dissertationThis dissertation describes size-dependent investigations of supported palladium and iridium clusters, used as model catalysts for carbon monoxide oxidation and hydrazine decomposition reactions. Chapter 1 provides an introduction into the role of size-dependent studies within the greater scope of catalysis research, with a primary focus on the changing nature of metal particles with size at the small scale (<25 atoms per particle), and the important role of support interactions in determining particle chemistry. An investigation of CO oxidation over TiO2 (110) supported Pdn particles (n = 1,2,4,7,10,16,20,25) via stepwise dosing and reacting protocols is given in Chapter 2, with experimental results showing a correlation between nonmonotonically varying cluster activities and their accompanying electronic properties as a function of size. In Chapter 3, the same catalyst-reaction system is studied as a function of surface temperature and total oxygen exposure during the oxygen dose, and is found to be limited by oxygen binding under the conditions investigated within the previous chapter
