Electrochemical Properties and Analytical Applications of Keggin-type Phosphomolybdic Anions in Electrostatically Linked 2-Aminoethanethiol Self-Assembled Monolayers |
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Authors: | Shengfu Wang Yixin Sun Xianglin Wang Xiuhua Zhang |
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Institution: | (1) Faculty of Chemistry and Material Science, Hubei University, 430062 Wuhan, P.R. China |
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Abstract: | A composite film containing a heteropolyanion was prepared on a 2-aminoethanethiol (AT) self-assembled monolayer film-modified gold electrode by attaching the Keggin-type phosphomolybdic anion. The surface structures and electrochemical properties of the composite films were characterized by using ATR-FTIR, AC impedance, cyclic voltammetry and chronocoulometry. FTIR studies indicated that there was some electrostatic interaction between Pmo12O427– and surface NH3+. Three reversible redox couples were observed in 1.0 mol L–1 H2SO4 in the potential range of 0–0.7 V for the composite film modified electrode, which were attributed to two-electron and two-proton electrochemical processes of PMo12O427–. The diffusion coefficient is determined to be 2.04×10–7 cm2 s–1. The composite film shows good catalytic activities for the reduction of nitrite (NO2–) in acidic solution and the catalytic mechanisms are described. The modified electrode provides a linear response for NO2– in the concentration range of 1.0×10–4 to 1.0×10–7 mol L–1 by differential pulse adsorptive stripping voltammetry with a correlation coefficient of 0.9965. The detection limit (three times the signal blank/slope) was 2.0×10–8 mol L–1. The modified electrode was used for the determination of NO2– in wastewater. |
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Keywords: | : 2-aminoethanethiol Keggin-type phosphomolybdic anions sensor nitrite sensor |
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