Post-graduate theses
Current Record: 4850 of 6578
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Identifier |
000416611 |
Title |
Study of toxic gases by using n- and p- type composite material |
Alternative Title |
Μελέτη της ανίχνευσης τοξικών αερίων με χρήση n- και p- τύπου σύνθετων υλικών |
Author
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Μοσχογιαννάκη, Μαριλένα Μ.
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Thesis advisor
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Τσιρώνης, Γεώργιος
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Reviewer
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Κυριακίδης, Γεώργιος
Ρεμεδιάκης, Ιωάννης
Μπίνας, Βασίλειος
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Abstract |
In my master thesis work, two series of oxide cpmposites were synthesized, characterized and studied for gas sensing applications, namely; Nickel-Cobalt Vanadates (Ni V2O6, Co0.5Ni0.5 V2O6and Co V2O6) and Nickel-Cobalt Tungstates (NiWO2, Co0.5Ni0.5WO4 and CoWO4). The Vanadates were obtained by an easy and low cost solution based synthetic procedure in which ethylene-glycol was used as a ligand. Tungstates were synthesized with the hydrothermal process. Calcined powders of both series were characterized by X-Ray Powder Diffractometry and Scanning Electron Microscopy.
Tungstates were studied in 4 different gases from toxic to flammable gases such as H2, H2S, NO and acetone. The sensing films were prepared by the spin-coating technique and their gas-sensing performances were studied at operating temperatures ranging from 200 to 350 oC in dry air. The Tungstate sensors (n-type) exhibit low response in these gases and due to the short time of the thesis, they were not studied further. The Vanadate Oxides were also tested in these 4 gases and the Co0.5Ni0.5V2O6 and Co V2O6 sensors exhibit the highest response at 300 oC in H2 gas, namely 11 and 16 respectively.
p-type Co V2O6 nanoparticles were selected and were loaded with 0-2 wt% Palladium (Pd) and systematically investigated for H2- sensing applications. Gas sensing measurements showed that Co V2O6 sensing film with the optimal Pd-loading level of 1wt% exhibited a high response of ~114, which was one order of magnitude higher than that of undoped one, and a short response time of 17s towards 30.000 ppm H2 at an optimum operating temperature of 300 oC. In addition, the optimal Pd-loaded Co V2O6 sensor displayed high H2 selectivity against NO, NO2, H2S and acetone. Thus, Pd- loaded CoV2O6 nanoparticle thick films were proved promising candidates for H2-sensing applications.
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Language |
English |
Subject |
Composite material |
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Gas sensing |
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Gas sensors |
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Metal oxides |
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Αισθητήρες αερίων |
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Ανίχνευση αερίων |
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Οξείδια μετάλλων |
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Σύνθετα υλικά |
Issue date |
2018-07-20 |
Collection
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School/Department--School of Sciences and Engineering--Department of Physics--Post-graduate theses
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Type of Work--Post-graduate theses
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Permanent Link |
https://elocus.lib.uoc.gr//dlib/e/8/6/metadata-dlib-1529568885-813022-10053.tkl
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Views |
729 |