Elucidating the structures and catalytic properties of metallic nanoparticles

The publications contained within this thesis present the application and development of computational methods for the study of metallic nanoparticles and nanoalloys. Principally these studies are dedicated to their structural characterisation and their interactions with small molecules; vital first steps toward understanding their role in key catalytic processes. Publications have also assessed the applicability of statistical mechanical methods and dispersion corrected DFT to these studies. Palladium-iridium nanoalloys, which are under current investigation for their catalytic properties, are studied extensively using a range of computational methods. Their interactions with hydrogen and benzene are probed in order to better understand their role in tetralin hydroconversion and the preferential oxidation of CO. Structures are revealed to reflect the strongly demixing behaviour of the bulk alloy, with nanosize effects seen in their interactions with hydrogen. The Birmingham Parallel Genetic Algorithm is presented and applied to the direct density functional theory global optimisation of Iridium and both gas-phase and surface supported gold-iridium nanoparticles. The program is shown to be capable of overcoming previous size restrictions while characterising quantum size effects in the iridium and gold-iridium structures. Significant differences are seen between the surface supported and gas-phase gold-iridium structures