The heterogeneous catalysis by metal oxides is influenced by their surface properties. TiO2 (rutile and anatase) is a widely studied metal oxide which is used for heterogeneous photocatalysis along with many other uses. The photoconversion of CO2 into hydrocarbons on TiO2 surface is of considerable interest. The performance of TiO2 as a catalyst for such reactions requires an understanding of the nature of the interactions between CO2 and TiO2 surfaces, and it is known1 that one important way for CO2 to bind on the TiO2 surface is at surface defect sites created by vacancies at the bridging oxygen sites. There are two main approaches to model the TiO2 surfaces for calculation: slab models using periodic boundary conditions (PBC) and cluster models. Density functional theory (DFT) has been extensively used in conjunction with PBC. But there are errors which appear due to localized unpaired electrons introduced by surface and subsurface defects. It has been found2 with DFT+U calculations, where the parameter U has been used to correct for on-site Coulomb interactions, that with different values of the parameter U there is a crossover in the relative stabilities of the surface and subsurface vacancies. We are using accurate quantum chemical methods including quantum monte carlo (QMC) together with cluster models to assess the performance of DFT calculations.ReferencesFunk, S.; Burghaus, U. Phys. Chem. Chem. Phys. 2006  , 8(41), 4805.Cheng, H. Z.; Selloni, A. J. Chem. Phys. 2009  , 131(5), 054703.

Theoretical study of oxygen vacancies at the TiO<sub>2</sub> surface using cluster models

247th National Meeting (2014)

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Theoretical study of oxygen vacancies at the TiO2 surface using cluster models

Theoretical study of oxygen vacancies at the TiO₂ surface using cluster models