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Study of catalytic reaction waves by SIMS
Jaroš, Antonín ; Willinger, Marc Georg (referee) ; Bábor, Petr (advisor)
Katalytické reakce jsou klíčové pro mnoho technologických oblastí. Abychom docílili jejich zlepšení, je potřeba porozumět jejich mechanismu, k čemuž je důležité vyvíjet nové in-operando techniky. Operando spektroskopie jsou obecně rozděleny do dvou kategorií: velkoplošné techniky, které poskytují zprůměrované informace z celé analyzované oblasti, přičemž nemusí zaznamenat signál z důležitých aktivních míst, a lokalizované techniky, které poskytují informace na atomární úrovni, ovšem nemusí relevantní aktivní místa obsahovat vůbec. V této práci je demonstrováno, že hmotnostní spektrometrie sekundárních iontů je bezprecedentní způsob, jak v reálném čase sledovat oscilační vlny během oxidace CO, poskytující mikro-spektroskopická data, která jsou klíčová pro rozluštění složitého katalytického mechanismu. Ukazuje se, že v nízkých tlacích jsou reakční vlny tvořeny střídajícími se vlnami oxidu platiny a adsorbovaného oxidu uhelnatého. Mechanismus reakce spočívá v redukci oxidu pomocí CO. Navíc jsou oxid platiny a CO adsorbáty nehomogenně rozloženy napříč vln, což je nejvíce patrné na reakční vlnoploše.
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High pressure CO and methanol oxidation study over nanopowders Rare Earth Oxides and platinum thin film catalysts
Rednyk, Andrii ; Matolín, Vladimír (advisor) ; Lykhach, Yaroslava (referee) ; Šmíd, Břetislav (referee)
Title: High pressure CO and methanol oxidation study over nanopowder Rare Earth Oxides and platinum thin film catalysts Author: Mgr. Andrii Rednyk Department: Department of Surface and Plasma Science Supervisor: Prof. RNDr. Vladimír Matolín, DrSc. matolin@mbox.troja.mff.cuni.cz Abstract: This doctoral thesis focuses on reactivity study of nanopowder rare earth oxides (REOs) and platinum based thin film catalysts using microreactor with high pressure reaction cell. REOs nanoparticles were prepared by new approach based on sol-gel chemistry. Magnetron sputtering technique was used for preparation of thin film samples. In the first part of the thesis CO oxidation on REOs and on Pt, PtOx thin films were performed. Among prepared REOs catalyst better activity exhibited alumina stabilized ceria, due to higher surface area. Both Pt and PtOx deposited on silicon substrate exhibited similar activity. When carbon (G-foil or C interlayer) is used as support, activity of Pt thin film decreases while PtOx preserves high activity. In the second part of the thesis steam reforming of methanol (SRM) and partial oxidation of methanol (POM) were performed on Pt thin films. It was shown that PtOx thin film exhibited superior activity compared to other samples with the same thickness. It is due to the reduction of platinum...
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High pressure CO and methanol oxidation study over nanopowders Rare Earth Oxides and platinum thin film catalysts
Rednyk, Andrii ; Matolín, Vladimír (advisor) ; Lykhach, Yaroslava (referee) ; Šmíd, Břetislav (referee)
Title: High pressure CO and methanol oxidation study over nanopowder Rare Earth Oxides and platinum thin film catalysts Author: Mgr. Andrii Rednyk Department: Department of Surface and Plasma Science Supervisor: Prof. RNDr. Vladimír Matolín, DrSc. matolin@mbox.troja.mff.cuni.cz Abstract: This doctoral thesis focuses on reactivity study of nanopowder rare earth oxides (REOs) and platinum based thin film catalysts using microreactor with high pressure reaction cell. REOs nanoparticles were prepared by new approach based on sol-gel chemistry. Magnetron sputtering technique was used for preparation of thin film samples. In the first part of the thesis CO oxidation on REOs and on Pt, PtOx thin films were performed. Among prepared REOs catalyst better activity exhibited alumina stabilized ceria, due to higher surface area. Both Pt and PtOx deposited on silicon substrate exhibited similar activity. When carbon (G-foil or C interlayer) is used as support, activity of Pt thin film decreases while PtOx preserves high activity. In the second part of the thesis steam reforming of methanol (SRM) and partial oxidation of methanol (POM) were performed on Pt thin films. It was shown that PtOx thin film exhibited superior activity compared to other samples with the same thickness. It is due to the reduction of platinum...
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