This thesis uses the surface science approach to address questions regarding the interaction of oxygen with platinum and its subsequent reaction with carbon monoxide. A Pt(111) single crystal... Show moreThis thesis uses the surface science approach to address questions regarding the interaction of oxygen with platinum and its subsequent reaction with carbon monoxide. A Pt(111) single crystal surface is used as a model for the catalyst. Chapter 1 provides an overview of the literature on the subject. The description of employed experimental techniques and their backgrounds are presented in Chapter 2. Chapter 3 discusses the adsorption of oxygen on Pt(111) at various temperatures and its role in the oxidation of carbon monoxide. Chapter 4 gives an atomic scale insight into the reaction between adsorbed oxygen and carbon monoxide for different ratios of oxygen and carbon monoxide pressures. In Chapter 5, the reaction between CO and oxygen on Pt(111) was used to register noise in tunneling current due to diffusion and recombination of molecules on the catalytically active surface, to draw conclusions on the most likely rate-limiting step in the process Show less
Spin-crossover compounds showing thermal hysteresis exhibit magnetic and colourmetric bistablility, which is of interest for a number of applications such as information storage and optical... Show moreSpin-crossover compounds showing thermal hysteresis exhibit magnetic and colourmetric bistablility, which is of interest for a number of applications such as information storage and optical displays. Mononuclear iron(II) complexes hold considerable potential in this field, and their cooperative properties may suffer less from size reduction effects than polymeric SCO materials because the coordination environment remains well defined throughout the material. In this thesis, 13 new mononuclear spin-transition materials based on the bapbpy scaffold are described. One of these compounds, [Fe(bbpya)(NCS)2], shows one of the highest transition temperatures (418 K) recorded among known mononuclear SCO complexes. Most interestingly, it keeps a large hysteresis cycle of 21 K in spite of its high transition temperature. Meanwhile, metal dilution study on [Fe(bapbpy)(NCS)2] clearly shows that the two steps and the hysteresis cycles of the SCO are two consequences of the same phenomenon: intermolecular interactions between spin-switching molecules. Finally, a new bapphen-based ligand bearing a 12-carbon alkyl chain at the back of the tetrapyridyl ligand was prepared, which allowed self-assembling the corresponding iron(II) complex on a highly oriented pyrolytic graphite (HOPG) surface. The stable and highly ordered 2D patterns observed by STM are promising for the future study of cooperative spin crossover at surfaces. Show less
A study of the effect of chloride and sulfate anions, as well as of SPS molecules on Cu electrodeposition is presented in this thesis. The deposition process was analyzed by means of a home-built... Show moreA study of the effect of chloride and sulfate anions, as well as of SPS molecules on Cu electrodeposition is presented in this thesis. The deposition process was analyzed by means of a home-built fast electrochemical STM in situ after and during deposition. Show less
This thesis aimed at preparing and characterizing two different model catalysts after their exposure at different temperatures to oxygen, carbon monoxide and hydrogen. The experiments were... Show moreThis thesis aimed at preparing and characterizing two different model catalysts after their exposure at different temperatures to oxygen, carbon monoxide and hydrogen. The experiments were performed in an ultra-high vacuum (UHV) set-up using a range of techniques including scanning tunneling and atomic force microscopy. The first part of the thesis deals with platinum deposited onto highly oriented pyrolytic graphite (HOPG). It was found that a sub-monolayer of the deposited metal on this substrate forms randomly distributed two-/three-dimensional particles. Analysis of the morphology and height distribution of Pt particles on the HOPG(0001) surface after annealing in UHV and in the presence of low pressures of oxygen, carbon monoxide and hydrogen indicates that their growth proceeds via coalescence. The second part of the thesis is devoted to the preparation of model manganese oxide surfaces starting with the MnO(100) surface, which were used as a support for Pt deposits. The preparation of manganese oxide surfaces was based on annealing of MnO(100) single-crystals at different temperatures in UHV and in the presence of argon, oxygen and hydrogen. The first results of Pt deposition on the MnO(100) surface and on this surface altered by annealing in the presence of oxygen and hydrogen are described. Show less
