Corrosion of ruthenium dioxide based cathodes in alkaline medium caused by reverse currents
2014 (English)In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 0019-4686, Vol. 146, 30-36 p.Article in journal (Refereed) Published
A reverse current obtained during power shutdowns in industrial processes, such as chlor-alkali production or alkaline water electrolysis, is deleterious for hydrogen evolving ruthenium dioxide (Ru02) based cathodes. It has been observed that RuO2 coatings after a power shutdown, necessary for e.g. maintenance, are severely damaged unless polarization rectifiers are employed. In this work we show why these types of cathodes are sensitive to reverse currents, i.e. anodic currents, after hydrogen evolution. RuO2 coatings deposited on nickel substrates were subjected to different electrochemical treatments such as hydrogen evolution, oxygen evolution, or reverse currents in 8 M NaOH at 90 degrees C. Polarity inversion was introduced after hydrogen evolution to simulate the effect of reverse currents. Because of chemical interaction with hydrogen, a significant amount of the RuO2 coating was transformed into hydroxylated species during cathodic polarization. Our study shows that these hydroxylated phases are highly sensitive to electrochemical corrosion during anodic polarization after extended hydrogen evolution.
Place, publisher, year, edition, pages
Elsevier , 2014. Vol. 146, 30-36 p.
Hydrogen evolution; RuO2 coatings; Phase transformation; Polarity inversion; Corrosion
IdentifiersURN: urn:nbn:se:liu:diva-113016DOI: 10.1016/j.electacta.2014.09.024ISI: 000345226100005OAI: oai:DiVA.org:liu-113016DiVA: diva2:778964
Funding Agencies|Swedish Research Council [2007-5059]; European Research Council under the European Communities/ERC ; Swedish Research Council (VR) [642-2013-8020]; KAW Fellowship program2015-01-122015-01-082015-08-06