Kinetics of oxidation of H2 and reduction of H2O in Ni-YSZ based solid oxide cells

Sune Dalgaard Ebbesen, Mogens Bjerg Mogensen

Research output: Contribution to journalConference articleResearchpeer-review

Abstract

Reduction of H2O and oxidation of H2 was studied in a Ni-YSZ electrode supported Solid Oxide Cells produced at DTU Energy conversion (former Risø DTU). Polarisation (i-V) and electrochemical impedance spectroscopic characterisation show that the kinetics for reduction of H 2O is slower compared to oxidation of H2. The kinetic differences cannot be explained by the reaction mechanisms which are similar in the two cases but are rather an effect of the thermodynamics. The preliminary analysis performed in this study show that the slow kinetic for reduction is partly related to the endothermic nature of the reaction, cooling the active electrode, thereby leading to slower kinetics at low current densities. Likewise, the increased kinetic for oxidation was found to be related to the exothermic nature of the reaction, heating the active electrode, and thereby leading to faster kinetics. At higher current densities an increase caused by diffusion becomes more pronounced. © The Electrochemical Society.
Original languageEnglish
JournalE C S Transactions
Volume50
Issue number49
Pages (from-to)167-182
ISSN1938-5862
DOIs
Publication statusPublished - 2012
EventPacific Rim Meeting on Electrochemical and Solid-State Science: 222nd Meeting of ECS — The Electrochemical Society and 2012 Fall Meeting of The Electrochemical Society of Japan - Hawaii Convention Center and the Hilton Hawaiian Village, Honolulu, United States
Duration: 7 Oct 201212 Oct 2012
http://www.electrochem.org/meetings/biannual/222/222.htm

Conference

ConferencePacific Rim Meeting on Electrochemical and Solid-State Science
LocationHawaii Convention Center and the Hilton Hawaiian Village
CountryUnited States
CityHonolulu
Period07/10/201212/10/2012
Internet address

Keywords

  • Energy conversion
  • Nickel
  • Oxidation
  • Reaction kinetics
  • Thermodynamics
  • Kinetics

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