Voltammetric study of the immobilization of palladium at the surface of carbon paste electrodes

Abstract

AbstractThe immobilization of palladium at the surface of unmodified carbon paste electrodes is studied by cyclic voltammetry. Some features of the voltammetric behavior of palladium(II) at carbon paste electrode in chloride solution are elucidated. Through pretreatment at 0 V (vs. Ag/AgCl) palladium is bound at the surface of the carbon paste. The amount immobilized depends on the composition of the solution, polarization time, electrode potential and stirring. During an anodic scan the surface‐bound palladium is oxidized at about +0.6 V; the well‐shaped peaks can be utilized for the determination of the immobilized Pd. The detection limit is about 5 × 10−6 M Pd2+ after 5 min polarization at 0 V (vs. Ag/AgCl) with stirring (base electrolyte 1 M KCl, pH 5.5). The rather complicated influence of hydrogen ions on the reactions at the palladium/carbon surface is discussed. Palladium and hydrogen can be “deposited” simultaneously at the carbon paste surface through cathodic polarization. Electrode reactions related to the observed peaks are suggested.