Wet Electrons at the H2O/TiO2(110) Surface
Abstract
At interfaces of metal oxide and water, partially hydrated or ``wet-electron'' states represent the lowest energy pathway for electron transfer. We studied the photoinduced electron transfer at the H2O/TiO2(110) interface by means of time-resolved two-photon photoemission spectroscopy and electronic structure theory. At ~1-monolayer coverage of water on partially hydroxylated TiO2 surfaces, we found an unoccupied electronic state 2.4 electron volts above the Fermi level. Density functional theory shows this to be a wet-electron state analogous to that reported in water clusters and which is distinct from hydrated electrons observed on water-covered metal surfaces. The decay of electrons from the wet-electron state to the conduction band of TiO2 occurs in <=15 femtoseconds.
- Publication:
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Science
- Pub Date:
- May 2005
- DOI:
- 10.1126/science.1109366
- Bibcode:
- 2005Sci...308.1154O
- Keywords:
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- CHEMISTRY