Relationship between permselectivity and the acidity of polyphenols pertaining to the pH response of Pt/polyphenol electrode

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• 作者：Taj ; Shaheen ; Sankarapapavinsam ; S. ; Ahmed ; M.F.
• 关键词：Permselectivity ; Polyphenol-modified electrodes ; Electroreduction ; Diffusion rates ; pH sensors
• 刊名：Synthetic Metals
• 出版年：1998
• 期刊代码：77_03796779
• 类别：ph
• 出版时间：September 30, 1998
• 卷：97
• 期：3
• 页码：205-209
• 文件大小：330 K

摘要

The permselectivity of Pt/polyphenols has been investigated. The selective permeability is found to be different for various polyphenols. Relationships of the diffusion rates, the limiting currents for the reduction of H⁺ ions and the pK_a values of the polyphenols have been established. Electron-withdrawing substituents increase the diffusion rate of the H⁺ ions with increasing acidity of the polyphenol; whereas electron-donating groups bring out the reverse effect. Poly(p-cyanophenol) and poly(2,6-dichlorophenol) are found to be better candidates to modify a Pt electrode for application as pH sensor than existing polyphenol and poly(2,6-dimethylphenol) films.