Domain-Selective Reactivity of Hydroquinone-Derived Adlayers at Basal Pt(hkl) Single-Crystal Electrodes

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• 作者：Margarita Rodrguez-Lpez ; Antonio Rodes ; Enrique Herrero ; Paulino Tun ; Juan M. Feliu ; Antonio Aldaz ; Arnaldo Carrasquillo ; Jr.
• 刊名：Langmuir
• 出版年：2009
• 出版时间：September 1, 2009
• 年：2009
• 卷：25
• 期：17
• 页码：10337-10344
• 全文大小：918K
• 年卷期：v.25,no.17(September 1, 2009)
• ISSN：1520-5827

文摘

The electrochemical reactivity of hydroquinone-derived adlayers (Q_(ads)) is compared at basal Pt(hkl) single-crystal surfaces, revealing that the electrochemically controlled desorption of Q_(ads) is a highly selective surface reaction. At well-ordered Pt(111) single-crystal surfaces, classical electrochemical methods are combined with in situ SNIFTIRS measurements to demonstrate that the reductive desorption of Q_(ads) and their full oxidative readsorption can be achieved, even in the presence of hydroquinone solution (H₂Q(aq)), by controlling the potential of Pt(111) electrodes. At well-ordered Pt(111) domains, the presence of vertically adsorbed molecules within the Q_(ads) adlayer is deduced from the spectroelectrochemical SNIFTIRS measurements. The desorption mechanism, detected voltammetrically at Pt(111) electrodes, is precluded at well-ordered Pt(110) and Pt(100) single-crystal electrodes immersed in hydroquinone-containing solutions, requiring the presence of well-ordered Pt(111) surface domains in order to be detected. In clean supporting electrolyte, the partial desorption of Q_(ads) layers may take place, but predominantly from minority surface imperfections at Pt(110) and Pt(100) via a different mechanism than at Pt(111) surface domains.