Long-term stability of oxygen surface exchange kinetics of Pr0.8Ca0.2FeO3-δ against SO2-poisoning

Christian Berger, Edith Bucher*, Christian Gspan, Alexander Menzel, Werner Sitte

*Korrespondierende/r Autor/in für diese Arbeit

Publikation: Beitrag in einer FachzeitschriftArtikel

Abstract

The long-term stability of the oxygen exchange kinetics of the Sr- and Co-free solid oxide fuel cell (SOFC) and solid oxide electrolyser cell (SOEC) air electrode material Pr0.8Ca0.2FeO3-δ (PCF82) is investigated by in-situ dc-conductivity relaxation measurements. The chemical oxygen surface exchange coefficient kchem is determined as a function of time at 700 °C under ideal (O2-Ar atmosphere) and accelerated ageing conditions (O2-Ar with 2 ppm SO2). In pure O2-Ar PCF82 shows fast oxygen surface exchange kinetics with kchem = 6 × 10−4 cm s−1 and excellent stability for 1000 h. Due to the addition of 2 ppm SO2 to the test gas only a moderate degradation occurs with kchem decreasing to 8 × 10−5 cm s−1 during further 1000 h. Post-test analyses by scanning (transmission) electron microscopy and X-ray photoelectron spectroscopy show S-rich secondary phases in the near-surface region of the SO2-poisoned sample. These inactive phases occur in an island-like arrangement of relatively large crystals, whereas significant amounts of the surface remain unaffected. This effect explains the high stability of the oxygen exchange kinetics of PCF82 against SO2-poisoning in comparison to state-of-the art materials like La0.6Sr0.4CoO3-δ (LSC64).

Originalspracheenglisch
Seiten (von - bis)82-89
Seitenumfang8
FachzeitschriftSolid State Ionics
Jahrgang326
DOIs
PublikationsstatusVeröffentlicht - 15 Nov 2018

ASJC Scopus subject areas

  • !!Chemistry(all)
  • !!Materials Science(all)
  • !!Condensed Matter Physics

Fingerprint

Untersuchen Sie die Forschungsthemen von „Long-term stability of oxygen surface exchange kinetics of Pr<sub>0.8</sub>Ca<sub>0.2</sub>FeO<sub>3-δ</sub> against SO<sub>2</sub>-poisoning“. Zusammen bilden sie einen einzigartigen Fingerprint.

Dieses zitieren