Electron-Induced Dissociation of CO2 on TiO2(110)

Abstract

The electron-induced dissociation of CO₂ adsorbed at the oxygen vacancy defect on the TiO₂(110) surface has been investigated at the single-molecular level using scanning tunneling microscopy (STM). Electron injection from the STM tip into the adsorbed CO₂ induces the dissociation of CO₂. The oxygen vacancy defect is found to be healed by the oxygen atom released during the dissociation process. Statistical analysis shows that the dissociation of CO₂ is one-electron process. The bias-dependent dissociation yield reveals that the threshold energy for electron-induced dissociation of CO₂ is 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 CO₂ dissociation.