title: Nanoscale structural oscillations in perovskite oxides induced by oxygen evolution.
abstract: Understanding the interaction between water and oxides is critical for many technological applications, including energy storage, surface wetting/self-cleaning, photocatalysis and sensors. Here, we report observations of strong structural oscillations of Ba0.5Sr0.5Co0.8Fe0.2O3-δ(BSCF) in the presence of both H2O vapour and electron irradiation using environmental transmission electron microscopy. These oscillations are related to the formation and collapse of gaseous bubbles. Electron energy-loss spectroscopy provides direct evidence of O2formation in these bubbles due to the incorporation of H2O into BSCF. SrCoO3-δwas found to exhibit small oscillations, while none were observed for La0.5Sr0.5CoO3-δand LaCoO3. The structural oscillations of BSCF can be attributed to the fact that its oxygen 2p-band centre is close to the Fermi level, which leads to a low energy penalty for oxygen vacancy formation, high ion mobility, and high water uptake. This work provides surprising insights into the interaction between water and oxides under electron-beam irradiation.
authors.affiliation: Department of Materials Science and Engineering, Cambridge, Massachusetts 02139, USA.
authors.forename: Binghong
authors.identifier: 0000-0002-2919-3235
authors.initials: B
authors.lastname: Han
authors.affiliation: Department of Materials Science and Engineering, Cambridge, Massachusetts 02139, USA.
authors.forename: Kelsey A
authors.initials: KA
authors.lastname: Stoerzinger
authors.affiliation: Institute of Materials, École Polytechnique Fédérale de Lausanne, Station 12, CH-1015 Lausanne, Switzerland.
authors.forename: Vasiliki
authors.initials: V
authors.lastname: Tileli
authors.affiliation: Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973-5000, USA.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Gamalski
authors.affiliation: Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973-5000, USA.
authors.forename: Eric A
authors.identifier: 0000-0002-3366-2153
authors.initials: EA
authors.lastname: Stach
authors.affiliation: Department of Materials Science and Engineering, Cambridge, Massachusetts 02139, USA.|Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Yang
authors.initials: Y
authors.lastname: Shao-Horn