Department of Materials Science and Engineering, Cambridge, Massachusetts 02139, USA.
Institute of Materials, École Polytechnique Fédérale de Lausanne, Station 12, CH-1015 Lausanne, Switzerland.
Nat Mater. 2017 Jan;16(1):121-126. doi: 10.1038/nmat4764. Epub 2016 Oct 3.
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 BaSrCoFeO (BSCF) in the presence of both HO 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 formation in these bubbles due to the incorporation of HO into BSCF. SrCoO was found to exhibit small oscillations, while none were observed for LaSrCoO and LaCoO. 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.
理解水和氧化物之间的相互作用对于许多技术应用至关重要，包括能量存储、表面润湿/自清洁、光催化和传感器。在这里，我们使用环境透射电子显微镜报告了在 HO 蒸气和电子辐照存在下 BaSrCoFeO（BSCF）的强烈结构振荡的观察结果。这些振荡与气态气泡的形成和坍塌有关。电子能量损失光谱提供了由于 HO 掺入 BSCF 而导致这些气泡中 O 形成的直接证据。发现 SrCoO 表现出小的振荡，而 LaSrCoO 和 LaCoO 则没有观察到。BSCF 的结构振荡可归因于其氧 2p 带中心接近费米能级，这导致氧空位形成的能量代价低、离子迁移率高和高吸水性。这项工作为电子束辐照下水和氧化物之间的相互作用提供了令人惊讶的见解。
