Dresden 2014 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 11: Nanostructures at Surfaces I

O 11.3: Vortrag

Montag, 31. März 2014, 11:00–11:15, WIL C107

Ab-initio simulations of copper-modified titania photocatalysts — •Nicola Seriani — The Abdus Salam ICTP

Titania modified with transition or coinage metals has a great potential as a photocatalyst for the conversion of water and carbon dioxide into hydrocarbons. In particular, copper is interesting for its positive effect on the activity of the system. Still, it is not clear yet what the role of copper is in the overall mechanism, for the photoabsorption, for charge separation and for the chemical reactions taking place on the system. To shed light on these aspects, first-principles simulations based on density functional theory have been performed in three cases: copper doping in bulk titania, small copper clusters on titania surfaces and large particles on titania surfaces. The (101) and (100) surfaces of anatase were considered. Regardless whether copper is present in the bulk or at the surface of titania, its presence has an effect on the local atomic structure of the semiconductor, as well as on the electronic structure of the system. The presence of copper can lead to changes in the edges of valence and conduction bands, but also to the appearance of mid-gap states, depending on the atomic structure of the cluster and the coordination of the copper atoms. Finally, water dissociation has been investigated. These results give an insight over the role of copper in the photoabsorption and in the subsequent steps of the photocatalytic cycle.