Ruthenium based DSA((R)) in chlorate electrolysis - critical anode potential and reaction kinetics
2003 (English)In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 0019-4686, Vol. 48, no 5, 473-481 p.Conference paper (Refereed)
Ruthenium based DSA((R))s have been investigated in chlorate electrolyte using rotating discs made from commercial electrodes. Measurements of the voltammetric charge, q*, and of iR-corrected polarisation curves up to current densities of 40 kA/m(2) Were recorded on new anodes and on aged anodes from 3 years of production in a chlorate plant. Anodic polarisation curves in chloride containing electrolytes bend towards a higher slope at approximately 1.2 V versus Ag/AgCl, likely due to oxidation of ruthenium. The potential and current density at which the curves bend have been defined as the critical potential, E-cr, and the critical current density, i(cr). New anodes that operate at a relatively high potential, > E-cr, obtain an increase in real surface area and thereby a decrease in anode potential and in the selectivity for oxygen formation during the first months of operation. Experiments at constant ionic strength under chlorate process conditions showed that E-cr decreased with increasing chloride concentration with a factor of -0.09 V/log Cl-, whereas i(cr) increased with increasing chloride concentration. The chlorine evolution reaction was of the first order with respect to chloride concentration. A possible reaction mechanism for chlorine formation is suggested.
Place, publisher, year, edition, pages
2003. Vol. 48, no 5, 473-481 p.
chlorate electrolysis, DSA, RuO2, critical potential, reaction kinetics, oxygen evolution, chlorine evolution, oxide electrodes, acid-media, ruo2, mechanism, ti/ruo2, electrocatalysis, surface, iro2
IdentifiersURN: urn:nbn:se:kth:diva-22213ISI: 000180654800003OAI: oai:DiVA.org:kth-22213DiVA: diva2:340911
QC 201005252010-08-102010-08-10Bibliographically approved