Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 41: Poster Session I (Semiconductor Substrates: Epitaxy and growth; Semiconductor Substrates: Adsorbtion; Semiconductor Substrates: Solid-liquid interfaces; Semiconductor Substrates: Clean surfaces; Oxides and insulators: Epitaxy and growth; Oxides and insulators: Adsorption; Oxides and insulators: Clean surfaces; Organic, polymeric and biomolecular films - also with adsorbates; Organic electronics and photovoltaics, Surface chemical reactions; Heterogeneous catalysis; Phase transitions; Particles and clusters; Surface dynamics; Surface or interface magnetism; Electron and spin dynamics; Spin-Orbit Interaction at Surfaces; Electronic structure; Nanotribology; Solid/liquid interfaces; Graphene; Others)

O 41.13: Poster

Dienstag, 23. März 2010, 18:30–21:00, Poster B1

Characterisation of a Titania(TiO₂)-Water-Interface under UV illumination in the Visible Region — •Thomas Kriesche — PCI Universität Heidelberg

Photoassisted reactions on TiO₂ have attracted much interest for e.g. decomposition of organic pollutants in wastewater. As a result of this it is necessary to understand the dynamic surface charge of titania and its interaction with water to better comprehend reactions involved. In situ ATR IR Spectroscopy is a powerful tool used to investigate the interface between TiO₂ and water. Because of the porosity of the titania powder, measurements yield information about dissolved and adsorbed species and their dynamics. LEDs with a wavelength of 350nm for photocatalytic excitation and a ZnSe-ATR-crystal were integrated in a flow cell and used in a Bruker IFS66vS spectrometer. We observed a change in absorption between 9000 and 9500cm⁻¹ during UV-illumination. Additionally, we compare the results with the dynamics of the infrared region using a germanium ATR-crystal. Thin titania layer were deposited on the crystal by dropping a titania-ethanol-mixture on the ATR-surface and annealing it overnight. These layers were observed via SEM. The increase of fundamental knowledge about titania will allow a better understanding of photocatalytic reactions.