An EQCM study of corrosion and complexation at electrode surfaces. Oxidation of silver in the presence of 4,4′-bipyridyl

Wilde, C. Paul; Pisharodi, Devi

doi:10.1016/0022-0728(95)04229-x

Cited by 3 publications

(1 citation statement)

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“…Spectroelectrochemistry has been applied to investigate the electroreductive mechanism of viologen [2] and the dimerization of viologen radical cations with a dimerization rate constant of 10 4 M ¹1 s ¹1 [14,15]. Notably, the interaction between viologen and various electrode surfaces has received considerable interest [13,[16][17][18]. A previous investigation examined the adsorptive behaviors of viologen on gold (Au) electrode with electrochemical quartz crystal microbalance (EQCM) technique [16].…”

Section: Introductionmentioning

confidence: 99%

EQCM Studies of Paraquat on Gold Electrode Modified with Electropolymerized Film

1998

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This study presents a polyviologen (PV) modified gold/quartz electrode to detect paraquat (MV 2þ ) by electrochemical quartz crystal microbalance (EQCM) method. Some electroactive viologens (V 2þ ) reside in the electropolymerization achieved in pH 4.2 Britton-Robinson (BR) buffer solution containing soluble viologen oligomer. Closely examining the EQCM and cyclic voltammetry (CV) results reveal that V 2þ binds in the PV film and is electroreduced to form its relatively hydrophobic cation radical (V þ. ), which may cause the anions and hydrated water originally incorporated in the PV layer to be expelled. Moreover, while the negative potential is scanned over ¹0.55 V, the dissolved MV 2þ is reduced through V þ. to form its corresponding cation radical (MV þ.) and then becomes a dimer with the bound V þ. among the PV layer. According to our results, such dimerization possesses good reversibility so that the resonant frequency of the subsequent PV modified Au/quartz electrode can return to its initial value under the potential scanning within an appropriate region (i.e., from 0 to ¹0.7 V) and oxygen-free condition. Moreover, a linear calibration plot for detecting MV 2þ is also obtained in the range from 0 to 1.2 mM, having a detection limit of 0.1 mM.

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