Electrochemical behaviour of Vanadium(V) on electrochemically synthesized magnetite film electrodes

• Published in: Journal of electroanalytical chemistry (Lausanne, Switzerland) Vol. 819; pp. 283 - 288
• Main Authors: Dabrowski, Sergio G., Tudino, Mabel B., Molina, Fernando V.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.06.2018; Elsevier Science Ltd
• Subjects: Carbon; Conducting polymer; Cyclic voltammetry; Electroactivity; Electrochemical analysis; Electrodes; Glassy carbon; Groundwater; Iron oxide; Magnetic fields; Magnetite; Oxidation; Reduction; Reproducibility; Vanadium; Voltammetry; Water infiltration; Cyclic voltammetry; Conducting polymer; Iron oxide
• ISSN: 1572-6657; 1873-2569
• DOI: 10.1016/j.jelechem.2017.10.053

In this work, the electrochemical response of Vanadium(V) species on magnetite film electrodes is investigated. Magnetite is deposited electrochemically on glassy carbon electrodes, with an intermediate layer of poly(thiophene) to avoid water infiltration. These electrodes show good reproducibility and stability up to pH=2.0. Mononuclear V(V) species show low electroactivity on this surface. Cyclic voltammetry at low V(V) concentration shows that it is electroactive only at pH<3. i.e. as VO2+. A single reduction peak is observed at ~−0.7V vs SCE (at 50mVs−1), and an oxidation one at ~0.5V vs SCE, indicating high irreversibility of the V(V)/V(IV) couple; these peaks are found to be solution phase reactions. These features are interpreted in terms of mononuclear V species. At higher V concentrations, where polymeric V(V) species are dominant, a somewhat higher electroactivity is observed, with two reduction peaks and two/three oxidation peaks. •A magnetite film electrode is developed and employed to study the V/Fe3O4 system.•At concentrations below 1mM V(V) shows low electroactivity on magnetite.•Polynuclear V(V) species show somewhat higher electroactivity.