کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
195756 459821 2007 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Adsorption dynamics and interfacial properties of thiol-based cobalt terpyridine monolayers
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
پیش نمایش صفحه اول مقاله
Adsorption dynamics and interfacial properties of thiol-based cobalt terpyridine monolayers
چکیده انگلیسی

Spontaneously adsorbed monolayers of [Co(ttp-CH2-SH)2](PF6)2 have been formed on platinum microelectrodes by exposure to micromolar solutions of the complex in 0.1 M TBABF4 in acetonitrile, ttp-CH2-SH is 4′-(p-(thiolmethyl)-phenyl)-2,2′:6′,2″-terpyridine. Resonance Raman spectroscopy on roughened polycrystalline platinum macro electrodes show that the molecule undergoes adsorption through the sulphur atom onto the platinum surface. The monolayers show reversible and well defined cyclic voltammetry when switched between Co2+ and Co3+ forms, with a peak to peak splitting of 0.040 ± 0.005 V up to 200 V s−1 and an FWHM of 0.138 ± 0.010 V. Adsorption is irreversible leading to the maximum surface coverage, 6.3 ± 0.3 × 10−11 mol cm−2 for 2.5 ≤ [Co(ttp-CH2-SH)2] ≤ 10 μM. The rate of monolayer formation appears to be controlled not by mass transport or interfacial binding but by surface diffusion of the complex. The surface diffusion coefficient is 5.5 ± 1.1 × 10−7 cm2 s−1 indicating that prior to formation of an equilibrated monolayer, the adsorbates have significant mobility on the surface. The electron transfer process across the monolayer–electrode interface has been probed by high speed chronoamperometry and the standard heterogeneous electron transfer rate constant, k°, is approximately 3.06 ± 0.03 × 104 s−1. The reorganization energy is at least 18.5 kJ mol−1.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Electrochimica Acta - Volume 52, Issue 24, 1 August 2007, Pages 6692–6699
نویسندگان
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