature - the co-precipitated Au/MnxOy catalysts. The
optimised co-precipitated Au/MnxOy catalysts were more active than all the other
catalysts by at least an order of magnitude. So the study focus changed, to make the
optimisation of AulMnxOy catalysts a priority.
Cerium is a well-known promoter on MnxOy catalysts, and so was also added to the
co-precipitated Au/MnxOy catalysts. However, even small amounts of cerium had an
adverse effect on the catalysts' activities.
The compaction and crushing of a co-precipitated Au/MnxOy catalyst to obtain
granules of larger particle size than the powders, was also carried out. The activities
and surface areas of the catalysts were found to be comparable. This augers well for
industrial purposes, since the use of powdered catalysts in industry is not viable.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/18804 |
| Date | January 2015 |
| Creators | Padayachee, Diandree |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
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