Tunable Electric Field Enhancement and Redox Chemistry on TiO2 Island Films via Covalent Attachment to Ag or Au Nanostructures

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• 作者：Arumugam Sivanesan ; Khoa H. Ly ; Witold Adamkiewicz ; Konstanze Stiba ; Silke Leimk眉hler ; Inez M. Weidinger
• 刊名：The Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：June 6, 2013
• 年：2013
• 卷：117
• 期：22
• 页码：11866-11872
• 全文大小：391K
• 年卷期：v.117,no.22(June 6, 2013)
• ISSN：1932-7455

文摘

Ag鈥揟iO₂ and Au鈥揟iO₂ hybrid electrodes were designed by covalent attachment of TiO₂ nanoparticles to Ag or Au electrodes via an organic linker. The optical and electronic properties of these systems were investigated using the cytochrome b₅ (Cyt b₅) domain of sulfite oxidase, exclusively attached to the TiO₂ surface, as a Raman marker and model redox enzyme. Very strong SERR signals of Cyt b₅ were obtained for Ag-supported systems due to plasmonic field enhancement of Ag. Time-resolved surface-enhanced resonance Raman spectroscopic measurements yielded a remarkably fast electron transfer kinetic (k = 60 s^鈥?) of Cyt b₅ to Ag. A much lower Raman intensity was observed for Au-supported systems with undefined and slow redox behavior. We explain this phenomenon on the basis of the different potential of zero charge of the two metals that largely influence the electronic properties of the TiO₂ island film.