Toward Highlighting the Ultrafast Electron Transfer Dynamics at the Optically Dark Sites of Photocatalysts

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• 作者：Sophie E. Canton ; Xiaoyi Zhang ; Jianxin Zhang ; Tim B. van Driel ; Kasper S. Kjaer ; Kristoffer Haldrup ; Pavel Chabera ; Tobias Harlang ; Karina Suarez-Alcantara ; Yizhu Liu ; Jorge P茅rez ; Am茅lie Bordage ; M谩ty谩s P谩pai ; Gy枚rgy Vank贸 ; Guy Jennings ; Charles A. Kurtz ; Mauro Rovezzi ; Pieter Glatzel ; Grigory Smolentsev ; Jens Uhlig ; Asmus O. Dohn ; Morten Christensen ; Andreas Galler ; Wojciech Gawelda ; Christian Bressler ; Henrik T. Lemke ; Klaus B. M酶ller ; Martin M. Nielsen ; Reiner Lomoth ; Kenneth W盲rnmark ; Villy Sundstr枚m
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2013
• 出版时间：June 6, 2013
• 年：2013
• 卷：4
• 期：11
• 页码：1972-1976
• 全文大小：353K
• 年卷期：v.4,no.11(June 6, 2013)
• ISSN：1948-7185

文摘

Building a detailed understanding of the structure鈥揻unction relationship is a crucial step in the optimization of molecular photocatalysts employed in water splitting schemes. The optically dark nature of their active sites usually prevents a complete mapping of the photoinduced dynamics. In this work, transient X-ray absorption spectroscopy highlights the electronic and geometric changes that affect such a center in a bimetallic model complex. Upon selective excitation of the ruthenium chromophore, the cobalt moiety is reduced through intramolecular electron transfer and undergoes a spin flip accompanied by an average bond elongation of 0.20 卤 0.03 脜. The analysis is supported by simulations based on density functional theory structures (B3LYP*/TZVP) and FEFF 9.0 multiple scattering calculations. More generally, these results exemplify the large potential of the technique for tracking elusive intermediates that impart unique functionalities in photochemical devices.

Keywords:

electron transfer; photocatalysis; hydrogen evolution; transient X-ray absorption spectroscopy; excited-state structure; ultrafast structural dynamics