Electrochemical oxidation of arsenic (III) at a glassy carbon electrode modified in a solution containing palladium chloride and sodium hexachloroiridate (IV)

Abstract

Arsenic (III) has been oxidized at a glassy carbon electrode modified with a film of mixed metal oxides iridium and palladium. Cyclic voltammetry of the As(III)/As(V) redox process reveals that the peak potential of the anodic process is 0.72V (vs SCE) at a scan rate of 50mV/s. This is the lowest over potential reported so far for this oxidation. The process has been interpreted as occurring by the mediation of electron transfer through the oxidation-reduction of the film constituents. The heterogeneous rate constant of the process, determined by rotating disk electrode voltammetry, is 6.8 x 10^-3 cm/s at 0.72V.