Electrodeposition of pyrogallol versus pyrocatechol using cyclic voltammetry and chronoamperometry

Abstract

• The electrodeposition of pyrocatechol is compared with that of pyrogallol. • In case of CV deposition pyrogallol yields impermeable films of higher impedance. • In case of chronoamperometry, pyrocatechol yields impermeable films of higher impedance. The electrodeposition of films from redox active molecules has become an attractive surface functionalization method owing to its surface selectivity and one pot nature. Many investigations focused on the deposition mechanism of particular molecules such as aniline or thiophene. Fewer studies focused on derivatives of phenols and very few were aimed to compare the electrochemical properties of the obtained films when the chemical nature of the phenol derivative is changed, for instance upon the addition of an hydroxyl group on the benzene cycle, or when the nature of the deposition method is changed, namely variable (cyclic voltammetry, CV) or constant potential (chronoameprometry, CA). This investigation compares the influence of the film deposition method on the electrochemical properties of deposits made from pyrogallol or pyrocatechol on amorphous carbon electrodes. It is shown that CA is more efficient for the deposition of pyrocatechol based films than for pyrogallol based films. On the other hand, a lower number of CV cycles is required to obtained films impermeable to hexacyanoferrate anions in the case of pyrogallol compared to pyrocatechol.