Interfacial Water at a CO-Predosed Platinum Electrode: A Surface Enhanced Infrared Study with Strong Hydrogen Evolution Reaction Control

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• 作者：Yan-Gang Yan ; Bin Peng ; Yao-Yue Yang ; Wen-Bin Cai ; Andreas Bund ; Ulrich Stimming
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：April 7, 2011
• 年：2011
• 卷：115
• 期：13
• 页码：5584-5592
• 全文大小：1214K
• 年卷期：v.115,no.13(April 7, 2011)
• ISSN：1932-7455

文摘

Attenuated total reflection surface-enhanced infrared absorption spectroscopy, in conjunction with Gram鈭扴chmidt intensity response and 2-dimensional correlation IR analyses, has been extended to study the structure and interaction of interfacial H₂O at a CO-predosed platinum electrode in 0.1 M HClO₄ with its potential navigated from the double-layer region to the strong hydrogen evolution reaction (HER) region. The strong HER enables at least part of the outer interfacial H₂O layers to be effectively expelled by tremendous amounts of H₂ bubbles dynamically formed on the Pt surface. The H₂ bubbles could effectively survive during a fairly fast potential excursion to a positive limit for CO stripping at which a single-beam spectrum was then acquired and used as the reference, facilitating the analysis of 鈥渜uasi-absolute鈥?/i> spectra of the initial interfacial H₂O and CO at the Pt electrode prior to the significant HER. As a result, the broad 谓OH band may be deconvoluted into four peaks at ca. 3630, 3550, 3250, and 3450 cm^鈭?, assignable, respectively, to the innermost H₂O layer with hydrogen bonding broken (H₂O_free) and interacted with the underlying CO adlayer, the second layer of H₂O with hydrogen bonding partially broken, the outer icelike water layers, and the liquid-like water layers. The interaction of H₂O_free with the CO adlayer is much stronger than that expected simply from the hydrophobic effect of the latter as deduced from the stability of rather stable CO and H₂O_free co-structure even with a drastic HER condition, suggesting that a sort of chemical bonding may be involved.