Interplay between small polarons and water on TiO2 surfaces

Ji Chen (Peking U)

Dec 10. 2019, 17:00 — 19:00

By modelling the surface of rutile titania using density functional theory, we discuss the interplay between water and polaronic TiO2 surfaces [1,2]. On one hand we reveal the effect of small surface polarons on water adsorption, dissociation, and hydrogen bonding. The presence of such polarons significantly suppresses dissociation of water molecules that are bonded directly to polaronic sites. Polarons facilitate water dissociation at certain non-polaronic sites. Furthermore, polarons strengthen hydrogen bonds, which in turn affects water dissociation in hydrogen bonded overlayer structures. We also determine that polarons in TiO2 are attracted to the top surface layer by water molecules, which has been supported by experimental measurements. This study reveals that polarons at the rutile surface have complex, multi-faceted, effects on water, highlighting the importance of polarons on water structure and dynamics on such surfaces. We expect that many of the physical properties of surface polarons identified here will apply more generally to surfaces and interfaces that can host small polarons, beyond titania. [1] C. M. Yim et al. J. Phys. Chem. Lett. 9, 4865 (2018) [2] J. Chen et al. arXiv:1908.08008

Further Information
ESI Boltzmann Lecture Hall
Associated Event:
Polarons in the 21st Century (Workshop)
Jozef Devreese (U Antwerpen)
Cesare Franchini (U of Vienna)
Georg Kresse (U of Vienna)
Jacques Tempere (U Antwerpen)