Příprava a charakterizace tenkých vrstev oxidu manganu na povrchu oxidu ceru

Abstract

The ability of catalytic materials to store and release oxygen plays a crucial role in a number of oxidation-reduction reactions. One of the most important materials with this property is cerium oxide, whose properties can be further modified by doping, particularly with a wide range of metals. This bachelor's thesis focuses on manganese doping. The properties of the model catalyst prepared in this way were investigated using STM, NAP- XPS, and LEED methods. Three samples were prepared with different amounts of manganese deposited on a CeO2(111) layer supported on a Pt(111) substrate. The amount of manganese ranged from 0.1 to 2.1 monolayers. STM measurements showed that, after oxidation of these samples, linear manganese oxide structures formed on the surface. Reduction experiments in 0.5 mbar of H2 showed that lower manganese coverage led to a higher degree of cerium reduction in the sample. However, the strongest reduction response, which also began at the lowest temperatures, was observed for the fourth sample, in which manganese was co-deposited together with cerium in an oxygen atmosphere and was therefore distributed throughout the bulk of the layer.

The ability of catalytic materials to store and release oxygen plays a crucial role in a number of oxidation-reduction reactions. One of the most important materials with this property is cerium oxide, whose properties can be further modified by doping, particularly with a wide range of metals. This bachelor's thesis focuses on manganese doping. The properties of the model catalyst prepared in this way were investigated using STM, NAP- XPS, and LEED methods. Three samples were prepared with different amounts of manganese deposited on a CeO2(111) layer supported on a Pt(111) substrate. The amount of manganese ranged from 0.1 to 2.1 monolayers. STM measurements showed that, after oxidation of these samples, linear manganese oxide structures formed on the surface. Reduction experiments in 0.5 mbar of H2 showed that lower manganese coverage led to a higher degree of cerium reduction in the sample. However, the strongest reduction response, which also began at the lowest temperatures, was observed for the fourth sample, in which manganese was co-deposited together with cerium in an oxygen atmosphere and was therefore distributed throughout the bulk of the layer.