Nanoscale structural oscillations in perovskite oxides induced by oxygen evolution

• Published in: Nature materials Vol. 16; no. 1; pp. 121 - 126
• Main Authors: Han, Binghong, Stoerzinger, Kelsey A., Tileli, Vasiliki, Gamalski, Andrew D., Stach, Eric A., Shao-Horn, Yang
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.01.2017; Nature Publishing Group
• Subjects: 121/143; 639/301/299/161/886; 639/301/930/328/2082; 639/638/542; Biomaterials; Bubbles; Center for Functional Nanomaterials; Collapse; Condensed Matter Physics; electron beam interactions; Electron irradiation; ENERGY STORAGE; Formations; Irradiation; MATERIALS SCIENCE; Nanostructure; Nanotechnology; Optical and Electronic Materials; Oscillations; Oxidation; Oxides; Oxygen; Perovskite; photocatalysis; Sensors; Spectroscopy; Water; water splitting; Water uptake
• ISSN: 1476-1122; 1476-4660; 1476-4660
• DOI: 10.1038/nmat4764

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 Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3−δ (BSCF) in the presence of both H 2 O 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 O 2 formation in these bubbles due to the incorporation of H 2 O into BSCF. SrCoO 3−δ was found to exhibit small oscillations, while none were observed for La 0.5 Sr 0.5 CoO 3−δ and LaCoO 3 . The structural oscillations of BSCF can be attributed to the fact that its oxygen 2 p -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. Understanding interactions between water and oxides is crucial for energy storage and photocatalysis. The combined effect of water and electron irradiation on perovskite catalysts results in structural oscillation triggered by gaseous bubbles.