High-pressure STM studies of oxidation catalysis

The main theme of this thesis is the catalytic oxidation of CO, which we have investigated on several model catalyst surfaces at atmospheric pressures and elevated temperatures with the combination of Scanning Tunneling Microscopy and Mass Spectrometry.The study of CO oxidation on low-index and vicinal palladium surfaces has shown that when exposed to ambient pressures of oxygen at elevated temperature, these surfaces oxidize irrespective of their orientation. In this pressure regime the oxides were shown to have a higher reactivity than the metallic surfaces.In a certain window of partial pressure combinations of O2 and CO reaction rate oscillations were observed on Pd(100) and on its vicinal surface Pd(1.1.17). ). CO adsorption on Pt(111) was found to lead to the formation of a regular overlayer structure, identified as (√19 x √19) R23.4°-13CO. The stability of this structure under different reaction conditions was discussed. These results were further used to illustrate the importance of temperature in a catalytic system.Spectacularly high conversion rates could be achieved during CO oxidation at atmospheric pressure on metallic Pt(100) surface.​​​​​​​This work is part of the research programme of the Stichting voor Fundamenteel Onderzoek der Materie (FOM), which is financially supported by the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO).UBL - phd migration 201