Development of a Ag/Ag⁺ micro-reference electrode for electrochemical measurements in ionic liquids

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• 作者：Benedikt Huber ; ^a ; ^{huberb@staff.uni-marburg.de"" rel=""nofollow} ; Bernhard Roling^a
• 关键词：Ionic liquid ; Reference electrode ; Quasi-reference electrode ; Micro-reference electrode ; Silver
• 刊名：Electrochimica Acta
• 出版年：2011
• 出版时间：30 July 2011
• 年：2011
• 卷：56
• 期：19
• 页码：6569-6572
• 全文大小：396 K

文摘

We report on a novel miniaturized Ag/Ag⁺ reference electrode (RE) design suitable for electrochemical measurements in room temperature ionic liquids (RTILs). The electrode is based on capillaries with an outer diameter of 365 μm and contains a 10 mmol/l solution of a silver salt in a RTIL. The silver salt bears the same type of anion as the RTIL. While potential shifts of several hundred millivolts have been observed for common platinum or silver pseudo-reference electrodes, our Ag/Ag⁺ micro electrode provides a stable and reliable reference potential over a period of more than two weeks, if protected from light and stored in a nitrogen atmosphere. Due to the small dimensions of the RE, it can be placed close to the working electrode (WE) and it is well-suited for application in electrochemical micro cells as well as for potential-controlled in situ AFM, STM or electrochemical impedance measurements. The electrode characteristics were determined by voltammetric measurements on ferrocene and cobaltocenium hexafluorophosphate dissolved in a RTIL. The highest expected contamination of the sample with Ag⁺ ions was calculated and found to be below 4 ppm.