P6: Influence of defects and environment on photo-catalytic properties of TiO2

Supervision:Susan Köppen, Thomas Frauenheim

Motivation and state of the art:  The invasive use of technically relevant aqueous organic pollutants in agricultural sector and veterinary medicine cause efficient pathways for the optimization of photo degradation processes on TiO2 and therefore an understanding of photochemical reactions under environmental conditions. The complexity of the interface systems motivates the development of novel “light sensitive” classical potentials on the basis of accurate quantum methods.

Own work: The applied simulation techniques used in recent studies span from density functional theory (DFT) to classical force field methods (FF). DFT simulations are used to parameterize complex surface models of various metal oxides on the classical level. The adsorption of various biomolecules at different size scales is analyzed qualitatively as well as quantitatively.

Aims and work plan: This project aims at the development of novel “light-sensitive” classical potentials which will give the possibility to carry out large scale simulations with and without light irradiation conditions. Initially the electronic properties of different titania surface models will be studied in cooperation with P7 and P9 and used to parameterize pH dependent molecule/water/TiO2 interfacial potentials. Appropriate additional terms of novel “light-sensitive” classical potentials will be implemented to distinct between the ground (GS) and excited state (ES) on the basis of the knowledge of P9 and P8. In correlation with P8 and P7, the large scale simulations of TiO2/ water – ion/ adsorbate reference systems will be performed with small pollutant molecules and representatives of the pesticides/insecticides.