In situ scanning tunneling microscopy of 1,6-hexanedithiol, 1,9-nonanedithiol, 1,2-benzenedithiol, and 1,3-benzenedithiol adsorbed on Pt(111) electrodes

Yaw Chia Yang, Yuh Lang Lee, Liang Yueh Ou Yang, Shueh Lin Yau

研究成果: 雜誌貢獻期刊論文同行評審

32 引文 斯高帕斯(Scopus)

摘要

Cyclic voltammetry (CV) and in situ scanning tunneling microscopy (STM) were used to examine four dithiol molecules, including 1,6-hexanedithiol, 1,9-nonanedithiol, 1,2-benzenedithiol, and 1,3-benzenedithiol, adsorbed on well-ordered Pt(111) electrodes in 0.1 M HClO4. The open-circuit potential (OCP) of Pt(111) electrodes decreased substantially from 0.95 to 0.3 V (versus reversible hydrogen electrode) upon the adsorption of dithol molecules, which indicates that these adsorbates injected electrons into the Pt electrode. For all dithiol molecules, ordered adlattices of p(2 × 2) and (√3 × √3)R30° were formed when the dosing concentration was lower than 150μM and the potential of Pt(111) was more negative than 0.5 V. Raising the potential of Pt(111) from 0.1 to 0.4 V or more positive values could transform p(2 × 2) to (√3 × √3)R30° before it turned disarray. The insensitivity of the structure of dithiol adlayers with their chemical structures was explained by upright molecular orientation with the formation of one Pt-S bond per dithiol molecule. This molecular orientation was independent of the coverage of dithiol molecules, as nucleation seeds produced at the beginning of adsorption were also constructed with p(2 × 2). The triangular-shaped STM molecular resolution suggested 3-fold binding of sulfur headgroup on Pt(111). All dithiols were adsorbed so strongly on Pt(111) electrodes that switching the potential negatively to the onset of hydrogen evolution in 0.1 M HClO4 or water reduction in 1 M KOH could not displace dithiol admolecules.

原文???core.languages.en_GB???
頁(從 - 到)5189-5195
頁數7
期刊Langmuir
22
發行號11
DOIs
出版狀態已出版 - 23 5月 2006

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