AVS 58th Annual International Symposium and Exhibition
    Surface Science Division Tuesday Sessions
       Session SS1-TuM

Paper SS1-TuM10
Adsorption and Electron-induced Dissociation of CO2 on TiO2(110)

Tuesday, November 1, 2011, 11:00 am, Room 109

Session: Chemisorption & Surface Reactions
Presenter: Junseok Lee, National Energy Technology Laboratory
Authors: J. Lee, National Energy Technology Laboratory
X. Deng, National Energy Technology Laboratory
D. Sorescu, National Energy Technology Laboratory
Correspondent: Click to Email
Adsorption and electron-induced reaction of CO2 on the TiO2(110) surface has been investigated using scanning tunneling microscopy (STM) and dispersion corrected density functional theory (DFT). At low coverage the adsorption of CO2 takes place at the oxygen vacancy defect. At higher coverage the CO2 starts to adsorb on the Ti rows. The DFT results show that the CO2 at the oxygen vacancy defect is in a tilted configuration and the molecular axis is perpendicular to the bridging oxygen row. On the Ti row, the DFT results confirm that the CO2 adsorbs in a flat configuration with its axis parallel to the bridging oxygen row. Electron injection from the STM tip into the CO2 at the oxygen vacancy defect induces the dissociation of CO2. The oxygen vacancy defect is found to be healed by the O atom released during the CO2 dissociation process. Statistical analysis shows that the dissociation of CO2 is a one-electron driven process with a threshold voltage of 1.4 eV above the conduction band minimum of TiO2. The formation of a transient negative ion by the injected electron is considered to be the key process in the CO2 dissociation.