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Non-Band-Gap Photoexcitation of Hydroxylated TiO2.

ABSTRACT: The photochemistry of TiO2 has been studied intensively since it was discovered that TiO2 can act as a photocatalyst. Nevertheless, it has proven difficult to establish the detailed charge-transfer processes involved, partly because the excited states involved are difficult to study. Here we present evidence of the existence of hydroxyl-induced excited states in the conduction band region. Using two-photon photoemission, we show that stepwise photoexcitation from filled band gap states lying 0.8 eV below the Fermi level of rutile TiO2(110) excites hydroxyl-induced states 2.73 eV above the Fermi level that has an onset energy of ∼3.1 eV. The onset is shifted to lower energy by the coadsorption of molecular water, which suggests a means of tuning the energy of the excited state.

SUBMITTER: Zhang Y

PROVIDER: S-EPMC4603613 | biostudies-literature | 2015 Sep

REPOSITORIES: biostudies-literature

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Non-Band-Gap Photoexcitation of Hydroxylated TiO2.

Zhang Yu Y Payne Daniel T DT Pang Chi L CL Fielding Helen H HH Thornton Geoff G

The journal of physical chemistry letters 20150817 17

The photochemistry of TiO2 has been studied intensively since it was discovered that TiO2 can act as a photocatalyst. Nevertheless, it has proven difficult to establish the detailed charge-transfer processes involved, partly because the excited states involved are difficult to study. Here we present evidence of the existence of hydroxyl-induced excited states in the conduction band region. Using two-photon photoemission, we show that stepwise photoexcitation from filled band gap states lying 0.8 ...[more]

PMID: 26267712

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