Oxygen reduction reactions in the SOFC cathode of Ag/CeO2

Jeng Han Wang, Mei Lin Liu*, M. C. Lin

*此作品的通信作者

研究成果: 雜誌貢獻期刊論文同行評審

98 引文 斯高帕斯(Scopus)

摘要

The interactions between oxygen molecules and a silver surface or a CeO2(111) supported atomic layer of silver are predicted using first-principles calculations based on spin polarized DFT with PAW method. The juncture between the CeO2(111), the atomic layer of silver, and O2 represents a triple-phase boundary (TPB) whereas the interface between silver surfaces and O2 corresponds to a 2-phase boundary (2PB) in a solid oxide fuel cell (SOFC). Results suggest that the O2 dissociation process on a monolayer of silver supported by CeO2(111) surfaces (or TPB) with oxygen vacancies has lower reaction barrier than on silver surfaces (or 2PB), and the dissociated oxygen ions can quickly bond with subsurface Ce atom via a barrierless and highly exothermic reaction. The oxygen vacancies at TPB are found to be responsible for the lower energy barrier and high exothermicity because of the strong interaction between subsurface Ce and adspecies, implying that oxygen molecules prefer being reduced at TPB than on silver surfaces (2PB). The results suggest that, for a silver-based cathode in a SOFC, the adsorption and dissociation of oxygen occur rapidly and the most stable surface oxygen species would be the dissociated oxygen ion with - 0.78|e| Bader charges; the rate of oxygen reduction is most likely limited by subsequent processes such as diffusion or incorporation of the oxygen ions into the electrolyte.

原文英語
頁(從 - 到)939-947
頁數9
期刊Solid State Ionics
177
發行號9-10
DOIs
出版狀態已發佈 - 2006 3月 31
對外發佈

ASJC Scopus subject areas

  • 化學 (全部)
  • 材料科學(全部)
  • 凝聚態物理學

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