AVS 57th International Symposium & Exhibition
    Surface Science Thursday Sessions
       Session SS-ThA

Paper SS-ThA6
Photochemistry of O2 on Reduced Rutile TiO2(110)

Thursday, October 21, 2010, 3:40 pm, Room Picuris

Session: Environmental Interfaces
Presenter: G.A. Kimmel, Pacific Northwest National Laboratory
Authors: G.A. Kimmel, Pacific Northwest National Laboratory
N. Petrik, Pacific Northwest National Laboratory
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We investigate the adsorption and photon-stimulated reactions of O2 on reduced, rutile TiO2(110). After adsorption at 28 K and annealing to 100 K, at least 85% of the O2 has not dissociated. Typically, less than 50% of this molecularly adsorbed O2 desorbs via hole-mediated reactions during irradiation with ultraviolet (UV) photons. However, UV irradiation dissociates ~20 – 45 % of the chemisorbed O2, which we propose to occur through electron attachment reactions. In addition, weakly bound (physisorbed) O2 readily reacts with chemisorbed O2 during UV irradiation. A simple model based on the oxygen coverage and the charge of the chemisorbed oxygen, which accounts for the observations, is presented. These results show that the photochemistry of oxygen on TiO2(110) is both diverse and more complicated than previously appreciated.