Studying the binding of Cd2+ by ω-mercaptoalkanoic acid self assembled monolayers by cyclic voltammetry and scanning electrochemical microscopy (SECM).

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Cyclic voltammetry (CV) and scanning electrochem. microscopy (SECM) were used for studying the binding of protons and Cd(II) ions by 8-mercaptooctanoic acid monolayer that was assembled on an Au surface. Binding of the cations by the monolayer affected the kinetics of electron transfer to neg. charged species, i.e., IrCl63-, in the soln. Increasing the pH of the soln. causes the CV of IrCl63- to become less reversible and the feedback current of the SECM to decrease as the distance between the microelectrode and the surface decreases. However, addn. of Cd2+ to the soln. at pH 6.8 increases the CV reversibility and the feedback current of the SECM of neutralizing the neg. charge of the monolayer by the metallic ions. A model based on the Frumkin correction was used to account for these findings and for extg. the heterogeneous assocn. const. of Cd2+ by the monolayer. [on SciFinder(R)]


CAPLUS AN 2005:610582(Journal)