Potential scan rate dependence of underpotential and bulk depositions of lead on screen-printed silver electrodes

Abstract

This is the first report on studies of the underpotential deposition of Pb (upd-Pb) on a disposable screen-printed silver electrode (AgSPE, non-single crystalline surface). The dependence of upd-Pb and bulk Pb deposition (bulk-Pb) on potential scan rate ( ν) was demonstrated for the AgSPE in pH 3 KNO 3/HNO 3 solutions. At ν=20 mV s −1, the extent of formation of reversible upd-Pb was ∼15 times less than that of irreversible bulk-Pb. However, for ν>100 mV s −1, only the upd-Pb was observed. Scanning electron microscopic (SEM) analysis speculated 3D-nucleation ( hcp) of bulk-Pb on the AgSPE at low scan rate ( ν=1 mV s −1). On the other hand, at a faster scan rate ( ν=300 mV s −1), no marked crystallites were obtained. By interpretation with the CV results, the later case was proved to be formation and complete stripping of the upd-Pb on the AgSPE and this property was further utilized for analytical application. The nearly reversible behavior of the upd-Pb process at the disposable AgSPE is a judicious choice for the effective stripping analysis of Pb by square-wave voltammetry.