dc.contributor.advisor | Van Sittert, C.G.C.E. | |
dc.contributor.advisor | Ungerer, M.J. | |
dc.contributor.author | Nel, Theunis | |
dc.date.accessioned | 2021-11-23T11:09:03Z | |
dc.date.available | 2021-11-23T11:09:03Z | |
dc.date.issued | 2021 | |
dc.identifier.uri | https://orcid.org/0000-0002-2242-0773 | |
dc.identifier.uri | http://hdl.handle.net/10394/37905 | |
dc.description | MSc (Chemistry), North-West University, Potchefstroom Campus | en_US |
dc.description.abstract | Lately, significant interest has risen towards the development of renewable energy in order to
lower fossil fuel consumption and its environmental impact. Hydrogen (H2) has been proposed as
a viable alternative to fossil fuels due to its high energy per unit mass, as well as its low
environmental impact. Despite numerous methods that exist for obtaining H2, production of H2 is
often difficult. Among various viable processes utilised to produce H2, is the Hybrid Sulphur (HyS)
cycle wherein sulphur dioxide (SO2) and water (H2O) is thermo-electrochemically converted into
sulphuric acid (H2SO4) and H2. Platinum (Pt) has proven to be an efficient catalyst for the HyS
cycle, producing a high purity of H2. However, uncertainties regarding SO2-H2O interaction on the
Pt surface persist, complicating efforts towards the development of catalyst with high efficiency.
Although various experimental investigations have been performed, no absolute conclusions
regarding the HyS cycle mechanism have thus far been made. Since little is still understood
regarding the fundamental description of the HyS cycle, and in particular, the interaction between
SO2 and H2O on the Pt surface, this dissertation fundamentally investigates the energetic and
electronic properties of co-adsorbed SO2 and H2O on a Pt surface. Through density functional
theory (DFT) analysis, it is observed that the adsorption of H2O on the Pt surface is significantly
influenced by the presence of pre-adsorbed SO2, both in terms of adsorption energy and
adsorption geometry. In addition, when comparing the influence of pre-adsorbed SO2 and preadsorbed
H2O on the H2O adsorption process, it is observed that H2O adsorption is influenced
more by pre-adsorbed SO2 than by pre-adsorbed H2O.
Furthermore, the adsorption of other sulphur containing species such as sulphur monoxide SO
and sulphuric acid H2SO4 (both cis- and trans-isomers), as well as the adsorption of H2 on Pt(111)
are discussed. The co-adsorption of H2SO4 and H2 on Pt(111) is also discussed and compared
to the co-adsorption of SO2 and H2O.
Finally, possible SO2 oxidation mechanisms for the HyS reaction on Pt(111) were investigated.
Both the Eley-Rideal and Langmuir-Hinshelwood mechanisms were evaluated on pristine Pt(111)
with the former mechanism identified as occurring by preference. | en_US |
dc.language.iso | en | en_US |
dc.publisher | North-West University (South Africa) | en_US |
dc.subject | Hybrid sulphur cycle | en_US |
dc.subject | Platinum | en_US |
dc.subject | Sulphur dioxide | en_US |
dc.subject | Adsorption | en_US |
dc.subject | Co-adsorption | en_US |
dc.subject | Oxidation mechanism | en_US |
dc.title | Sulphur dioxide oxidation mechanism on Pt surfaces : a DFT study | en_US |
dc.type | Thesis | en_US |
dc.description.thesistype | Masters | en_US |
dc.contributor.researchID | 10073817 - Van Sittert, Cornelia Gertina Catharina Elizabeth (Supervisor) | |
dc.contributor.researchID | 20068980 - Ungerer, Maria Johanna (Supervisor) | |