Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 12 of 12 for “"sulfur poisoning"”.
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Deactivation and enhancement effects of sulfur on supported platinum oxidation catalysts
The effects of sulfur poisoning on the oxidation activity of 1.5 % Pt/[gamma]-Al_2O_3, Pt/TiO_2, Pt/ZrO_2, and Pt/SiO_2, were investigated in this study. Each catalyst was poisoned with an H_2S/air or SO_2/air mixture at 400 C for 24 hours and a sulfur concentration of 200 ppm. The complete …
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Waste to an Asset, H2S to Hydrogen: A DFT Study
… also show that metal oxides are susceptible to sulfur poisoning, which makes their long-term commercial operation challenging. By including surface coverage analysis for S-intermediates, we identify TiO2 as a promising and durable catalyst for H2SOR with 0.49 V calculated overpotential. We also …
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Investigation of accelerated ageing protocols applied to Lean NOx Trap catalysts
… BET. The most significant changes observed were: sulfur poisoning, Pt sintering, ceria sintering and Pd-Pt alloying. Sulfur poisoning was exclusively observed on samples exposed to exhaust gasses. <br/><br/>Chapter III illustrates the experimental procedures and results of the spatially resolved …
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Impedance model of a solid oxide fuel cell for degradation diagnosis
… interface detachment, and anode sulfur poisoning. Detailed electrode-level simulation replaces the traditional equivalent circuit approach, allowing the simulation of degradation mechanisms that alter the shape of the current path. The SOFC impedance results from calculating the …
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First-principles density functional theory study of sulfur oxide chemistry on transition metal surfaces
In this thesis, the chemistry of sulfur oxides on transition metals is studied extensively via first-principles density functional theory (DFT) computations, focusing on the chemical reactivity and selectivity in sulfur poisoning chemical processes that address environmental concerns. The …
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Influence of fuel sulfur content on emissions from diesel engines equipped with oxidation catalysts
… study was a part of the Diesel Emissions Control-Sulfur Effects (DECSE) program that was aimed at determining the impact of diesel fuel sulfur levels on diesel oxidation catalysts that were designed to lower brake-specific PM, HC, and CO emissions from on-highway trucks and buses in the 2002--2004 …
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Atomic Level Study Of Water-Gas Shift Catalysts Via Transmission Electron Microscopy And X-Ray Spectroscopy
… including costly regeneration processes and sulfur poisoning. Extensive research is focused on developing new catalysts to replace the current technology. Supported noble metals stand out as promising candidates, yet comprise intricate nanostructures complicating the understanding of their …
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First-principles approach to screening multi-component metal alloys for hydrogen purification membranes
… including providing high fluxes, resistance to poisoning, long operational standards, and be cost effective. Alloys offer an alternate route in improving upon membranes based on pure metal such as Pd. Development of new membranes is hampered by the large effort and time required not only to …
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Oxidation catalyst degradation in the exhaust stream of a large bore 2-stroke natural gas engine
… post-catalyst. Lubrication oil carry over and poisoning decreases the oxidation catalysts ability to reduce emissions, materials testing was performed to determine the exact levels of the poisons, such as sulfur, phosphorous and zinc. A scanning electron microscope and X-Ray spectrometer were …
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Industrial Ni-Based Catalyst Development for Carbon Dioxide Reforming of Methane
… feed. In the third phase, to understand the sulfur poisoning mechanism, CRM reaction over Ni and Co catalysts in the presence of SO2 was studied. CH4 and CO2 conversions increased and H2 and CO along with the by-products of H2S, elemental sulfur and water were produced as soon as SO2 was …
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Ceramic-Based Anodes for Solid Oxide Fuel Cells
… the basic requirements of SOFCs operating in sulfur-containing hydro-carbon fuels. In this study, both LaGaO3 and LaCrO3-based¬ systems have been explored as anode materials for SOFCs. The results have shown that these two systems are promising anode materials by judicious selection of dopants …
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Surface chemistry of metal oxide materials: from metalorganic and organic reactions to gas sensing
… with the focus on the role of oxygen to avoid sulfur poisoning during the use of a commercial SnO2-based H2S sensor. The commercial H2S sensor is first tested under low vacuum conditions to understand the limitations of this type of sensor operating at different oxygen concentrations. Then the …