Role of steps in the dissociative adsorption of water on rutile TiO2(110)

• Published in: Physical review letters 2013-04, Vol.110 (14), p.146101-146101
• Main Authors: Kristoffersen, H H, Hansen, J O, Martinez, U, Wei, Y Y, Matthiesen, J, Streber, R, Bechstein, R, Lægsgaard, E, Besenbacher, F, Hammer, B, Wendt, S
• Format: Article
• Language: English
• ISSN: 1079-7114
• DOI: 10.1103/PhysRevLett.110.146101

The water-TiO(2) interaction is of paramount importance for many processes occurring on TiO(2), and the rutile TiO(2)(110)-(1×1) surface has often been considered as a test case. Yet, no consensus has been reached whether the well-studied surface O vacancies on the terraces are the only active sites for water dissociation on rutile TiO(2)(110)-(1 × 1), or whether another channel for the creation of H adatoms exists. Here we use high-resolution scanning tunneling microscopy and density functional theory calculations to tackle this long-standing question. Evidence is presented that a second water dissociation channel exists on the surfaces of vacuum-annealed TiO(2)(110) crystals that is associated with the ⟨111⟩ step edges. This second water dissociation channel can be suppressed by blocking of the ⟨111⟩ step edges using ethanol.