Interplay between Adsorbates and Polarons: CO on Rutile TiO2(110)

Author(s)
Michele Reticcioli, Igor Sokolovic, Michael Schmid, Ulrike Diebold, Martin Setvin, Cesare Franchini
Abstract

Polaron formation plays a major role in determining the structural, electrical, and chemical properties of ionic crystals. Using a combination of first-principles calculations, scanning tunneling microscopy, and atomic force microscopy, we analyze the interaction of polarons with CO molecules adsorbed on the reduced rutile TiO2(110) surface. Adsorbed CO shows attractive coupling with polarons in the surface layer, and repulsive interaction with polarons in the subsurface layer. As a result, CO adsorption depends on the reduction state of the sample. For slightly reduced surfaces, many adsorption configurations with comparable adsorption energies exist and polarons reside in the subsurface layer. At strongly reduced surfaces, two adsorption configurations dominate: either inside an oxygen vacancy, or at surface Ti-5c, sites, coupled with a surface polaron. Similar conclusions are predicted for TiO2(110) surfaces containing near-surface Ti interstitials. These results show that polarons are of primary importance for understanding the performance of polar semiconductors and transition metal oxides in catalysis and energy-related applications.

Organisation(s)
Computational Materials Physics
External organisation(s)
Center for Computational Materials Science, Technische Universität Wien, Università degli Studi di Bologna
Journal
Physical Review Letters
Volume
122
No. of pages
6
ISSN
0031-9007
DOI
https://doi.org/10.1103/PhysRevLett.122.016805
Publication date
01-2019
Peer reviewed
Yes
Austrian Fields of Science 2012
Materials physics, Surface physics
Keywords
Portal url
https://ucris.univie.ac.at/portal/en/publications/interplay-between-adsorbates-and-polarons-co-on-rutile-tio2110(c080d04c-7eeb-45bd-8d98-07531ed4a46d).html