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Optimization of processing parameters in the preparation of hematite thin films for photoelectrochemical water splitting
Dissertation (MSc (Physics))--University of Pretoria, 2022.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2022
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| _version_ | 1867613576205697024 |
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| access_status_str | Open Access |
| author2 | Diale, M. (Mmantsae Moche) |
| author_browse | Diale, M. (Mmantsae Moche) |
| author_facet | Diale, M. (Mmantsae Moche) |
| collection | Thesis |
| dc_rights_str_mv | © 2022 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MSc (Physics))--University of Pretoria, 2022. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/86584 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:38:20.548Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2022 |
| publishDateRange | 2022 |
| publishDateSort | 2022 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/86584 Optimization of processing parameters in the preparation of hematite thin films for photoelectrochemical water splitting Diale, M. (Mmantsae Moche) adielholtzhausen@gmail.com Nombona, Nolwazi Holtzhausen, Adiel Physics Optical studies Ramam microspectroscopy SRD analysis Electronic properties UCTD Dissertation (MSc (Physics))--University of Pretoria, 2022. In this study, the influence of coating techniques and layering of hematite (α-Fe2O3) thin films were studied. Two colloidal-based coating techniques namely dip coating and thermal spray pyrolysis were used to synthesize nanostructured hematite thin films. All films were annealed at 500 °C for I hr to perform the calcination from ɣ- Fe2O3 (magnetite) to α-Fe2O3 (hematite). X-ray diffraction confirmed the calcination to hematite, it furthermore confirmed the hexagonal corundum structure of hematite. Raman spectroscopy confirmed the polycrystallinity of hematite with seven optical vibrational modes (two Eg and five A1g) observed in the first Brillouin zone. Ultraviolet-visible spectroscopy showed good absorbance in the visible region with absorbance onset ranging from 596.75 – 608.75 nm. Scanning electron microscopy depicted various nanoparticles ranging from agglomerated nanodiscs and nanorods to nanospheres. This study showed that coating techniques could attribute to the optical and structural properties of hematite thin films for photoelectrochemical water splitting. Furthermore, a modified annealing approach was used to determine the effects of annealing time and multiple layer formation on the structural, optical and electronic properties of hematite thin films. Scanning electron microscopy revealed an increase in film thickness with increased annealing time. Furthermore, it depicted the formation of four single layers when annealing between each coating. UV-Vis indicated a decrease in bandgap with prolonged annealing. Additionally, UV-Vis revealed better absorption for coherent layers when compared to the single layers annealed four times. The photocurrent increased two-fold from 1.65 x 10-4 Acm-2 to 4.77 x 10-4 Acm-2 when annealing time was increased from 30 mins to 1 hr. Similarly, a significant improvement from 2.26 x 10-4 Acm-2 to 4.35 x 10-4 Acm-2 was found with a decrease of multiple layer formation and annealing frequency. From this work it was determined that annealing time and multiple layer formation by increased annealing frequency influences the optical, structural and electrical properties of nanostructured hematite thin films. NRF (National Research Foundation) Physics MSc (Physics) Unrestricted 2022-07-29T07:02:45Z 2022-07-29T07:02:45Z 2022-09 2022-12 Dissertation Holtzhausen, A 2022, Optimization of processing parameters in the preparation of hematite thin films for photoelectrochemical water splitting, MSc Dissertation, University of Pretoria, Pretoria S2022 https://repository.up.ac.za/handle/2263/86584 https://doi.org/10.25403/UPresearchdata.20390721 en © 2022 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | Physics Optical studies Ramam microspectroscopy SRD analysis Electronic properties UCTD Optimization of processing parameters in the preparation of hematite thin films for photoelectrochemical water splitting |
| title | Optimization of processing parameters in the preparation of hematite thin films for photoelectrochemical water splitting |
| title_full | Optimization of processing parameters in the preparation of hematite thin films for photoelectrochemical water splitting |
| title_fullStr | Optimization of processing parameters in the preparation of hematite thin films for photoelectrochemical water splitting |
| title_full_unstemmed | Optimization of processing parameters in the preparation of hematite thin films for photoelectrochemical water splitting |
| title_short | Optimization of processing parameters in the preparation of hematite thin films for photoelectrochemical water splitting |
| title_sort | optimization of processing parameters in the preparation of hematite thin films for photoelectrochemical water splitting |
| topic | Physics Optical studies Ramam microspectroscopy SRD analysis Electronic properties UCTD |
| url | https://repository.up.ac.za/handle/2263/86584 https://doi.org/10.25403/UPresearchdata.20390721 |