Ultrafast proton-coupled electron transfer in heterogeneous photocatalysis

Jin Zhao, Ken Onda, Bin Li, Hrvoje Petek

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

At metal-oxide/protic-solvent interfaces, partially hydrated or "wet electron" states represent the lowest energy pathway for electron transfer. Here we study the photoinduced charge transfer at the H 2O/TiO 2(110) interface by means of time-resolved two-photon photoemission spectroscopy and electronic structure theory. At ∼1 monolayer coverage of H 2O on partially hydroxylated TiO 2 surfaces we find an unoccupied electronic state 2.4±0.1 eV above the Fermi level. Density functional theory shows this to be a two-dimensional "wet electron" state, which is distinct from hydrated electrons observed on water-covered metal surfaces. The decay of electrons from the wet electron state by the resonant charge transfer to the conduction band of TiO 2 occurs in ≤15 femtoseconds. Similar unoccupied electronic structure is observed for CH 3OH covered TiO 2(110) surfaces; however, the electron dynamics are considerably more complex. The wet electron state dynamics of CH 3OH/TiO 2 exhibit both energy and population decay. The excited state lifetime is strongly coverage dependent increasing to >100 fs range above 1 ML CH 3OH coverage. Significantly, a pronounced deuterium isotope effect (CH 3OD) indicates a strong correlation between the interfacial electron transfer and the motion of protons in the molecular overlayer.

Original languageEnglish
Title of host publicationPhysical Chemistry of Interfaces and Nanomaterials V
Volume6325
DOIs
Publication statusPublished - Nov 23 2006
Externally publishedYes
EventPhysical Chemistry of Interfaces and Nanomaterials V - San Diego, CA, United States
Duration: Aug 15 2006Aug 17 2006

Other

OtherPhysical Chemistry of Interfaces and Nanomaterials V
CountryUnited States
CitySan Diego, CA
Period8/15/068/17/06

Fingerprint

Photocatalysis
Electron Transfer
electron states
Protons
electron transfer
Electron energy levels
Electron
methylidyne
protons
Electrons
charge transfer
Electronic structure
Charge transfer
Coverage
electronic structure
Charge Transfer
Electronic Structure
Metals
electrons
decay

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

Cite this

Zhao, J., Onda, K., Li, B., & Petek, H. (2006). Ultrafast proton-coupled electron transfer in heterogeneous photocatalysis. In Physical Chemistry of Interfaces and Nanomaterials V (Vol. 6325). [63250W] https://doi.org/10.1117/12.678279

Ultrafast proton-coupled electron transfer in heterogeneous photocatalysis. / Zhao, Jin; Onda, Ken; Li, Bin; Petek, Hrvoje.

Physical Chemistry of Interfaces and Nanomaterials V. Vol. 6325 2006. 63250W.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Zhao, J, Onda, K, Li, B & Petek, H 2006, Ultrafast proton-coupled electron transfer in heterogeneous photocatalysis. in Physical Chemistry of Interfaces and Nanomaterials V. vol. 6325, 63250W, Physical Chemistry of Interfaces and Nanomaterials V, San Diego, CA, United States, 8/15/06. https://doi.org/10.1117/12.678279
Zhao J, Onda K, Li B, Petek H. Ultrafast proton-coupled electron transfer in heterogeneous photocatalysis. In Physical Chemistry of Interfaces and Nanomaterials V. Vol. 6325. 2006. 63250W https://doi.org/10.1117/12.678279
Zhao, Jin ; Onda, Ken ; Li, Bin ; Petek, Hrvoje. / Ultrafast proton-coupled electron transfer in heterogeneous photocatalysis. Physical Chemistry of Interfaces and Nanomaterials V. Vol. 6325 2006.
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