Carbon nitride-based catalysts for thermal carbon monoxide oxidation: Does phase matter?
| dc.contributor.author | Mohamed, Ahmed Gamal Abdelmoneim | |
| dc.contributor.supervisor | Ozoemena, Kenneth Ikechukwu | |
| dc.contributor.supervisor | Abdullah, Aboubakr M. | |
| dc.contributor.supervisor | Eid, Kamel | |
| dc.date.accessioned | 2024-11-16T17:11:53Z | |
| dc.date.available | 2024-11-16T17:11:53Z | |
| dc.date.issued | 2023-06 | |
| dc.description | A dissertation submitted in fulfilment of the requirements for the degree of Master of Science, to the Faculty of Science, School of Chemistry. University of the Witwatersrand, Johannesburg, 2023. | |
| dc.description.abstract | Carbon monoxide (CO) has a poisonous effect on all living organisms as it binds to the hemoglobin of blood cells, preventing oxygen uptake. Thus, the conversion of CO to less dangerous gas such as CO2 is an essential process. This work presented the utilization of carbon nitrides (C3Nx) in different phases (βgC3N4, βC3N5, βC3N6) for thermal carbon monoxide (CO) oxidation. Herein, gC3N4, C3N5, and C3N6 were prepared by pyrolysis of their amine precursors, which were doped with Fe by two distinct methods; mechanical mixing (Fe/C3Nx-M) and polymerization (Fe/C3Nx-P). The controlled preparation of Fe/gC3N4-P allowed the formation of hierarchical porous structures with high surface area (219 m2/g) compared to the Fe/gC3N4-M (77 m2/g). This enabled the ease of reactants diffusion, enhanced the electron transfer, and maximized the atomic utilization. Accordingly, Fe/gC3N4-P (T100= 245 °C) presented higher catalytic activity than Fe/gC3N4-M (T100= 291 °C). In addition, bimetallic FeTi/gC3N4-P and trimetallic FeTiCu/gC3N4-P catalysts achieved the complete conversion of carbon monoxide (CO) at lower temperatures; 175 and 147 °C, respectively, which was attributed to the enhanced reducibility, and synergistic effect of Ti and Cu. Besides, FeTi/gC3N4-P and FeTiCu/gC3N4-P showed higher catalytic activity than Pd/C commercial catalyst (T100= 198 °C). In addition, the trimetallic FeTiCu/gC3N4-P showed a stable catalytic behavior without any deactivation for more than ten hours. This study showed that the C3Nx phases worked successfully in the thermal catalytic CO oxidation. However, the gC3N4 phase is the most active one when doped with metal(s), as it offered higher crystallinity, graphitization, and thermal stability than C3N5 and C3N6. This study also paves the way for the utilization of gC3N4 as a support for different metals to be used efficiently in various thermal catalytic applications, not only CO Oxidation. | |
| dc.description.submitter | MMM2024 | |
| dc.faculty | Faculty of Science | |
| dc.identifier | 0000-0001-5440-2396 | |
| dc.identifier.citation | Ahmed Gamal Abdelmoneim. (2023). Carbon nitride-based catalysts for thermal carbon monoxide oxidation: Does phase matter? [Master's dissertation, University of the Witwatersrand, Johannesburg]. https://hdl.handle.net/10539/42622 | |
| dc.identifier.uri | https://hdl.handle.net/10539/42622 | |
| dc.language.iso | en | |
| dc.publisher | University of the Witwatersrand, Johannesburg | |
| dc.rights | ©2023 University of the Witwatersrand, Johannesburg. All rights reserved. The copyright in this work vests in the University of the Witwatersrand, Johannesburg. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of University of the Witwatersrand, Johannesburg. | |
| dc.rights.holder | University of the Witwatersrand, Johannesburg | |
| dc.school | School of Chemistry | |
| dc.subject | Catalyst | |
| dc.subject | Carbon monoxide (CO) | |
| dc.subject | Carbon nitride | |
| dc.subject | Carbon monoxide (CO) oxidation | |
| dc.subject | UCTD | |
| dc.subject.other | SDG-13: Climate action | |
| dc.title | Carbon nitride-based catalysts for thermal carbon monoxide oxidation: Does phase matter? | |
| dc.type | Dissertation |