Comparison of the cyclic voltammetry of benzene-1,2-diol and benzene-1,2,3-triol and their ability to form films on the carbon working electrode after a single potential sweep cycle

Abstract

The deposition of thin films on electrode surfaces by methods like cyclic voltammetry (CV) or chronoamperometry was for a long time considered as a drawback owing to the passivation of the electrode and a subsequent reduction in its ability to allow for the determination of electroactive compounds. However, the easy deposition of thin fims from electroactive molecules is also a surface functionalization method. In this article the ability of 1,2-dihydroxybenzene (catechol) and of 1,2,3-trihydroxybenzene (pyrogallol) to form films impermeable to potassium hexacyanoferrate after only one CV « deposition » cycle will be compared. The addition of an additional hydroxyl group on catechol improves the film forming ability in the potential sweep rate window between 1 and 100 mV.s^-1. The obtained data will be interpreted in terms of the reversible (mostly for catechol) versus irreversible nature (in the case of pyrogallol) of the « deposition » cycle.