Surface strontium enrichment on highly active perovskites for oxygen electrocatalysis in solid oxide fuel cells

Ethan J. Crumlin, Eva Mutoro, Zhi Liu, Michael E. Grass, Michael D. Biegalski, Yueh-Lin Lee, Dane Morgan, Hans M. Christen, Hendrik Bluhm, Yang Shao-Horn

Research output: Contribution to journalArticlepeer-review

236 Scopus citations

Abstract

Perovskite oxides have high catalytic activities for oxygen electrocatalysis competitive to platinum at elevated temperatures. However, little is known about the oxide surface chemistry that influences the activity near ambient oxygen partial pressures, which hampers the design of highly active catalysts for many clean-energy technologies such as solid oxide fuel cells. Using in situ synchrotron-based, ambient pressure X-ray photoelectron spectroscopy to study the surface chemistry changes, we show that the coverage of surface secondary phases on a (001)-oriented La 0.8Sr 0.2CoO 3-δ (LSC) film becomes smaller than that on an LSC powder pellet at elevated temperatures. In addition, strontium (Sr) in the perovskite structure enriches towards the film surface in contrast to the pellet having no detectable changes with increasing temperature. We propose that the ability to reduce surface secondary phases and develop Sr-enriched perovskite surfaces of the LSC film contributes to its enhanced activity for O 2 electrocatalysis relative to LSC powder-based electrodes. © 2012 The Royal Society of Chemistry.
Original languageEnglish (US)
Pages (from-to)6081
JournalEnergy & Environmental Science
Volume5
Issue number3
DOIs
StatePublished - 2012
Externally publishedYes

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