| AVS 55th International Symposium & Exhibition | |
| Surface Science | Monday Sessions |
| Session SS+NC-MoA |
| Session: | Reactivity at Oxide Surfaces |
| Presenter: | Y. Du, Pacific Northwest National Laboratory |
| Authors: | Y. Du, Pacific Northwest National Laboratory Z. Zhang, Pacific Northwest National Laboratory Z. Dohnalek, Pacific Northwest National Laboratory I. Lyubinetsky, Pacific Northwest National Laboratory |
| Correspondent: | Click to Email |
The interaction of molecular oxygen with TiO2 plays a critical role in catalytic activity of TiO2-based materials. It is generally agreed that reactivity of TiO2, partially reduced by a vacuum annealing, is greatly influenced by surface oxygen vacancy defects. In particular, at room temperature, oxygen molecules were believed to dissociate only at vacancy sites with one O atom filling an oxygen vacancy and the other O atom residing at the neighboring Ti site as an adatom. In this talk, we will show that the oxygen dissociation process is much more complicated from our scanning tunneling microscopy studies. We will demonstrate that O vacancies are not the only sites to dissociate O2 and reveal another O2 dissociation channel, where an oxygen molecule dissociates on rows of five-fold coordinated Ti atoms to form an oxgyen adatom pair with two lattice constants spacing. We believe the discovery of the additional O2 dissociation channel could have a considerable impact on the TiO2 surface chemistry. It also calls for a partial reevaluation and/or reinterpretation some of the published experimental and theoretical results.