Journal of the Electrochemical Society, Vol.145, No.1, 53-58, 1998
Electrochemical study of NO conversion from Fe(II)-EDTA-NO complex on Pt electrodes
The Fe(LI)-ethylenediaminetetraacetic acid (EDTA)-NO complex formed by interaction of gaseous nitrous oxide (ca. 200 ppm) and Fe(II)-EDTA in aqueous solution was found to be converted electrochemically on platinum electrodes at potentials below ca. -0.6 V-SCE indicating the cathodic reduction of NO. In addition to our previous studies by which the indirect conversion of NO with dithionite as a redox mediator was confirmed, the present results should elucidate the possibility of the direct electrochemical conversion of NO in mediator-free solutions. To clearly separate this process from other reactions in the system, the electrochemical behavior of Fe(II)-EDTA and Fe(III)-EDTA was studied over a wide potential range at different pH values. Five electrode reactions could be identified, which include the oxidation/reduction of Fe2+/Fe3+ in the EDTA complex, the reduction of EDTA, the-reduction of protons, the cathodic deposition of iron, and the anodic decomposition of EDTA. The electrochemical deposition of iron from Fe(II)-EDTA at potentials E < -1.0 V-SCE was confirmed by electrochemical quartz crystal microbalance measurements and energy-dispersive x-ray analysis.
Keywords:ETHYLENEDIAMINETETRAACETIC ACID;INFRARED-SPECTROSCOPY;PLATINUM-ELECTRODES;NITROUS-OXIDE;EDTA;OXIDATION;REDUCTION;REMOVAL;METAL