Direct Electron Transfer of Thiol-Derivatized Tetraphenylporphyrin Assembled on Gold Electrodes in an Aqueous Solution
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- 作者：Qin Wang ; Fupeng Zhi ; Wenting Wang ; Xinghua Xia ; Xiuhui Liu ; Fanfu Meng ; Yanyan Song ; Chen Yang ; Xiaoquan Lu
- 刊名：Journal of Physical Chemistry C
- 出版年：2009
- 出版时间：May 28, 2009
- 年：2009
- 卷：113
- 期：21
- 页码：9359-9367
- 全文大小：304K
- 年卷期：v.113,no.21(May 28, 2009)
- ISSN：1932-7455
文摘
Self-assembled monolayers (SAMs) of thiol-derivatized tetraphenylporphyrin (SH-TPP) and cobalt tetraphenylporphyrin (SH-CoTPP) have been prepared to examine the structure and direct electron transfer (ET) on a gold electrode in an aqueous solution. The cyclic voltammetry peaks of the porphyrin were obviously observed in aqueous solution. An interesting phenomenon was that direct ET cannot occur in phosphate-buffered solutions when a highly oriented and tightly packed monolayer is in existence, but the relatively low-density SH-TPP SAMs exhibited good electrochemical response. The electron transfer rate constants were obtained from the impedance spectra (Cole−Cole plot), upon application of different biasing potentials to the modified electrode. We propose a new kinetic model of the ET processes of SAMs of thiol-derivatized porphyrin and apply the density functional theory (DFT) to study the ET of porphyrin molecules on Au surfaces.