| AVS 55th International Symposium & Exhibition | |
| Surface Science | Monday Sessions |
| Session SS+NC-MoA |
| Session: | Reactivity at Oxide Surfaces |
| Presenter: | I. Lyubinetsky, Pacific Northwest National Laboratory |
| Authors: | Y. Du, 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–based materials affects many chemical and photochemical processes. We will present our recent discoveries in studying O2 interaction with reduced TiO2(110) surface by scanning tunneling microscopy at 300K. By tracking the same surface area before and after O2 exposure, we confirm the known O2 dissociation channel occuring at the bridging oxygen vacancy (Ovac) sites, with one O atom healing an Ovac and other O bonding at the neighboring Ti site as an adatom (Oa). In addition, the lateral distribution and diffusion of Oa are studied. It is revealed that there are three possible configurations for the Oa in regarding to the position of the original Ovac site, which can not be explained by thermal diffusion. Through detailed study, we conclude that observed distribution of the O adatoms is attained through a nonthermal, transient mobility from the energy release during dissociation. Unlike for other known cases of the dissociation of diatomic molecules where both “hot” adatoms accommodate at equivalent sites, in this study, the O atoms filling the vacancies are locked into the bridging oxygen rows and only the O adatoms are relatively free to move. The transient motion of the hyperthermal O adatoms might bring an enhanced reactivity, thus affect surface chemistry.