Adsorbate-Induced Modification of Surface Electronic Structure: Pyrocatechol Adsorption on the Anatase TiO2 (101) and Rutile TiO2 (110) Surfaces

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• 作者：Karen L. Syres ; Andrew G. Thomas ; Wendy R. Flavell ; Ben F. Spencer ; Federica Bondino ; Marco Malvestuto ; Alexei Preobrajenski ; Michael Gr盲tzel
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：November 8, 2012
• 年：2012
• 卷：116
• 期：44
• 页码：23515-23525
• 全文大小：478K
• 年卷期：v.116,no.44(November 8, 2012)
• ISSN：1932-7455

文摘

Photoemission and near-edge X-ray absorption fine structure (NEXAFS) techniques have been used to study the adsorption of pyrocatechol on anatase TiO₂ (101) and rutile TiO₂ (110) single crystals. Photoemission results suggest the pyrocatechol molecule adsorbs on both surfaces predominantly in a bidentate geometry. Using the searchlight effect, the carbon K-edge NEXAFS spectra recorded for pyrocatechol on anatase TiO₂ (101) and rutile TiO₂ (110) show the phenyl rings in the pyrocatechol molecule to be oriented at 27 卤 6掳 and 23 卤 8掳, respectively, from the surface normal. Experimental data and computational models of the pyrocatechol鈥揳natase TiO₂ interface indicate the appearance of new occupied and unoccupied states on adsorption due to hybridization between the electronic states of the pyrocatechol molecule and the surface. The atomic character of the new orbitals created facilitates direct photoinjection from pyrocatechol into anatase TiO₂ and induces a strong final state effect in the carbon K-edge NEXAFS spectrum.