Preferential oxidation of carbon monoxide in hydrogen-rich gases over supported cobalt oxide catalysts

 

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dc.contributor.advisor Claeys, Michael en_ZA
dc.contributor.advisor Fischer, Nico en_ZA
dc.contributor.author Nyathi, Thulani Mvelo en_ZA
dc.date.accessioned 2016-07-20T12:36:40Z
dc.date.available 2016-07-20T12:36:40Z
dc.date.issued 2016 en_ZA
dc.identifier.citation Nyathi, T. 2016. Preferential oxidation of carbon monoxide in hydrogen-rich gases over supported cobalt oxide catalysts. University of Cape Town. en_ZA
dc.identifier.uri http://hdl.handle.net/11427/20547
dc.description.abstract The preferential oxidation of CO (CO-PROX) has been identified as one route of further reducing the trace amounts of CO (approx. 0.5 - 1 vol%) in the H2-rich reformate gas after the high- and low-temperature water-gas shift reactions. CO-PROX makes use of air to preferentially oxidise CO to CO₂, reducing the CO content to below 10 ppm while minimising the loss of H₂ to H₂O. In this study, a Co₃O₄/γ-Al₂O₃ model catalyst was investigated as a cheaper alternative to the widely used noble metal-based ones. The CO oxidation reaction in the absence of hydrogen has been reported to be crystallite size-dependent when using Co₃O₄ as the catalyst. However, studies looking at the effect of crystallite size during the CO-PROX reaction are very few. Metal-support interactions also play a significant role on the catalyst's performance. Strong metal-support interactions (SMSI) in Co₃O₄/Al2o₃ catalysts give rise to irreducible cobalt aluminate-like species. Under CO oxidation and CO-PROX reaction conditions, such strong interactions in a similar catalyst can have a negative effect on the performance of Co₃O₄ but can keep its chemical phase intact i.e., help prevent the reduction of the Co₃O₄ phase. The catalysts used to investigate these two effects (i.e., crystallite size and metal-support interactions) were synthesised using the reverse micelle technique from which nanoparticles with a narrow size distribution were obtained. Certain properties of the microemulsions prepared were altered to obtain five catalysts with varying Co₃O₄ crystallite sizes averaging between 3.0 and 15.0 nm. Four other catalysts with different metal-support interactions were also synthesised by altering the method for contacting the support with the cobalt precursor. The crystallite size of Co₃O₄ in these four catalysts was kept in the 3.0 - 5.0 nm size range. en_ZA
dc.language.iso eng en_ZA
dc.subject.other Chemical Engineering en_ZA
dc.subject.other Catalysis Research en_ZA
dc.title Preferential oxidation of carbon monoxide in hydrogen-rich gases over supported cobalt oxide catalysts en_ZA
dc.type Master Thesis
uct.type.publication Research en_ZA
uct.type.resource Thesis en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Engineering and the Built Environment
dc.publisher.department Centre for Catalysis Research en_ZA
dc.type.qualificationlevel Masters
dc.type.qualificationname MSc en_ZA
uct.type.filetype Text
uct.type.filetype Image
dc.identifier.apacitation Nyathi, T. M. (2016). <i>Preferential oxidation of carbon monoxide in hydrogen-rich gases over supported cobalt oxide catalysts</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Catalysis Research. Retrieved from http://hdl.handle.net/11427/20547 en_ZA
dc.identifier.chicagocitation Nyathi, Thulani Mvelo. <i>"Preferential oxidation of carbon monoxide in hydrogen-rich gases over supported cobalt oxide catalysts."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Catalysis Research, 2016. http://hdl.handle.net/11427/20547 en_ZA
dc.identifier.vancouvercitation Nyathi TM. Preferential oxidation of carbon monoxide in hydrogen-rich gases over supported cobalt oxide catalysts. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Catalysis Research, 2016 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/20547 en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Nyathi, Thulani Mvelo AB - The preferential oxidation of CO (CO-PROX) has been identified as one route of further reducing the trace amounts of CO (approx. 0.5 - 1 vol%) in the H2-rich reformate gas after the high- and low-temperature water-gas shift reactions. CO-PROX makes use of air to preferentially oxidise CO to CO₂, reducing the CO content to below 10 ppm while minimising the loss of H₂ to H₂O. In this study, a Co₃O₄/γ-Al₂O₃ model catalyst was investigated as a cheaper alternative to the widely used noble metal-based ones. The CO oxidation reaction in the absence of hydrogen has been reported to be crystallite size-dependent when using Co₃O₄ as the catalyst. However, studies looking at the effect of crystallite size during the CO-PROX reaction are very few. Metal-support interactions also play a significant role on the catalyst's performance. Strong metal-support interactions (SMSI) in Co₃O₄/Al2o₃ catalysts give rise to irreducible cobalt aluminate-like species. Under CO oxidation and CO-PROX reaction conditions, such strong interactions in a similar catalyst can have a negative effect on the performance of Co₃O₄ but can keep its chemical phase intact i.e., help prevent the reduction of the Co₃O₄ phase. The catalysts used to investigate these two effects (i.e., crystallite size and metal-support interactions) were synthesised using the reverse micelle technique from which nanoparticles with a narrow size distribution were obtained. Certain properties of the microemulsions prepared were altered to obtain five catalysts with varying Co₃O₄ crystallite sizes averaging between 3.0 and 15.0 nm. Four other catalysts with different metal-support interactions were also synthesised by altering the method for contacting the support with the cobalt precursor. The crystallite size of Co₃O₄ in these four catalysts was kept in the 3.0 - 5.0 nm size range. DA - 2016 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2016 T1 - Preferential oxidation of carbon monoxide in hydrogen-rich gases over supported cobalt oxide catalysts TI - Preferential oxidation of carbon monoxide in hydrogen-rich gases over supported cobalt oxide catalysts UR - http://hdl.handle.net/11427/20547 ER - en_ZA


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