Studies on the catalytic reduction of iodate at glassy carbon electrodes modified by molybdenum oxides

The electroreduction of iodate at glassy carbon discs modified by molybdenum oxide films in sulfuric acid medium is discussed. Studies carried out in the pH range 1.8-3.0 with Mo(VI) in solution show that at more acidic conditions the catalytic response is much larger since protons participate in the oxygen abstraction step when the substrate is reduced. Rotating disc experiments performed in solutions containing both Mo(VI) and iodate at pH 1.8 confirmed that an immobilised form of molybdenum is responsible for the reduction of the substrate, even though at more acidic solutions the film is partially solubilised. The results of voltammetric experiments carried out with a glassy carbon electrode coated by the molybdenum oxide layer established that iodide is generated in the electroreduction of iodate. (C) 1999 Elsevier Science S.A. All rights reserved.