Search

Over 200 years of development of modern electrochemistry was divided into five periods. Period I from the beginning up to the end of nineteenth century, Period II from 1901 to 1945, Period III from 1946 to 1965, Period IV from 1966 to 1990, and the last Period V from 1991 till the present. This division is based on (1) use of different research methods in these periods, as well as (2) different intensity and organization of research work. In each period, the main research interests were briefly characterized, followed by short discussion of the main achievements. The expected trends of future development of electrochemistry were also briefly discussed.

Electrodeposition of well-adhering polypyrrole-based hybrid films containing hexacyanoferrate(II,III) anions from neutral solutions of pyrrole and potassium hexacyanoferrate(II) on medium carbon (0.48% C) steel has been described. The resulting polypyrrole coatings that are doped with hexacyanoferrate(II,III) anions show protective properties against pitting corrosion of carbon steel substrates in strongly acidic media containing chlorides (0.1 mol dm−3 HCl + 0.4 mol dm−3 NaCl). Polypyrrole acts as a stable host matrix for inorganic anions. The presence of negatively charged species (hexacyanoferrates) in the polymer backbone tends to block the access of pitting-causing anions (chlorides) to the surface of steel. The Fe(CN)63-/4− anions existing in the vicinity of steel substrate stabilizes its surface by forming an overcoating in the form of sparingly soluble metal hexacyanoferrate, mostly Prussian blue (PB), microstructures. It has been demonstrated that by applying cyclic voltammetry and X-ray photoelectron spectroscopy, the presence of traces of free cyanide anions promotes the formation of PB on carbon steel surface which results in increasing the adherence of polypyrrole-based films to the metallic substrate. Morphology of the protective composite films is also addressed.

MERCURY electrodes used in electrochemistry are often prepared by plating mercury on solid electrodes. The formation of amalgams in these conditions has been in general disregarded. We have already shown1 that when gold or gold-plated electrodes are covered with mercury, there are electrode reactions different from those on pure mercury, owing to formation of intermetallic compounds.

IN the application of the hanging mercury drop electrode to analytical determination of trace metals we have used very dilute solutions1 in which no mutual interaction of metals was observed, even in the presence of more than one metallic species. We wish to report an investigation of the conditions in which such interaction effect cannot be neglected.

IT is usual to study electrode processes using hanging-mercury microelectrodes. Some authors prepare these electrodes by hanging a small mercury drop on a gold wire or a gold-plated platinum wire1,2, deliberately neglecting the presence of the gold for its electropositive potential. Such an electrode is however an amalgam electrode, and, as we have shown3, gold can influence the electrode processes of those metals which combine with it to form intermediate compounds.