Electrochemical determination of oxygen stoichiometry and entropy in oxides

Birgit Zachau-Christiansen, Torben Jacobsen, Steen Skaarup

Research output: Contribution to journalConference articleResearchpeer-review


The oxygen stoichiometry of CeO2 and Ce0.82Gd0.18O1.91 is determined by a combination of cyclic voltammetry and coulometric titration. The electrochemical cell employed is an oxygen pumping cell, in which the oxide is subjected to different oxygen pressures corresponding to the potential imposed in the temperature range 800-1000 degrees C. With scan rates of 2 mu V/s potential sweeps on CeO2 are reversible. The change in entropy is determined by either subtraction of e.m.f. curves obtained by potential sweeps of different temperatures or by measuring the e.m.f. during a temperature scan. The latter method yields the most reliable results. Potential sweeps on Ce0.8Ca0.2O1.8 suggest that calcium is expelled from the lattice.
Original languageEnglish
JournalSolid State Ionics
Pages (from-to)725-731
Publication statusPublished - Jul 1996
Event10th International Conference on Solid State Ionics (SSI-10) - Singapore, Singapore
Duration: 3 Dec 19958 Dec 1995
Conference number: 10


Conference10th International Conference on Solid State Ionics (SSI-10)
SponsorNational University of Singapore


  • oxygen stoichiometry
  • cyclic voltammetry

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