Stability of [RuII(tpy)(bpy)(OH2)]2+-Modified Graphite Electrodes during Indirect Electrolyses

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• 作者：Florence Geneste ; Claude Moinet ; Soraya Ababou-Girard ; and Francine Solal
• 刊名：Inorganic Chemistry
• 出版年：2005
• 出版时间：June 13, 2005
• 年：2005
• 卷：44
• 期：12
• 页码：4366 - 4371
• 全文大小：138K
• 年卷期：v.44,no.12(June 13, 2005)
• ISSN：1520-510X

文摘

The stability of a graphite felt electrode modified by covalent attachment of [Ru^II(tpy)(bpy)(OH₂)]²⁺ is investigatedduring the indirect electrolyses of alcohols in a flow cell. The continuous increase of the local potential of theelectrode during the electrolyses attests to its degradation. Cyclic voltammetry analyses of the modified electrodeafter electrolyses show a total decrease of 80-90% of the wave corresponding to the Ru^III/II couple. The concentrationof remaining alcohol measured at the outlet of the cell is almost constant during all the electrolyses but increasewhen the potential exceeds 0.95 V_SCE. At low potentials, the electrode can be regenerated by reaction withRu^IICl₂(DMSO)(tpy) and then CF₃SO₃H, followed by hydrolysis, showing that the bipyridine ligand remains covalentlyattached to the electrode. At high potentials, the graphite is oxidized and the catalyst is partly lost in the reactionmedium. XPS analyses of Ru core levels reveal that the ruthenium disappeared after electrolysis, showing that thedegradation of the modified electrode is due to the demetalation of the oxidized complex.