Analytical Sciences

Electrochemical Characteristic of 2-MercaptobenzothiazoleSelf-Assembled Monolayer on Gold

Jun WANG, Baizhao ZENG, Cheng FANG, and Xingyao ZHOU

Department of Chemistry, Wuhan University, Wuhan 430072, P. R. China

A monolayer membrane of 2-mercaptobenzothiazole (MBT) was prepared on a gold electrode through a self-assemblyprocedure. The monolayer structure and the electrochemical properties were investigated by various electrochemicaltechniques, like cyclic voltammetry and an impedance measurement with external redox. Experiments show that MBTcan form a closely packed monolayer that can be charged due to the active N atom. The amount of charge on themembrane surface varies with the solution pH, and the monolayer shows "opening and closing" which depends on thesolution pH. The electrostatic interaction of the monolayer with other ions is also related to the pH in solution. Animpedance analysis shows that the heterogeneous electron-transfer rate of a fast redox like Fe(CN)₆^3-/4- decreases from 1.2qے0^-2 to 4.7 qے0^-5 cm s^-1 in neutral solution due to blockage of the self-assembled monolayer membrane.

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